Merge branch 'db/checkout'
authorJunio C Hamano <gitster@pobox.com>
Wed, 27 Feb 2008 20:53:26 +0000 (12:53 -0800)
committerJunio C Hamano <gitster@pobox.com>
Wed, 27 Feb 2008 20:53:26 +0000 (12:53 -0800)
* db/checkout: (21 commits)
checkout: error out when index is unmerged even with -m
checkout: show progress when checkout takes long time while switching branches
Add merge-subtree back
checkout: updates to tracking report
builtin-checkout.c: Remove unused prefix arguments in switch_branches path
checkout: work from a subdirectory
checkout: tone down the "forked status" diagnostic messages
Clean up reporting differences on branch switch
builtin-checkout.c: fix possible usage segfault
checkout: notice when the switched branch is behind or forked
Build in checkout
Move code to clean up after a branch change to branch.c
Library function to check for unmerged index entries
Use diff -u instead of diff in t7201
Move create_branch into a library file
Build-in merge-recursive
Add "skip_unmerged" option to unpack_trees.
Discard "deleted" cache entries after using them to update the working tree
Send unpack-trees debugging output to stderr
Add flag to make unpack_trees() not print errors.
...

Conflicts:

Makefile

12 files changed:
1  2 
Makefile
builtin-branch.c
builtin-commit.c
builtin-merge-recursive.c
builtin-read-tree.c
builtin.h
cache.h
contrib/examples/git-checkout.sh
git.c
read-cache.c
t/t7201-co.sh
unpack-trees.c
diff --combined Makefile
index 8d9f11e75e8fb1095761fd7fd25e66b1d73e6fa2,40fa41b5f3a914cfb82366158e8e27bac3bb8938..a5b6eebf1a0b65b481f6dd8f1e38006b46e87c83
+++ b/Makefile
@@@ -3,9 -3,6 +3,9 @@@ all:
  
  # Define V=1 to have a more verbose compile.
  #
 +# Define FREAD_READS_DIRECTORIES if your are on a system which succeeds
 +# when attempting to read from an fopen'ed directory.
 +#
  # Define NO_OPENSSL environment variable if you do not have OpenSSL.
  # This also implies MOZILLA_SHA1.
  #
@@@ -45,8 -42,6 +45,8 @@@
  #
  # Define NO_MKDTEMP if you don't have mkdtemp in the C library.
  #
 +# Define NO_SYS_SELECT_H if you don't have sys/select.h.
 +#
  # Define NO_SYMLINK_HEAD if you never want .git/HEAD to be a symbolic link.
  # Enable it on Windows.  By default, symrefs are still used.
  #
  # Define THREADED_DELTA_SEARCH if you have pthreads and wish to exploit
  # parallel delta searching when packing objects.
  #
 +# Define INTERNAL_QSORT to use Git's implementation of qsort(), which
 +# is a simplified version of the merge sort used in glibc. This is
 +# recommended if Git triggers O(n^2) behavior in your platform's qsort().
 +#
  
  GIT-VERSION-FILE: .FORCE-GIT-VERSION-FILE
        @$(SHELL_PATH) ./GIT-VERSION-GEN
@@@ -226,7 -217,7 +226,7 @@@ BASIC_CFLAGS 
  BASIC_LDFLAGS =
  
  SCRIPT_SH = \
-       git-bisect.sh git-checkout.sh \
+       git-bisect.sh \
        git-clone.sh \
        git-merge-one-file.sh git-mergetool.sh git-parse-remote.sh \
        git-pull.sh git-rebase.sh git-rebase--interactive.sh \
        git-lost-found.sh git-quiltimport.sh git-submodule.sh \
        git-filter-branch.sh \
        git-stash.sh \
 -      git-help--browse.sh
 +      git-web--browse.sh
  
  SCRIPT_PERL = \
        git-add--interactive.perl \
@@@ -265,23 -256,23 +265,23 @@@ PROGRAMS = 
        git-upload-pack$X \
        git-pack-redundant$X git-var$X \
        git-merge-tree$X git-imap-send$X \
-       git-merge-recursive$X \
        $(EXTRA_PROGRAMS)
  
  # Empty...
  EXTRA_PROGRAMS =
  
+ # List built-in command $C whose implementation cmd_$C() is not in
+ # builtin-$C.o but is linked in as part of some other command.
  BUILT_INS = \
        git-format-patch$X git-show$X git-whatchanged$X git-cherry$X \
        git-get-tar-commit-id$X git-init$X git-repo-config$X \
        git-fsck-objects$X git-cherry-pick$X git-peek-remote$X git-status$X \
+       git-merge-subtree$X \
        $(patsubst builtin-%.o,git-%$X,$(BUILTIN_OBJS))
  
  # what 'all' will build and 'install' will install, in gitexecdir
  ALL_PROGRAMS = $(PROGRAMS) $(SCRIPTS)
  
- ALL_PROGRAMS += git-merge-subtree$X
  # what 'all' will build but not install in gitexecdir
  OTHER_PROGRAMS = git$X gitweb/gitweb.cgi
  
@@@ -327,8 -318,7 +327,8 @@@ LIB_OBJS = 
        alloc.o merge-file.o path-list.o help.o unpack-trees.o $(DIFF_OBJS) \
        color.o wt-status.o archive-zip.o archive-tar.o shallow.o utf8.o \
        convert.o attr.o decorate.o progress.o mailmap.o symlinks.o remote.o \
-       transport.o bundle.o walker.o parse-options.o ws.o archive.o \
 -      transport.o bundle.o walker.o parse-options.o ws.o archive.o branch.o
++      transport.o bundle.o walker.o parse-options.o ws.o archive.o branch.o \
 +      alias.o
  
  BUILTIN_OBJS = \
        builtin-add.o \
        builtin-bundle.o \
        builtin-cat-file.o \
        builtin-check-attr.o \
+       builtin-checkout.o \
        builtin-checkout-index.o \
        builtin-check-ref-format.o \
        builtin-clean.o \
        builtin-merge-base.o \
        builtin-merge-file.o \
        builtin-merge-ours.o \
+       builtin-merge-recursive.o \
        builtin-mv.o \
        builtin-name-rev.o \
        builtin-pack-objects.o \
@@@ -513,17 -505,6 +515,17 @@@ ifeq ($(uname_S),IRIX64
        # for now, build 32-bit version
        BASIC_LDFLAGS += -L/usr/lib32
  endif
 +ifeq ($(uname_S),HP-UX)
 +      NO_IPV6=YesPlease
 +      NO_SETENV=YesPlease
 +      NO_STRCASESTR=YesPlease
 +      NO_MEMMEM = YesPlease
 +      NO_STRLCPY = YesPlease
 +      NO_MKDTEMP = YesPlease
 +      NO_UNSETENV = YesPlease
 +      NO_HSTRERROR = YesPlease
 +      NO_SYS_SELECT_H = YesPlease
 +endif
  ifneq (,$(findstring arm,$(uname_M)))
        ARM_SHA1 = YesPlease
  endif
@@@ -626,10 -607,6 +628,10 @@@ endi
  ifdef NO_C99_FORMAT
        BASIC_CFLAGS += -DNO_C99_FORMAT
  endif
 +ifdef FREAD_READS_DIRECTORIES
 +      COMPAT_CFLAGS += -DFREAD_READS_DIRECTORIES
 +      COMPAT_OBJS += compat/fopen.o
 +endif
  ifdef NO_SYMLINK_HEAD
        BASIC_CFLAGS += -DNO_SYMLINK_HEAD
  endif
@@@ -660,9 -637,6 +662,9 @@@ ifdef NO_UNSETEN
        COMPAT_CFLAGS += -DNO_UNSETENV
        COMPAT_OBJS += compat/unsetenv.o
  endif
 +ifdef NO_SYS_SELECT_H
 +      BASIC_CFLAGS += -DNO_SYS_SELECT_H
 +endif
  ifdef NO_MMAP
        COMPAT_CFLAGS += -DNO_MMAP
        COMPAT_OBJS += compat/mmap.o
@@@ -734,15 -708,10 +736,15 @@@ ifdef NO_MEMME
        COMPAT_CFLAGS += -DNO_MEMMEM
        COMPAT_OBJS += compat/memmem.o
  endif
 +ifdef INTERNAL_QSORT
 +      COMPAT_CFLAGS += -DINTERNAL_QSORT
 +      COMPAT_OBJS += compat/qsort.o
 +endif
  
  ifdef THREADED_DELTA_SEARCH
        BASIC_CFLAGS += -DTHREADED_DELTA_SEARCH
        EXTLIBS += -lpthread
 +      LIB_OBJS += thread-utils.o
  endif
  
  ifeq ($(TCLTK_PATH),)
@@@ -836,13 -805,9 +838,10 @@@ git$X: git.o $(BUILTIN_OBJS) $(GITLIBS
  
  help.o: help.c common-cmds.h GIT-CFLAGS
        $(QUIET_CC)$(CC) -o $*.o -c $(ALL_CFLAGS) \
 +              '-DGIT_HTML_PATH="$(htmldir_SQ)"' \
                '-DGIT_MAN_PATH="$(mandir_SQ)"' \
                '-DGIT_INFO_PATH="$(infodir_SQ)"' $<
  
- git-merge-subtree$X: git-merge-recursive$X
-       $(QUIET_BUILT_IN)$(RM) $@ && ln git-merge-recursive$X $@
  $(BUILT_INS): git$X
        $(QUIET_BUILT_IN)$(RM) $@ && ln git$X $@
  
@@@ -857,6 -822,7 +856,6 @@@ $(patsubst %.sh,%,$(SCRIPT_SH)) : % : %
            -e 's|@@PERL@@|$(PERL_PATH_SQ)|g' \
            -e 's/@@GIT_VERSION@@/$(GIT_VERSION)/g' \
            -e 's/@@NO_CURL@@/$(NO_CURL)/g' \
 -          -e 's|@@HTMLDIR@@|$(htmldir_SQ)|g' \
            $@.sh >$@+ && \
        chmod +x $@+ && \
        mv $@+ $@
@@@ -961,7 -927,7 +960,7 @@@ git-%$X: %.o $(GITLIBS
  
  git-imap-send$X: imap-send.o $(LIB_FILE)
  
 -http.o http-walker.o http-push.o: http.h
 +http.o http-walker.o http-push.o transport.o: http.h
  
  git-http-push$X: revision.o http.o http-push.o $(GITLIBS)
        $(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) \
@@@ -1104,7 -1070,7 +1103,7 @@@ git.spec: git.spec.i
        mv $@+ $@
  
  GIT_TARNAME=git-$(GIT_VERSION)
 -dist: git.spec git-archive configure
 +dist: git.spec git-archive$(X) configure
        ./git-archive --format=tar \
                --prefix=$(GIT_TARNAME)/ HEAD^{tree} > $(GIT_TARNAME).tar
        @mkdir -p $(GIT_TARNAME)
diff --combined builtin-branch.c
index 9edf2eb8162eb7214e1b4d76dca8949c63e72847,1e0c9dea3f8a22f7714d51ad4ad00c30d436eac3..7e991030ca4def9e2be2f595809529e13a898c24
@@@ -12,6 -12,7 +12,7 @@@
  #include "builtin.h"
  #include "remote.h"
  #include "parse-options.h"
+ #include "branch.h"
  
  static const char * const builtin_branch_usage[] = {
        "git-branch [options] [-r | -a]",
@@@ -31,7 -32,7 +32,7 @@@ static unsigned char head_sha1[20]
  
  static int branch_track = 1;
  
 -static int branch_use_color;
 +static int branch_use_color = -1;
  static char branch_colors[][COLOR_MAXLEN] = {
        "\033[m",       /* reset */
        "",             /* PLAIN (normal) */
@@@ -70,21 -71,18 +71,21 @@@ static int git_branch_config(const cha
        }
        if (!prefixcmp(var, "color.branch.")) {
                int slot = parse_branch_color_slot(var, 13);
 +              if (!value)
 +                      return config_error_nonbool(var);
                color_parse(value, var, branch_colors[slot]);
                return 0;
        }
 -      if (!strcmp(var, "branch.autosetupmerge"))
 -                      branch_track = git_config_bool(var, value);
 -
 -      return git_default_config(var, value);
 +      if (!strcmp(var, "branch.autosetupmerge")) {
 +              branch_track = git_config_bool(var, value);
 +              return 0;
 +      }
 +      return git_color_default_config(var, value);
  }
  
  static const char *branch_get_color(enum color_branch ix)
  {
 -      if (branch_use_color)
 +      if (branch_use_color > 0)
                return branch_colors[ix];
        return "";
  }
@@@ -359,141 -357,6 +360,6 @@@ static void print_ref_list(int kinds, i
        free_ref_list(&ref_list);
  }
  
- struct tracking {
-       struct refspec spec;
-       char *src;
-       const char *remote;
-       int matches;
- };
- static int find_tracked_branch(struct remote *remote, void *priv)
- {
-       struct tracking *tracking = priv;
-       if (!remote_find_tracking(remote, &tracking->spec)) {
-               if (++tracking->matches == 1) {
-                       tracking->src = tracking->spec.src;
-                       tracking->remote = remote->name;
-               } else {
-                       free(tracking->spec.src);
-                       if (tracking->src) {
-                               free(tracking->src);
-                               tracking->src = NULL;
-                       }
-               }
-               tracking->spec.src = NULL;
-       }
-       return 0;
- }
- /*
-  * This is called when new_ref is branched off of orig_ref, and tries
-  * to infer the settings for branch.<new_ref>.{remote,merge} from the
-  * config.
-  */
- static int setup_tracking(const char *new_ref, const char *orig_ref)
- {
-       char key[1024];
-       struct tracking tracking;
-       if (strlen(new_ref) > 1024 - 7 - 7 - 1)
-               return error("Tracking not set up: name too long: %s",
-                               new_ref);
-       memset(&tracking, 0, sizeof(tracking));
-       tracking.spec.dst = (char *)orig_ref;
-       if (for_each_remote(find_tracked_branch, &tracking) ||
-                       !tracking.matches)
-               return 1;
-       if (tracking.matches > 1)
-               return error("Not tracking: ambiguous information for ref %s",
-                               orig_ref);
-       if (tracking.matches == 1) {
-               sprintf(key, "branch.%s.remote", new_ref);
-               git_config_set(key, tracking.remote ?  tracking.remote : ".");
-               sprintf(key, "branch.%s.merge", new_ref);
-               git_config_set(key, tracking.src);
-               free(tracking.src);
-               printf("Branch %s set up to track remote branch %s.\n",
-                              new_ref, orig_ref);
-       }
-       return 0;
- }
- static void create_branch(const char *name, const char *start_name,
-                         int force, int reflog, int track)
- {
-       struct ref_lock *lock;
-       struct commit *commit;
-       unsigned char sha1[20];
-       char *real_ref, ref[PATH_MAX], msg[PATH_MAX + 20];
-       int forcing = 0;
-       snprintf(ref, sizeof ref, "refs/heads/%s", name);
-       if (check_ref_format(ref))
-               die("'%s' is not a valid branch name.", name);
-       if (resolve_ref(ref, sha1, 1, NULL)) {
-               if (!force)
-                       die("A branch named '%s' already exists.", name);
-               else if (!is_bare_repository() && !strcmp(head, name))
-                       die("Cannot force update the current branch.");
-               forcing = 1;
-       }
-       real_ref = NULL;
-       if (get_sha1(start_name, sha1))
-               die("Not a valid object name: '%s'.", start_name);
-       switch (dwim_ref(start_name, strlen(start_name), sha1, &real_ref)) {
-       case 0:
-               /* Not branching from any existing branch */
-               real_ref = NULL;
-               break;
-       case 1:
-               /* Unique completion -- good */
-               break;
-       default:
-               die("Ambiguous object name: '%s'.", start_name);
-               break;
-       }
-       if ((commit = lookup_commit_reference(sha1)) == NULL)
-               die("Not a valid branch point: '%s'.", start_name);
-       hashcpy(sha1, commit->object.sha1);
-       lock = lock_any_ref_for_update(ref, NULL, 0);
-       if (!lock)
-               die("Failed to lock ref for update: %s.", strerror(errno));
-       if (reflog)
-               log_all_ref_updates = 1;
-       if (forcing)
-               snprintf(msg, sizeof msg, "branch: Reset from %s",
-                        start_name);
-       else
-               snprintf(msg, sizeof msg, "branch: Created from %s",
-                        start_name);
-       /* When branching off a remote branch, set up so that git-pull
-          automatically merges from there.  So far, this is only done for
-          remotes registered via .git/config.  */
-       if (real_ref && track)
-               setup_tracking(name, real_ref);
-       if (write_ref_sha1(lock, sha1, msg) < 0)
-               die("Failed to write ref: %s.", strerror(errno));
-       if (real_ref)
-               free(real_ref);
- }
  static void rename_branch(const char *oldname, const char *newname, int force)
  {
        char oldref[PATH_MAX], newref[PATH_MAX], logmsg[PATH_MAX*2 + 100];
@@@ -588,10 -451,6 +454,10 @@@ int cmd_branch(int argc, const char **a
        };
  
        git_config(git_branch_config);
 +
 +      if (branch_use_color == -1)
 +              branch_use_color = git_use_color_default;
 +
        track = branch_track;
        argc = parse_options(argc, argv, options, builtin_branch_usage, 0);
        if (!!delete + !!rename + !!force_create > 1)
        else if (rename && (argc == 2))
                rename_branch(argv[0], argv[1], rename > 1);
        else if (argc <= 2)
-               create_branch(argv[0], (argc == 2) ? argv[1] : head,
+               create_branch(head, argv[0], (argc == 2) ? argv[1] : head,
                              force_create, reflog, track);
        else
                usage_with_options(builtin_branch_usage, options);
diff --combined builtin-commit.c
index 065e1f7b7fbf426210d08062800ed81448a30d4a,5b5b7c0f4df81f4200707e0cbe688b3873443125..f49c22e64255225e492614bb628c1d1776521424
@@@ -7,7 -7,6 +7,7 @@@
  
  #include "cache.h"
  #include "cache-tree.h"
 +#include "color.h"
  #include "dir.h"
  #include "builtin.h"
  #include "diff.h"
@@@ -123,23 -122,19 +123,23 @@@ static void rollback_index_files(void
        }
  }
  
 -static void commit_index_files(void)
 +static int commit_index_files(void)
  {
 +      int err = 0;
 +
        switch (commit_style) {
        case COMMIT_AS_IS:
                break; /* nothing to do */
        case COMMIT_NORMAL:
 -              commit_lock_file(&index_lock);
 +              err = commit_lock_file(&index_lock);
                break;
        case COMMIT_PARTIAL:
 -              commit_lock_file(&index_lock);
 +              err = commit_lock_file(&index_lock);
                rollback_lock_file(&false_lock);
                break;
        }
 +
 +      return err;
  }
  
  /*
@@@ -205,7 -200,8 +205,8 @@@ static void create_base_index(void
                die("failed to unpack HEAD tree object");
        parse_tree(tree);
        init_tree_desc(&t, tree->buffer, tree->size);
-       unpack_trees(1, &t, &opts);
+       if (unpack_trees(1, &t, &opts))
+               exit(128); /* We've already reported the error, finish dying */
  }
  
  static char *prepare_index(int argc, const char **argv, const char *prefix)
        if (write_cache(fd, active_cache, active_nr) ||
            close_lock_file(&false_lock))
                die("unable to write temporary index file");
 +
 +      discard_cache();
 +      read_cache_from(false_lock.filename);
 +
        return false_lock.filename;
  }
  
@@@ -348,107 -340,45 +349,107 @@@ static int run_status(FILE *fp, const c
        return s.commitable;
  }
  
 +static int run_hook(const char *index_file, const char *name, ...)
 +{
 +      struct child_process hook;
 +      const char *argv[10], *env[2];
 +      char index[PATH_MAX];
 +      va_list args;
 +      int i;
 +
 +      va_start(args, name);
 +      argv[0] = git_path("hooks/%s", name);
 +      i = 0;
 +      do {
 +              if (++i >= ARRAY_SIZE(argv))
 +                      die ("run_hook(): too many arguments");
 +              argv[i] = va_arg(args, const char *);
 +      } while (argv[i]);
 +      va_end(args);
 +
 +      snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 +      env[0] = index;
 +      env[1] = NULL;
 +
 +      if (access(argv[0], X_OK) < 0)
 +              return 0;
 +
 +      memset(&hook, 0, sizeof(hook));
 +      hook.argv = argv;
 +      hook.no_stdin = 1;
 +      hook.stdout_to_stderr = 1;
 +      hook.env = env;
 +
 +      return run_command(&hook);
 +}
 +
 +static int is_a_merge(const unsigned char *sha1)
 +{
 +      struct commit *commit = lookup_commit(sha1);
 +      if (!commit || parse_commit(commit))
 +              die("could not parse HEAD commit");
 +      return !!(commit->parents && commit->parents->next);
 +}
 +
  static const char sign_off_header[] = "Signed-off-by: ";
  
 -static int prepare_log_message(const char *index_file, const char *prefix)
 +static int prepare_to_commit(const char *index_file, const char *prefix)
  {
        struct stat statbuf;
        int commitable, saved_color_setting;
        struct strbuf sb;
        char *buffer;
        FILE *fp;
 +      const char *hook_arg1 = NULL;
 +      const char *hook_arg2 = NULL;
 +
 +      if (!no_verify && run_hook(index_file, "pre-commit", NULL))
 +              return 0;
  
        strbuf_init(&sb, 0);
        if (message.len) {
                strbuf_addbuf(&sb, &message);
 +              hook_arg1 = "message";
        } else if (logfile && !strcmp(logfile, "-")) {
                if (isatty(0))
                        fprintf(stderr, "(reading log message from standard input)\n");
                if (strbuf_read(&sb, 0, 0) < 0)
                        die("could not read log from standard input");
 +              hook_arg1 = "message";
        } else if (logfile) {
                if (strbuf_read_file(&sb, logfile, 0) < 0)
                        die("could not read log file '%s': %s",
                            logfile, strerror(errno));
 +              hook_arg1 = "message";
        } else if (use_message) {
                buffer = strstr(use_message_buffer, "\n\n");
                if (!buffer || buffer[2] == '\0')
                        die("commit has empty message");
                strbuf_add(&sb, buffer + 2, strlen(buffer + 2));
 +              hook_arg1 = "commit";
 +              hook_arg2 = use_message;
        } else if (!stat(git_path("MERGE_MSG"), &statbuf)) {
                if (strbuf_read_file(&sb, git_path("MERGE_MSG"), 0) < 0)
                        die("could not read MERGE_MSG: %s", strerror(errno));
 +              hook_arg1 = "merge";
        } else if (!stat(git_path("SQUASH_MSG"), &statbuf)) {
                if (strbuf_read_file(&sb, git_path("SQUASH_MSG"), 0) < 0)
                        die("could not read SQUASH_MSG: %s", strerror(errno));
 +              hook_arg1 = "squash";
        } else if (template_file && !stat(template_file, &statbuf)) {
                if (strbuf_read_file(&sb, template_file, 0) < 0)
                        die("could not read %s: %s",
                            template_file, strerror(errno));
 +              hook_arg1 = "template";
        }
  
 +      /*
 +       * This final case does not modify the template message,
 +       * it just sets the argument to the prepare-commit-msg hook.
 +       */
 +      else if (in_merge)
 +              hook_arg1 = "merge";
 +
        fp = fopen(git_path(commit_editmsg), "w");
        if (fp == NULL)
                die("could not open %s", git_path(commit_editmsg));
  
        strbuf_release(&sb);
  
 -      if (!use_editor) {
 +      if (use_editor) {
 +              if (in_merge)
 +                      fprintf(fp,
 +                              "#\n"
 +                              "# It looks like you may be committing a MERGE.\n"
 +                              "# If this is not correct, please remove the file\n"
 +                              "#      %s\n"
 +                              "# and try again.\n"
 +                              "#\n",
 +                              git_path("MERGE_HEAD"));
 +
 +              fprintf(fp,
 +                      "\n"
 +                      "# Please enter the commit message for your changes.\n"
 +                      "# (Comment lines starting with '#' will ");
 +              if (cleanup_mode == CLEANUP_ALL)
 +                      fprintf(fp, "not be included)\n");
 +              else /* CLEANUP_SPACE, that is. */
 +                      fprintf(fp, "be kept.\n"
 +                              "# You can remove them yourself if you want to)\n");
 +              if (only_include_assumed)
 +                      fprintf(fp, "# %s\n", only_include_assumed);
 +
 +              saved_color_setting = wt_status_use_color;
 +              wt_status_use_color = 0;
 +              commitable = run_status(fp, index_file, prefix, 1);
 +              wt_status_use_color = saved_color_setting;
 +      } else {
                struct rev_info rev;
                unsigned char sha1[20];
                const char *parent = "HEAD";
  
 -              fclose(fp);
 -
                if (!active_nr && read_cache() < 0)
                        die("Cannot read index");
  
                        parent = "HEAD^1";
  
                if (get_sha1(parent, sha1))
 -                      return !!active_nr;
 +                      commitable = !!active_nr;
 +              else {
 +                      init_revisions(&rev, "");
 +                      rev.abbrev = 0;
 +                      setup_revisions(0, NULL, &rev, parent);
 +                      DIFF_OPT_SET(&rev.diffopt, QUIET);
 +                      DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
 +                      run_diff_index(&rev, 1 /* cached */);
 +
 +                      commitable = !!DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES);
 +              }
 +      }
  
 -              init_revisions(&rev, "");
 -              rev.abbrev = 0;
 -              setup_revisions(0, NULL, &rev, parent);
 -              DIFF_OPT_SET(&rev.diffopt, QUIET);
 -              DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
 -              run_diff_index(&rev, 1 /* cached */);
 +      fclose(fp);
  
 -              return !!DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES);
 +      if (!commitable && !in_merge && !allow_empty &&
 +          !(amend && is_a_merge(head_sha1))) {
 +              run_status(stdout, index_file, prefix, 0);
 +              unlink(commit_editmsg);
 +              return 0;
        }
  
 -      if (in_merge)
 -              fprintf(fp,
 -                      "#\n"
 -                      "# It looks like you may be committing a MERGE.\n"
 -                      "# If this is not correct, please remove the file\n"
 -                      "#      %s\n"
 -                      "# and try again.\n"
 -                      "#\n",
 -                      git_path("MERGE_HEAD"));
 -
 -      fprintf(fp,
 -              "\n"
 -              "# Please enter the commit message for your changes.\n"
 -              "# (Comment lines starting with '#' will ");
 -      if (cleanup_mode == CLEANUP_ALL)
 -              fprintf(fp, "not be included)\n");
 -      else /* CLEANUP_SPACE, that is. */
 -              fprintf(fp, "be kept.\n"
 -                      "# You can remove them yourself if you want to)\n");
 -      if (only_include_assumed)
 -              fprintf(fp, "# %s\n", only_include_assumed);
 -
 -      saved_color_setting = wt_status_use_color;
 -      wt_status_use_color = 0;
 -      commitable = run_status(fp, index_file, prefix, 1);
 -      wt_status_use_color = saved_color_setting;
 +      /*
 +       * Re-read the index as pre-commit hook could have updated it,
 +       * and write it out as a tree.  We must do this before we invoke
 +       * the editor and after we invoke run_status above.
 +       */
 +      discard_cache();
 +      read_cache_from(index_file);
 +      if (!active_cache_tree)
 +              active_cache_tree = cache_tree();
 +      if (cache_tree_update(active_cache_tree,
 +                            active_cache, active_nr, 0, 0) < 0) {
 +              error("Error building trees");
 +              return 0;
 +      }
  
 -      fclose(fp);
 +      if (run_hook(index_file, "prepare-commit-msg",
 +                   git_path(commit_editmsg), hook_arg1, hook_arg2, NULL))
 +              return 0;
  
 -      return commitable;
 +      if (use_editor) {
 +              char index[PATH_MAX];
 +              const char *env[2] = { index, NULL };
 +              snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 +              launch_editor(git_path(commit_editmsg), NULL, env);
 +      }
 +
 +      if (!no_verify &&
 +          run_hook(index_file, "commit-msg", git_path(commit_editmsg), NULL)) {
 +              return 0;
 +      }
 +
 +      return 1;
  }
  
  /*
@@@ -669,8 -562,6 +670,8 @@@ static int parse_and_validate_options(i
                use_editor = 0;
        if (edit_flag)
                use_editor = 1;
 +      if (!use_editor)
 +              setenv("GIT_EDITOR", ":", 1);
  
        if (get_sha1("HEAD", head_sha1))
                initial_commit = 1;
  
                if (get_sha1(use_message, sha1))
                        die("could not lookup commit %s", use_message);
 -              commit = lookup_commit(sha1);
 +              commit = lookup_commit_reference(sha1);
                if (!commit || parse_commit(commit))
                        die("could not parse commit %s", use_message);
  
@@@ -772,9 -663,6 +773,9 @@@ int cmd_status(int argc, const char **a
  
        git_config(git_status_config);
  
 +      if (wt_status_use_color == -1)
 +              wt_status_use_color = git_use_color_default;
 +
        argc = parse_and_validate_options(argc, argv, builtin_status_usage);
  
        index_file = prepare_index(argc, argv, prefix);
        return commitable ? 0 : 1;
  }
  
 -static int run_hook(const char *index_file, const char *name, const char *arg)
 -{
 -      struct child_process hook;
 -      const char *argv[3], *env[2];
 -      char index[PATH_MAX];
 -
 -      argv[0] = git_path("hooks/%s", name);
 -      argv[1] = arg;
 -      argv[2] = NULL;
 -      snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 -      env[0] = index;
 -      env[1] = NULL;
 -
 -      if (access(argv[0], X_OK) < 0)
 -              return 0;
 -
 -      memset(&hook, 0, sizeof(hook));
 -      hook.argv = argv;
 -      hook.no_stdin = 1;
 -      hook.stdout_to_stderr = 1;
 -      hook.env = env;
 -
 -      return run_command(&hook);
 -}
 -
  static void print_summary(const char *prefix, const unsigned char *sha1)
  {
        struct rev_info rev;
  int git_commit_config(const char *k, const char *v)
  {
        if (!strcmp(k, "commit.template")) {
 +              if (!v)
 +                      return config_error_nonbool(v);
                template_file = xstrdup(v);
                return 0;
        }
        return git_status_config(k, v);
  }
  
 -static int is_a_merge(const unsigned char *sha1)
 -{
 -      struct commit *commit = lookup_commit(sha1);
 -      if (!commit || parse_commit(commit))
 -              die("could not parse HEAD commit");
 -      return !!(commit->parents && commit->parents->next);
 -}
 -
  static const char commit_utf8_warn[] =
  "Warning: commit message does not conform to UTF-8.\n"
  "You may want to amend it after fixing the message, or set the config\n"
@@@ -867,13 -786,33 +868,13 @@@ int cmd_commit(int argc, const char **a
  
        index_file = prepare_index(argc, argv, prefix);
  
 -      if (!no_verify && run_hook(index_file, "pre-commit", NULL)) {
 +      /* Set up everything for writing the commit object.  This includes
 +         running hooks, writing the trees, and interacting with the user.  */
 +      if (!prepare_to_commit(index_file, prefix)) {
                rollback_index_files();
                return 1;
        }
  
 -      if (!prepare_log_message(index_file, prefix) && !in_merge &&
 -          !allow_empty && !(amend && is_a_merge(head_sha1))) {
 -              run_status(stdout, index_file, prefix, 0);
 -              rollback_index_files();
 -              unlink(commit_editmsg);
 -              return 1;
 -      }
 -
 -      /*
 -       * Re-read the index as pre-commit hook could have updated it,
 -       * and write it out as a tree.
 -       */
 -      discard_cache();
 -      read_cache_from(index_file);
 -      if (!active_cache_tree)
 -              active_cache_tree = cache_tree();
 -      if (cache_tree_update(active_cache_tree,
 -                            active_cache, active_nr, 0, 0) < 0) {
 -              rollback_index_files();
 -              die("Error building trees");
 -      }
 -
        /*
         * The commit object
         */
                strbuf_addf(&sb, "encoding %s\n", git_commit_encoding);
        strbuf_addch(&sb, '\n');
  
 -      /* Get the commit message and validate it */
 +      /* Finally, get the commit message */
        header_len = sb.len;
 -      if (use_editor) {
 -              char index[PATH_MAX];
 -              const char *env[2] = { index, NULL };
 -              snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 -              launch_editor(git_path(commit_editmsg), NULL, env);
 -      }
 -      if (!no_verify &&
 -          run_hook(index_file, "commit-msg", git_path(commit_editmsg))) {
 -              rollback_index_files();
 -              exit(1);
 -      }
        if (strbuf_read_file(&sb, git_path(commit_editmsg), 0) < 0) {
                rollback_index_files();
                die("could not read commit message");
  
        unlink(git_path("MERGE_HEAD"));
        unlink(git_path("MERGE_MSG"));
 +      unlink(git_path("SQUASH_MSG"));
  
 -      commit_index_files();
 +      if (commit_index_files())
 +              die ("Repository has been updated, but unable to write\n"
 +                   "new_index file. Check that disk is not full or quota is\n"
 +                   "not exceeded, and then \"git reset HEAD\" to recover.");
  
        rerere();
        run_hook(get_index_file(), "post-commit", NULL);
index 0000000000000000000000000000000000000000,558a58e4d3aaff6e66f25220b30ea9749b50be08..6fe4102c0cfb29031f7fdce68ca4d1937e2fefd7
mode 000000,100644..100644
--- /dev/null
@@@ -1,0 -1,1751 +1,1754 @@@
 -              if (value)
 -                      default_ll_merge = strdup(value);
+ /*
+  * Recursive Merge algorithm stolen from git-merge-recursive.py by
+  * Fredrik Kuivinen.
+  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
+  */
+ #include "cache.h"
+ #include "cache-tree.h"
+ #include "commit.h"
+ #include "blob.h"
+ #include "builtin.h"
+ #include "tree-walk.h"
+ #include "diff.h"
+ #include "diffcore.h"
+ #include "run-command.h"
+ #include "tag.h"
+ #include "unpack-trees.h"
+ #include "path-list.h"
+ #include "xdiff-interface.h"
+ #include "interpolate.h"
+ #include "attr.h"
+ #include "merge-recursive.h"
+ static int subtree_merge;
+ static struct tree *shift_tree_object(struct tree *one, struct tree *two)
+ {
+       unsigned char shifted[20];
+       /*
+        * NEEDSWORK: this limits the recursion depth to hardcoded
+        * value '2' to avoid excessive overhead.
+        */
+       shift_tree(one->object.sha1, two->object.sha1, shifted, 2);
+       if (!hashcmp(two->object.sha1, shifted))
+               return two;
+       return lookup_tree(shifted);
+ }
+ /*
+  * A virtual commit has
+  * - (const char *)commit->util set to the name, and
+  * - *(int *)commit->object.sha1 set to the virtual id.
+  */
+ static unsigned commit_list_count(const struct commit_list *l)
+ {
+       unsigned c = 0;
+       for (; l; l = l->next )
+               c++;
+       return c;
+ }
+ static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
+ {
+       struct commit *commit = xcalloc(1, sizeof(struct commit));
+       static unsigned virtual_id = 1;
+       commit->tree = tree;
+       commit->util = (void*)comment;
+       *(int*)commit->object.sha1 = virtual_id++;
+       /* avoid warnings */
+       commit->object.parsed = 1;
+       return commit;
+ }
+ /*
+  * Since we use get_tree_entry(), which does not put the read object into
+  * the object pool, we cannot rely on a == b.
+  */
+ static int sha_eq(const unsigned char *a, const unsigned char *b)
+ {
+       if (!a && !b)
+               return 2;
+       return a && b && hashcmp(a, b) == 0;
+ }
+ /*
+  * Since we want to write the index eventually, we cannot reuse the index
+  * for these (temporary) data.
+  */
+ struct stage_data
+ {
+       struct
+       {
+               unsigned mode;
+               unsigned char sha[20];
+       } stages[4];
+       unsigned processed:1;
+ };
+ static struct path_list current_file_set = {NULL, 0, 0, 1};
+ static struct path_list current_directory_set = {NULL, 0, 0, 1};
+ static int call_depth = 0;
+ static int verbosity = 2;
+ static int rename_limit = -1;
+ static int buffer_output = 1;
+ static struct strbuf obuf = STRBUF_INIT;
+ static int show(int v)
+ {
+       return (!call_depth && verbosity >= v) || verbosity >= 5;
+ }
+ static void flush_output(void)
+ {
+       if (obuf.len) {
+               fputs(obuf.buf, stdout);
+               strbuf_reset(&obuf);
+       }
+ }
+ static void output(int v, const char *fmt, ...)
+ {
+       int len;
+       va_list ap;
+       if (!show(v))
+               return;
+       strbuf_grow(&obuf, call_depth * 2 + 2);
+       memset(obuf.buf + obuf.len, ' ', call_depth * 2);
+       strbuf_setlen(&obuf, obuf.len + call_depth * 2);
+       va_start(ap, fmt);
+       len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
+       va_end(ap);
+       if (len < 0)
+               len = 0;
+       if (len >= strbuf_avail(&obuf)) {
+               strbuf_grow(&obuf, len + 2);
+               va_start(ap, fmt);
+               len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
+               va_end(ap);
+               if (len >= strbuf_avail(&obuf)) {
+                       die("this should not happen, your snprintf is broken");
+               }
+       }
+       strbuf_setlen(&obuf, obuf.len + len);
+       strbuf_add(&obuf, "\n", 1);
+       if (!buffer_output)
+               flush_output();
+ }
+ static void output_commit_title(struct commit *commit)
+ {
+       int i;
+       flush_output();
+       for (i = call_depth; i--;)
+               fputs("  ", stdout);
+       if (commit->util)
+               printf("virtual %s\n", (char *)commit->util);
+       else {
+               printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
+               if (parse_commit(commit) != 0)
+                       printf("(bad commit)\n");
+               else {
+                       const char *s;
+                       int len;
+                       for (s = commit->buffer; *s; s++)
+                               if (*s == '\n' && s[1] == '\n') {
+                                       s += 2;
+                                       break;
+                               }
+                       for (len = 0; s[len] && '\n' != s[len]; len++)
+                               ; /* do nothing */
+                       printf("%.*s\n", len, s);
+               }
+       }
+ }
+ static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
+               const char *path, int stage, int refresh, int options)
+ {
+       struct cache_entry *ce;
+       ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
+       if (!ce)
+               return error("addinfo_cache failed for path '%s'", path);
+       return add_cache_entry(ce, options);
+ }
+ /*
+  * This is a global variable which is used in a number of places but
+  * only written to in the 'merge' function.
+  *
+  * index_only == 1    => Don't leave any non-stage 0 entries in the cache and
+  *                       don't update the working directory.
+  *               0    => Leave unmerged entries in the cache and update
+  *                       the working directory.
+  */
+ static int index_only = 0;
+ static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
+ {
+       parse_tree(tree);
+       init_tree_desc(desc, tree->buffer, tree->size);
+ }
+ static int git_merge_trees(int index_only,
+                          struct tree *common,
+                          struct tree *head,
+                          struct tree *merge)
+ {
+       int rc;
+       struct tree_desc t[3];
+       struct unpack_trees_options opts;
+       memset(&opts, 0, sizeof(opts));
+       if (index_only)
+               opts.index_only = 1;
+       else
+               opts.update = 1;
+       opts.merge = 1;
+       opts.head_idx = 2;
+       opts.fn = threeway_merge;
+       init_tree_desc_from_tree(t+0, common);
+       init_tree_desc_from_tree(t+1, head);
+       init_tree_desc_from_tree(t+2, merge);
+       rc = unpack_trees(3, t, &opts);
+       cache_tree_free(&active_cache_tree);
+       return rc;
+ }
+ struct tree *write_tree_from_memory(void)
+ {
+       struct tree *result = NULL;
+       if (unmerged_cache()) {
+               int i;
+               output(0, "There are unmerged index entries:");
+               for (i = 0; i < active_nr; i++) {
+                       struct cache_entry *ce = active_cache[i];
+                       if (ce_stage(ce))
+                               output(0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
+               }
+               return NULL;
+       }
+       if (!active_cache_tree)
+               active_cache_tree = cache_tree();
+       if (!cache_tree_fully_valid(active_cache_tree) &&
+           cache_tree_update(active_cache_tree,
+                             active_cache, active_nr, 0, 0) < 0)
+               die("error building trees");
+       result = lookup_tree(active_cache_tree->sha1);
+       return result;
+ }
+ static int save_files_dirs(const unsigned char *sha1,
+               const char *base, int baselen, const char *path,
+               unsigned int mode, int stage)
+ {
+       int len = strlen(path);
+       char *newpath = xmalloc(baselen + len + 1);
+       memcpy(newpath, base, baselen);
+       memcpy(newpath + baselen, path, len);
+       newpath[baselen + len] = '\0';
+       if (S_ISDIR(mode))
+               path_list_insert(newpath, &current_directory_set);
+       else
+               path_list_insert(newpath, &current_file_set);
+       free(newpath);
+       return READ_TREE_RECURSIVE;
+ }
+ static int get_files_dirs(struct tree *tree)
+ {
+       int n;
+       if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs) != 0)
+               return 0;
+       n = current_file_set.nr + current_directory_set.nr;
+       return n;
+ }
+ /*
+  * Returns an index_entry instance which doesn't have to correspond to
+  * a real cache entry in Git's index.
+  */
+ static struct stage_data *insert_stage_data(const char *path,
+               struct tree *o, struct tree *a, struct tree *b,
+               struct path_list *entries)
+ {
+       struct path_list_item *item;
+       struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
+       get_tree_entry(o->object.sha1, path,
+                       e->stages[1].sha, &e->stages[1].mode);
+       get_tree_entry(a->object.sha1, path,
+                       e->stages[2].sha, &e->stages[2].mode);
+       get_tree_entry(b->object.sha1, path,
+                       e->stages[3].sha, &e->stages[3].mode);
+       item = path_list_insert(path, entries);
+       item->util = e;
+       return e;
+ }
+ /*
+  * Create a dictionary mapping file names to stage_data objects. The
+  * dictionary contains one entry for every path with a non-zero stage entry.
+  */
+ static struct path_list *get_unmerged(void)
+ {
+       struct path_list *unmerged = xcalloc(1, sizeof(struct path_list));
+       int i;
+       unmerged->strdup_paths = 1;
+       for (i = 0; i < active_nr; i++) {
+               struct path_list_item *item;
+               struct stage_data *e;
+               struct cache_entry *ce = active_cache[i];
+               if (!ce_stage(ce))
+                       continue;
+               item = path_list_lookup(ce->name, unmerged);
+               if (!item) {
+                       item = path_list_insert(ce->name, unmerged);
+                       item->util = xcalloc(1, sizeof(struct stage_data));
+               }
+               e = item->util;
+               e->stages[ce_stage(ce)].mode = ce->ce_mode;
+               hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
+       }
+       return unmerged;
+ }
+ struct rename
+ {
+       struct diff_filepair *pair;
+       struct stage_data *src_entry;
+       struct stage_data *dst_entry;
+       unsigned processed:1;
+ };
+ /*
+  * Get information of all renames which occurred between 'o_tree' and
+  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
+  * 'b_tree') to be able to associate the correct cache entries with
+  * the rename information. 'tree' is always equal to either a_tree or b_tree.
+  */
+ static struct path_list *get_renames(struct tree *tree,
+                                       struct tree *o_tree,
+                                       struct tree *a_tree,
+                                       struct tree *b_tree,
+                                       struct path_list *entries)
+ {
+       int i;
+       struct path_list *renames;
+       struct diff_options opts;
+       renames = xcalloc(1, sizeof(struct path_list));
+       diff_setup(&opts);
+       DIFF_OPT_SET(&opts, RECURSIVE);
+       opts.detect_rename = DIFF_DETECT_RENAME;
+       opts.rename_limit = rename_limit;
+       opts.output_format = DIFF_FORMAT_NO_OUTPUT;
+       if (diff_setup_done(&opts) < 0)
+               die("diff setup failed");
+       diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
+       diffcore_std(&opts);
+       for (i = 0; i < diff_queued_diff.nr; ++i) {
+               struct path_list_item *item;
+               struct rename *re;
+               struct diff_filepair *pair = diff_queued_diff.queue[i];
+               if (pair->status != 'R') {
+                       diff_free_filepair(pair);
+                       continue;
+               }
+               re = xmalloc(sizeof(*re));
+               re->processed = 0;
+               re->pair = pair;
+               item = path_list_lookup(re->pair->one->path, entries);
+               if (!item)
+                       re->src_entry = insert_stage_data(re->pair->one->path,
+                                       o_tree, a_tree, b_tree, entries);
+               else
+                       re->src_entry = item->util;
+               item = path_list_lookup(re->pair->two->path, entries);
+               if (!item)
+                       re->dst_entry = insert_stage_data(re->pair->two->path,
+                                       o_tree, a_tree, b_tree, entries);
+               else
+                       re->dst_entry = item->util;
+               item = path_list_insert(pair->one->path, renames);
+               item->util = re;
+       }
+       opts.output_format = DIFF_FORMAT_NO_OUTPUT;
+       diff_queued_diff.nr = 0;
+       diff_flush(&opts);
+       return renames;
+ }
+ static int update_stages(const char *path, struct diff_filespec *o,
+                        struct diff_filespec *a, struct diff_filespec *b,
+                        int clear)
+ {
+       int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
+       if (clear)
+               if (remove_file_from_cache(path))
+                       return -1;
+       if (o)
+               if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
+                       return -1;
+       if (a)
+               if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
+                       return -1;
+       if (b)
+               if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
+                       return -1;
+       return 0;
+ }
+ static int remove_path(const char *name)
+ {
+       int ret;
+       char *slash, *dirs;
+       ret = unlink(name);
+       if (ret)
+               return ret;
+       dirs = xstrdup(name);
+       while ((slash = strrchr(name, '/'))) {
+               *slash = '\0';
+               if (rmdir(name) != 0)
+                       break;
+       }
+       free(dirs);
+       return ret;
+ }
+ static int remove_file(int clean, const char *path, int no_wd)
+ {
+       int update_cache = index_only || clean;
+       int update_working_directory = !index_only && !no_wd;
+       if (update_cache) {
+               if (remove_file_from_cache(path))
+                       return -1;
+       }
+       if (update_working_directory) {
+               unlink(path);
+               if (errno != ENOENT || errno != EISDIR)
+                       return -1;
+               remove_path(path);
+       }
+       return 0;
+ }
+ static char *unique_path(const char *path, const char *branch)
+ {
+       char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
+       int suffix = 0;
+       struct stat st;
+       char *p = newpath + strlen(path);
+       strcpy(newpath, path);
+       *(p++) = '~';
+       strcpy(p, branch);
+       for (; *p; ++p)
+               if ('/' == *p)
+                       *p = '_';
+       while (path_list_has_path(&current_file_set, newpath) ||
+              path_list_has_path(&current_directory_set, newpath) ||
+              lstat(newpath, &st) == 0)
+               sprintf(p, "_%d", suffix++);
+       path_list_insert(newpath, &current_file_set);
+       return newpath;
+ }
+ static int mkdir_p(const char *path, unsigned long mode)
+ {
+       /* path points to cache entries, so xstrdup before messing with it */
+       char *buf = xstrdup(path);
+       int result = safe_create_leading_directories(buf);
+       free(buf);
+       return result;
+ }
+ static void flush_buffer(int fd, const char *buf, unsigned long size)
+ {
+       while (size > 0) {
+               long ret = write_in_full(fd, buf, size);
+               if (ret < 0) {
+                       /* Ignore epipe */
+                       if (errno == EPIPE)
+                               break;
+                       die("merge-recursive: %s", strerror(errno));
+               } else if (!ret) {
+                       die("merge-recursive: disk full?");
+               }
+               size -= ret;
+               buf += ret;
+       }
+ }
+ static int make_room_for_path(const char *path)
+ {
+       int status;
+       const char *msg = "failed to create path '%s'%s";
+       status = mkdir_p(path, 0777);
+       if (status) {
+               if (status == -3) {
+                       /* something else exists */
+                       error(msg, path, ": perhaps a D/F conflict?");
+                       return -1;
+               }
+               die(msg, path, "");
+       }
+       /* Successful unlink is good.. */
+       if (!unlink(path))
+               return 0;
+       /* .. and so is no existing file */
+       if (errno == ENOENT)
+               return 0;
+       /* .. but not some other error (who really cares what?) */
+       return error(msg, path, ": perhaps a D/F conflict?");
+ }
+ static void update_file_flags(const unsigned char *sha,
+                             unsigned mode,
+                             const char *path,
+                             int update_cache,
+                             int update_wd)
+ {
+       if (index_only)
+               update_wd = 0;
+       if (update_wd) {
+               enum object_type type;
+               void *buf;
+               unsigned long size;
+               if (S_ISGITLINK(mode))
+                       die("cannot read object %s '%s': It is a submodule!",
+                           sha1_to_hex(sha), path);
+               buf = read_sha1_file(sha, &type, &size);
+               if (!buf)
+                       die("cannot read object %s '%s'", sha1_to_hex(sha), path);
+               if (type != OBJ_BLOB)
+                       die("blob expected for %s '%s'", sha1_to_hex(sha), path);
+               if (make_room_for_path(path) < 0) {
+                       update_wd = 0;
+                       goto update_index;
+               }
+               if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
+                       int fd;
+                       if (mode & 0100)
+                               mode = 0777;
+                       else
+                               mode = 0666;
+                       fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
+                       if (fd < 0)
+                               die("failed to open %s: %s", path, strerror(errno));
+                       flush_buffer(fd, buf, size);
+                       close(fd);
+               } else if (S_ISLNK(mode)) {
+                       char *lnk = xmemdupz(buf, size);
+                       mkdir_p(path, 0777);
+                       unlink(path);
+                       symlink(lnk, path);
+                       free(lnk);
+               } else
+                       die("do not know what to do with %06o %s '%s'",
+                           mode, sha1_to_hex(sha), path);
+       }
+  update_index:
+       if (update_cache)
+               add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
+ }
+ static void update_file(int clean,
+                       const unsigned char *sha,
+                       unsigned mode,
+                       const char *path)
+ {
+       update_file_flags(sha, mode, path, index_only || clean, !index_only);
+ }
+ /* Low level file merging, update and removal */
+ struct merge_file_info
+ {
+       unsigned char sha[20];
+       unsigned mode;
+       unsigned clean:1,
+                merge:1;
+ };
+ static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
+ {
+       unsigned long size;
+       enum object_type type;
+       if (!hashcmp(sha1, null_sha1)) {
+               mm->ptr = xstrdup("");
+               mm->size = 0;
+               return;
+       }
+       mm->ptr = read_sha1_file(sha1, &type, &size);
+       if (!mm->ptr || type != OBJ_BLOB)
+               die("unable to read blob object %s", sha1_to_hex(sha1));
+       mm->size = size;
+ }
+ /*
+  * Customizable low-level merge drivers support.
+  */
+ struct ll_merge_driver;
+ typedef int (*ll_merge_fn)(const struct ll_merge_driver *,
+                          const char *path,
+                          mmfile_t *orig,
+                          mmfile_t *src1, const char *name1,
+                          mmfile_t *src2, const char *name2,
+                          mmbuffer_t *result);
+ struct ll_merge_driver {
+       const char *name;
+       const char *description;
+       ll_merge_fn fn;
+       const char *recursive;
+       struct ll_merge_driver *next;
+       char *cmdline;
+ };
+ /*
+  * Built-in low-levels
+  */
+ static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
+                          const char *path_unused,
+                          mmfile_t *orig,
+                          mmfile_t *src1, const char *name1,
+                          mmfile_t *src2, const char *name2,
+                          mmbuffer_t *result)
+ {
+       /*
+        * The tentative merge result is "ours" for the final round,
+        * or common ancestor for an internal merge.  Still return
+        * "conflicted merge" status.
+        */
+       mmfile_t *stolen = index_only ? orig : src1;
+       result->ptr = stolen->ptr;
+       result->size = stolen->size;
+       stolen->ptr = NULL;
+       return 1;
+ }
+ static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
+                       const char *path_unused,
+                       mmfile_t *orig,
+                       mmfile_t *src1, const char *name1,
+                       mmfile_t *src2, const char *name2,
+                       mmbuffer_t *result)
+ {
+       xpparam_t xpp;
+       if (buffer_is_binary(orig->ptr, orig->size) ||
+           buffer_is_binary(src1->ptr, src1->size) ||
+           buffer_is_binary(src2->ptr, src2->size)) {
+               warning("Cannot merge binary files: %s vs. %s\n",
+                       name1, name2);
+               return ll_binary_merge(drv_unused, path_unused,
+                                      orig, src1, name1,
+                                      src2, name2,
+                                      result);
+       }
+       memset(&xpp, 0, sizeof(xpp));
+       return xdl_merge(orig,
+                        src1, name1,
+                        src2, name2,
+                        &xpp, XDL_MERGE_ZEALOUS,
+                        result);
+ }
+ static int ll_union_merge(const struct ll_merge_driver *drv_unused,
+                         const char *path_unused,
+                         mmfile_t *orig,
+                         mmfile_t *src1, const char *name1,
+                         mmfile_t *src2, const char *name2,
+                         mmbuffer_t *result)
+ {
+       char *src, *dst;
+       long size;
+       const int marker_size = 7;
+       int status = ll_xdl_merge(drv_unused, path_unused,
+                                 orig, src1, NULL, src2, NULL, result);
+       if (status <= 0)
+               return status;
+       size = result->size;
+       src = dst = result->ptr;
+       while (size) {
+               char ch;
+               if ((marker_size < size) &&
+                   (*src == '<' || *src == '=' || *src == '>')) {
+                       int i;
+                       ch = *src;
+                       for (i = 0; i < marker_size; i++)
+                               if (src[i] != ch)
+                                       goto not_a_marker;
+                       if (src[marker_size] != '\n')
+                               goto not_a_marker;
+                       src += marker_size + 1;
+                       size -= marker_size + 1;
+                       continue;
+               }
+       not_a_marker:
+               do {
+                       ch = *src++;
+                       *dst++ = ch;
+                       size--;
+               } while (ch != '\n' && size);
+       }
+       result->size = dst - result->ptr;
+       return 0;
+ }
+ #define LL_BINARY_MERGE 0
+ #define LL_TEXT_MERGE 1
+ #define LL_UNION_MERGE 2
+ static struct ll_merge_driver ll_merge_drv[] = {
+       { "binary", "built-in binary merge", ll_binary_merge },
+       { "text", "built-in 3-way text merge", ll_xdl_merge },
+       { "union", "built-in union merge", ll_union_merge },
+ };
+ static void create_temp(mmfile_t *src, char *path)
+ {
+       int fd;
+       strcpy(path, ".merge_file_XXXXXX");
+       fd = xmkstemp(path);
+       if (write_in_full(fd, src->ptr, src->size) != src->size)
+               die("unable to write temp-file");
+       close(fd);
+ }
+ /*
+  * User defined low-level merge driver support.
+  */
+ static int ll_ext_merge(const struct ll_merge_driver *fn,
+                       const char *path,
+                       mmfile_t *orig,
+                       mmfile_t *src1, const char *name1,
+                       mmfile_t *src2, const char *name2,
+                       mmbuffer_t *result)
+ {
+       char temp[3][50];
+       char cmdbuf[2048];
+       struct interp table[] = {
+               { "%O" },
+               { "%A" },
+               { "%B" },
+       };
+       struct child_process child;
+       const char *args[20];
+       int status, fd, i;
+       struct stat st;
+       if (fn->cmdline == NULL)
+               die("custom merge driver %s lacks command line.", fn->name);
+       result->ptr = NULL;
+       result->size = 0;
+       create_temp(orig, temp[0]);
+       create_temp(src1, temp[1]);
+       create_temp(src2, temp[2]);
+       interp_set_entry(table, 0, temp[0]);
+       interp_set_entry(table, 1, temp[1]);
+       interp_set_entry(table, 2, temp[2]);
+       output(1, "merging %s using %s", path,
+              fn->description ? fn->description : fn->name);
+       interpolate(cmdbuf, sizeof(cmdbuf), fn->cmdline, table, 3);
+       memset(&child, 0, sizeof(child));
+       child.argv = args;
+       args[0] = "sh";
+       args[1] = "-c";
+       args[2] = cmdbuf;
+       args[3] = NULL;
+       status = run_command(&child);
+       if (status < -ERR_RUN_COMMAND_FORK)
+               ; /* failure in run-command */
+       else
+               status = -status;
+       fd = open(temp[1], O_RDONLY);
+       if (fd < 0)
+               goto bad;
+       if (fstat(fd, &st))
+               goto close_bad;
+       result->size = st.st_size;
+       result->ptr = xmalloc(result->size + 1);
+       if (read_in_full(fd, result->ptr, result->size) != result->size) {
+               free(result->ptr);
+               result->ptr = NULL;
+               result->size = 0;
+       }
+  close_bad:
+       close(fd);
+  bad:
+       for (i = 0; i < 3; i++)
+               unlink(temp[i]);
+       return status;
+ }
+ /*
+  * merge.default and merge.driver configuration items
+  */
+ static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
+ static const char *default_ll_merge;
+ static int read_merge_config(const char *var, const char *value)
+ {
+       struct ll_merge_driver *fn;
+       const char *ep, *name;
+       int namelen;
+       if (!strcmp(var, "merge.default")) {
 -                      return error("%s: lacks value", var);
++              if (!value)
++                      return config_error_nonbool(var);
++              default_ll_merge = strdup(value);
+               return 0;
+       }
+       /*
+        * We are not interested in anything but "merge.<name>.variable";
+        * especially, we do not want to look at variables such as
+        * "merge.summary", "merge.tool", and "merge.verbosity".
+        */
+       if (prefixcmp(var, "merge.") || (ep = strrchr(var, '.')) == var + 5)
+               return 0;
+       /*
+        * Find existing one as we might be processing merge.<name>.var2
+        * after seeing merge.<name>.var1.
+        */
+       name = var + 6;
+       namelen = ep - name;
+       for (fn = ll_user_merge; fn; fn = fn->next)
+               if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
+                       break;
+       if (!fn) {
+               fn = xcalloc(1, sizeof(struct ll_merge_driver));
+               fn->name = xmemdupz(name, namelen);
+               fn->fn = ll_ext_merge;
+               *ll_user_merge_tail = fn;
+               ll_user_merge_tail = &(fn->next);
+       }
+       ep++;
+       if (!strcmp("name", ep)) {
+               if (!value)
 -                      return error("%s: lacks value", var);
++                      return config_error_nonbool(var);
+               fn->description = strdup(value);
+               return 0;
+       }
+       if (!strcmp("driver", ep)) {
+               if (!value)
 -                      return error("%s: lacks value", var);
++                      return config_error_nonbool(var);
+               /*
+                * merge.<name>.driver specifies the command line:
+                *
+                *      command-line
+                *
+                * The command-line will be interpolated with the following
+                * tokens and is given to the shell:
+                *
+                *    %O - temporary file name for the merge base.
+                *    %A - temporary file name for our version.
+                *    %B - temporary file name for the other branches' version.
+                *
+                * The external merge driver should write the results in the
+                * file named by %A, and signal that it has done with zero exit
+                * status.
+                */
+               fn->cmdline = strdup(value);
+               return 0;
+       }
+       if (!strcmp("recursive", ep)) {
+               if (!value)
++                      return config_error_nonbool(var);
+               fn->recursive = strdup(value);
+               return 0;
+       }
+       return 0;
+ }
+ static void initialize_ll_merge(void)
+ {
+       if (ll_user_merge_tail)
+               return;
+       ll_user_merge_tail = &ll_user_merge;
+       git_config(read_merge_config);
+ }
+ static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
+ {
+       struct ll_merge_driver *fn;
+       const char *name;
+       int i;
+       initialize_ll_merge();
+       if (ATTR_TRUE(merge_attr))
+               return &ll_merge_drv[LL_TEXT_MERGE];
+       else if (ATTR_FALSE(merge_attr))
+               return &ll_merge_drv[LL_BINARY_MERGE];
+       else if (ATTR_UNSET(merge_attr)) {
+               if (!default_ll_merge)
+                       return &ll_merge_drv[LL_TEXT_MERGE];
+               else
+                       name = default_ll_merge;
+       }
+       else
+               name = merge_attr;
+       for (fn = ll_user_merge; fn; fn = fn->next)
+               if (!strcmp(fn->name, name))
+                       return fn;
+       for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
+               if (!strcmp(ll_merge_drv[i].name, name))
+                       return &ll_merge_drv[i];
+       /* default to the 3-way */
+       return &ll_merge_drv[LL_TEXT_MERGE];
+ }
+ static const char *git_path_check_merge(const char *path)
+ {
+       static struct git_attr_check attr_merge_check;
+       if (!attr_merge_check.attr)
+               attr_merge_check.attr = git_attr("merge", 5);
+       if (git_checkattr(path, 1, &attr_merge_check))
+               return NULL;
+       return attr_merge_check.value;
+ }
+ static int ll_merge(mmbuffer_t *result_buf,
+                   struct diff_filespec *o,
+                   struct diff_filespec *a,
+                   struct diff_filespec *b,
+                   const char *branch1,
+                   const char *branch2)
+ {
+       mmfile_t orig, src1, src2;
+       char *name1, *name2;
+       int merge_status;
+       const char *ll_driver_name;
+       const struct ll_merge_driver *driver;
+       name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
+       name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
+       fill_mm(o->sha1, &orig);
+       fill_mm(a->sha1, &src1);
+       fill_mm(b->sha1, &src2);
+       ll_driver_name = git_path_check_merge(a->path);
+       driver = find_ll_merge_driver(ll_driver_name);
+       if (index_only && driver->recursive)
+               driver = find_ll_merge_driver(driver->recursive);
+       merge_status = driver->fn(driver, a->path,
+                                 &orig, &src1, name1, &src2, name2,
+                                 result_buf);
+       free(name1);
+       free(name2);
+       free(orig.ptr);
+       free(src1.ptr);
+       free(src2.ptr);
+       return merge_status;
+ }
+ static struct merge_file_info merge_file(struct diff_filespec *o,
+               struct diff_filespec *a, struct diff_filespec *b,
+               const char *branch1, const char *branch2)
+ {
+       struct merge_file_info result;
+       result.merge = 0;
+       result.clean = 1;
+       if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
+               result.clean = 0;
+               if (S_ISREG(a->mode)) {
+                       result.mode = a->mode;
+                       hashcpy(result.sha, a->sha1);
+               } else {
+                       result.mode = b->mode;
+                       hashcpy(result.sha, b->sha1);
+               }
+       } else {
+               if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
+                       result.merge = 1;
+               result.mode = a->mode == o->mode ? b->mode: a->mode;
+               if (sha_eq(a->sha1, o->sha1))
+                       hashcpy(result.sha, b->sha1);
+               else if (sha_eq(b->sha1, o->sha1))
+                       hashcpy(result.sha, a->sha1);
+               else if (S_ISREG(a->mode)) {
+                       mmbuffer_t result_buf;
+                       int merge_status;
+                       merge_status = ll_merge(&result_buf, o, a, b,
+                                               branch1, branch2);
+                       if ((merge_status < 0) || !result_buf.ptr)
+                               die("Failed to execute internal merge");
+                       if (write_sha1_file(result_buf.ptr, result_buf.size,
+                                           blob_type, result.sha))
+                               die("Unable to add %s to database",
+                                   a->path);
+                       free(result_buf.ptr);
+                       result.clean = (merge_status == 0);
+               } else if (S_ISGITLINK(a->mode)) {
+                       result.clean = 0;
+                       hashcpy(result.sha, a->sha1);
+               } else if (S_ISLNK(a->mode)) {
+                       hashcpy(result.sha, a->sha1);
+                       if (!sha_eq(a->sha1, b->sha1))
+                               result.clean = 0;
+               } else {
+                       die("unsupported object type in the tree");
+               }
+       }
+       return result;
+ }
+ static void conflict_rename_rename(struct rename *ren1,
+                                  const char *branch1,
+                                  struct rename *ren2,
+                                  const char *branch2)
+ {
+       char *del[2];
+       int delp = 0;
+       const char *ren1_dst = ren1->pair->two->path;
+       const char *ren2_dst = ren2->pair->two->path;
+       const char *dst_name1 = ren1_dst;
+       const char *dst_name2 = ren2_dst;
+       if (path_list_has_path(&current_directory_set, ren1_dst)) {
+               dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
+               output(1, "%s is a directory in %s added as %s instead",
+                      ren1_dst, branch2, dst_name1);
+               remove_file(0, ren1_dst, 0);
+       }
+       if (path_list_has_path(&current_directory_set, ren2_dst)) {
+               dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
+               output(1, "%s is a directory in %s added as %s instead",
+                      ren2_dst, branch1, dst_name2);
+               remove_file(0, ren2_dst, 0);
+       }
+       if (index_only) {
+               remove_file_from_cache(dst_name1);
+               remove_file_from_cache(dst_name2);
+               /*
+                * Uncomment to leave the conflicting names in the resulting tree
+                *
+                * update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
+                * update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
+                */
+       } else {
+               update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
+               update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
+       }
+       while (delp--)
+               free(del[delp]);
+ }
+ static void conflict_rename_dir(struct rename *ren1,
+                               const char *branch1)
+ {
+       char *new_path = unique_path(ren1->pair->two->path, branch1);
+       output(1, "Renamed %s to %s instead", ren1->pair->one->path, new_path);
+       remove_file(0, ren1->pair->two->path, 0);
+       update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
+       free(new_path);
+ }
+ static void conflict_rename_rename_2(struct rename *ren1,
+                                    const char *branch1,
+                                    struct rename *ren2,
+                                    const char *branch2)
+ {
+       char *new_path1 = unique_path(ren1->pair->two->path, branch1);
+       char *new_path2 = unique_path(ren2->pair->two->path, branch2);
+       output(1, "Renamed %s to %s and %s to %s instead",
+              ren1->pair->one->path, new_path1,
+              ren2->pair->one->path, new_path2);
+       remove_file(0, ren1->pair->two->path, 0);
+       update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
+       update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
+       free(new_path2);
+       free(new_path1);
+ }
+ static int process_renames(struct path_list *a_renames,
+                          struct path_list *b_renames,
+                          const char *a_branch,
+                          const char *b_branch)
+ {
+       int clean_merge = 1, i, j;
+       struct path_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
+       const struct rename *sre;
+       for (i = 0; i < a_renames->nr; i++) {
+               sre = a_renames->items[i].util;
+               path_list_insert(sre->pair->two->path, &a_by_dst)->util
+                       = sre->dst_entry;
+       }
+       for (i = 0; i < b_renames->nr; i++) {
+               sre = b_renames->items[i].util;
+               path_list_insert(sre->pair->two->path, &b_by_dst)->util
+                       = sre->dst_entry;
+       }
+       for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
+               int compare;
+               char *src;
+               struct path_list *renames1, *renames2, *renames2Dst;
+               struct rename *ren1 = NULL, *ren2 = NULL;
+               const char *branch1, *branch2;
+               const char *ren1_src, *ren1_dst;
+               if (i >= a_renames->nr) {
+                       compare = 1;
+                       ren2 = b_renames->items[j++].util;
+               } else if (j >= b_renames->nr) {
+                       compare = -1;
+                       ren1 = a_renames->items[i++].util;
+               } else {
+                       compare = strcmp(a_renames->items[i].path,
+                                       b_renames->items[j].path);
+                       if (compare <= 0)
+                               ren1 = a_renames->items[i++].util;
+                       if (compare >= 0)
+                               ren2 = b_renames->items[j++].util;
+               }
+               /* TODO: refactor, so that 1/2 are not needed */
+               if (ren1) {
+                       renames1 = a_renames;
+                       renames2 = b_renames;
+                       renames2Dst = &b_by_dst;
+                       branch1 = a_branch;
+                       branch2 = b_branch;
+               } else {
+                       struct rename *tmp;
+                       renames1 = b_renames;
+                       renames2 = a_renames;
+                       renames2Dst = &a_by_dst;
+                       branch1 = b_branch;
+                       branch2 = a_branch;
+                       tmp = ren2;
+                       ren2 = ren1;
+                       ren1 = tmp;
+               }
+               src = ren1->pair->one->path;
+               ren1->dst_entry->processed = 1;
+               ren1->src_entry->processed = 1;
+               if (ren1->processed)
+                       continue;
+               ren1->processed = 1;
+               ren1_src = ren1->pair->one->path;
+               ren1_dst = ren1->pair->two->path;
+               if (ren2) {
+                       const char *ren2_src = ren2->pair->one->path;
+                       const char *ren2_dst = ren2->pair->two->path;
+                       /* Renamed in 1 and renamed in 2 */
+                       if (strcmp(ren1_src, ren2_src) != 0)
+                               die("ren1.src != ren2.src");
+                       ren2->dst_entry->processed = 1;
+                       ren2->processed = 1;
+                       if (strcmp(ren1_dst, ren2_dst) != 0) {
+                               clean_merge = 0;
+                               output(1, "CONFLICT (rename/rename): "
+                                      "Rename \"%s\"->\"%s\" in branch \"%s\" "
+                                      "rename \"%s\"->\"%s\" in \"%s\"%s",
+                                      src, ren1_dst, branch1,
+                                      src, ren2_dst, branch2,
+                                      index_only ? " (left unresolved)": "");
+                               if (index_only) {
+                                       remove_file_from_cache(src);
+                                       update_file(0, ren1->pair->one->sha1,
+                                                   ren1->pair->one->mode, src);
+                               }
+                               conflict_rename_rename(ren1, branch1, ren2, branch2);
+                       } else {
+                               struct merge_file_info mfi;
+                               remove_file(1, ren1_src, 1);
+                               mfi = merge_file(ren1->pair->one,
+                                                ren1->pair->two,
+                                                ren2->pair->two,
+                                                branch1,
+                                                branch2);
+                               if (mfi.merge || !mfi.clean)
+                                       output(1, "Renamed %s->%s", src, ren1_dst);
+                               if (mfi.merge)
+                                       output(2, "Auto-merged %s", ren1_dst);
+                               if (!mfi.clean) {
+                                       output(1, "CONFLICT (content): merge conflict in %s",
+                                              ren1_dst);
+                                       clean_merge = 0;
+                                       if (!index_only)
+                                               update_stages(ren1_dst,
+                                                             ren1->pair->one,
+                                                             ren1->pair->two,
+                                                             ren2->pair->two,
+                                                             1 /* clear */);
+                               }
+                               update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
+                       }
+               } else {
+                       /* Renamed in 1, maybe changed in 2 */
+                       struct path_list_item *item;
+                       /* we only use sha1 and mode of these */
+                       struct diff_filespec src_other, dst_other;
+                       int try_merge, stage = a_renames == renames1 ? 3: 2;
+                       remove_file(1, ren1_src, index_only || stage == 3);
+                       hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
+                       src_other.mode = ren1->src_entry->stages[stage].mode;
+                       hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
+                       dst_other.mode = ren1->dst_entry->stages[stage].mode;
+                       try_merge = 0;
+                       if (path_list_has_path(&current_directory_set, ren1_dst)) {
+                               clean_merge = 0;
+                               output(1, "CONFLICT (rename/directory): Renamed %s->%s in %s "
+                                      " directory %s added in %s",
+                                      ren1_src, ren1_dst, branch1,
+                                      ren1_dst, branch2);
+                               conflict_rename_dir(ren1, branch1);
+                       } else if (sha_eq(src_other.sha1, null_sha1)) {
+                               clean_merge = 0;
+                               output(1, "CONFLICT (rename/delete): Renamed %s->%s in %s "
+                                      "and deleted in %s",
+                                      ren1_src, ren1_dst, branch1,
+                                      branch2);
+                               update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
+                       } else if (!sha_eq(dst_other.sha1, null_sha1)) {
+                               const char *new_path;
+                               clean_merge = 0;
+                               try_merge = 1;
+                               output(1, "CONFLICT (rename/add): Renamed %s->%s in %s. "
+                                      "%s added in %s",
+                                      ren1_src, ren1_dst, branch1,
+                                      ren1_dst, branch2);
+                               new_path = unique_path(ren1_dst, branch2);
+                               output(1, "Added as %s instead", new_path);
+                               update_file(0, dst_other.sha1, dst_other.mode, new_path);
+                       } else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
+                               ren2 = item->util;
+                               clean_merge = 0;
+                               ren2->processed = 1;
+                               output(1, "CONFLICT (rename/rename): Renamed %s->%s in %s. "
+                                      "Renamed %s->%s in %s",
+                                      ren1_src, ren1_dst, branch1,
+                                      ren2->pair->one->path, ren2->pair->two->path, branch2);
+                               conflict_rename_rename_2(ren1, branch1, ren2, branch2);
+                       } else
+                               try_merge = 1;
+                       if (try_merge) {
+                               struct diff_filespec *o, *a, *b;
+                               struct merge_file_info mfi;
+                               src_other.path = (char *)ren1_src;
+                               o = ren1->pair->one;
+                               if (a_renames == renames1) {
+                                       a = ren1->pair->two;
+                                       b = &src_other;
+                               } else {
+                                       b = ren1->pair->two;
+                                       a = &src_other;
+                               }
+                               mfi = merge_file(o, a, b,
+                                               a_branch, b_branch);
+                               if (mfi.clean &&
+                                   sha_eq(mfi.sha, ren1->pair->two->sha1) &&
+                                   mfi.mode == ren1->pair->two->mode)
+                                       /*
+                                        * This messaged is part of
+                                        * t6022 test. If you change
+                                        * it update the test too.
+                                        */
+                                       output(3, "Skipped %s (merged same as existing)", ren1_dst);
+                               else {
+                                       if (mfi.merge || !mfi.clean)
+                                               output(1, "Renamed %s => %s", ren1_src, ren1_dst);
+                                       if (mfi.merge)
+                                               output(2, "Auto-merged %s", ren1_dst);
+                                       if (!mfi.clean) {
+                                               output(1, "CONFLICT (rename/modify): Merge conflict in %s",
+                                                      ren1_dst);
+                                               clean_merge = 0;
+                                               if (!index_only)
+                                                       update_stages(ren1_dst,
+                                                                     o, a, b, 1);
+                                       }
+                                       update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
+                               }
+                       }
+               }
+       }
+       path_list_clear(&a_by_dst, 0);
+       path_list_clear(&b_by_dst, 0);
+       return clean_merge;
+ }
+ static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
+ {
+       return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
+ }
+ /* Per entry merge function */
+ static int process_entry(const char *path, struct stage_data *entry,
+                        const char *branch1,
+                        const char *branch2)
+ {
+       /*
+       printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
+       print_index_entry("\tpath: ", entry);
+       */
+       int clean_merge = 1;
+       unsigned o_mode = entry->stages[1].mode;
+       unsigned a_mode = entry->stages[2].mode;
+       unsigned b_mode = entry->stages[3].mode;
+       unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
+       unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
+       unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
+       if (o_sha && (!a_sha || !b_sha)) {
+               /* Case A: Deleted in one */
+               if ((!a_sha && !b_sha) ||
+                   (sha_eq(a_sha, o_sha) && !b_sha) ||
+                   (!a_sha && sha_eq(b_sha, o_sha))) {
+                       /* Deleted in both or deleted in one and
+                        * unchanged in the other */
+                       if (a_sha)
+                               output(2, "Removed %s", path);
+                       /* do not touch working file if it did not exist */
+                       remove_file(1, path, !a_sha);
+               } else {
+                       /* Deleted in one and changed in the other */
+                       clean_merge = 0;
+                       if (!a_sha) {
+                               output(1, "CONFLICT (delete/modify): %s deleted in %s "
+                                      "and modified in %s. Version %s of %s left in tree.",
+                                      path, branch1,
+                                      branch2, branch2, path);
+                               update_file(0, b_sha, b_mode, path);
+                       } else {
+                               output(1, "CONFLICT (delete/modify): %s deleted in %s "
+                                      "and modified in %s. Version %s of %s left in tree.",
+                                      path, branch2,
+                                      branch1, branch1, path);
+                               update_file(0, a_sha, a_mode, path);
+                       }
+               }
+       } else if ((!o_sha && a_sha && !b_sha) ||
+                  (!o_sha && !a_sha && b_sha)) {
+               /* Case B: Added in one. */
+               const char *add_branch;
+               const char *other_branch;
+               unsigned mode;
+               const unsigned char *sha;
+               const char *conf;
+               if (a_sha) {
+                       add_branch = branch1;
+                       other_branch = branch2;
+                       mode = a_mode;
+                       sha = a_sha;
+                       conf = "file/directory";
+               } else {
+                       add_branch = branch2;
+                       other_branch = branch1;
+                       mode = b_mode;
+                       sha = b_sha;
+                       conf = "directory/file";
+               }
+               if (path_list_has_path(&current_directory_set, path)) {
+                       const char *new_path = unique_path(path, add_branch);
+                       clean_merge = 0;
+                       output(1, "CONFLICT (%s): There is a directory with name %s in %s. "
+                              "Added %s as %s",
+                              conf, path, other_branch, path, new_path);
+                       remove_file(0, path, 0);
+                       update_file(0, sha, mode, new_path);
+               } else {
+                       output(2, "Added %s", path);
+                       update_file(1, sha, mode, path);
+               }
+       } else if (a_sha && b_sha) {
+               /* Case C: Added in both (check for same permissions) and */
+               /* case D: Modified in both, but differently. */
+               const char *reason = "content";
+               struct merge_file_info mfi;
+               struct diff_filespec o, a, b;
+               if (!o_sha) {
+                       reason = "add/add";
+                       o_sha = (unsigned char *)null_sha1;
+               }
+               output(2, "Auto-merged %s", path);
+               o.path = a.path = b.path = (char *)path;
+               hashcpy(o.sha1, o_sha);
+               o.mode = o_mode;
+               hashcpy(a.sha1, a_sha);
+               a.mode = a_mode;
+               hashcpy(b.sha1, b_sha);
+               b.mode = b_mode;
+               mfi = merge_file(&o, &a, &b,
+                                branch1, branch2);
+               clean_merge = mfi.clean;
+               if (mfi.clean)
+                       update_file(1, mfi.sha, mfi.mode, path);
+               else if (S_ISGITLINK(mfi.mode))
+                       output(1, "CONFLICT (submodule): Merge conflict in %s "
+                              "- needs %s", path, sha1_to_hex(b.sha1));
+               else {
+                       output(1, "CONFLICT (%s): Merge conflict in %s",
+                                       reason, path);
+                       if (index_only)
+                               update_file(0, mfi.sha, mfi.mode, path);
+                       else
+                               update_file_flags(mfi.sha, mfi.mode, path,
+                                             0 /* update_cache */, 1 /* update_working_directory */);
+               }
+       } else if (!o_sha && !a_sha && !b_sha) {
+               /*
+                * this entry was deleted altogether. a_mode == 0 means
+                * we had that path and want to actively remove it.
+                */
+               remove_file(1, path, !a_mode);
+       } else
+               die("Fatal merge failure, shouldn't happen.");
+       return clean_merge;
+ }
+ int merge_trees(struct tree *head,
+               struct tree *merge,
+               struct tree *common,
+               const char *branch1,
+               const char *branch2,
+               struct tree **result)
+ {
+       int code, clean;
+       if (subtree_merge) {
+               merge = shift_tree_object(head, merge);
+               common = shift_tree_object(head, common);
+       }
+       if (sha_eq(common->object.sha1, merge->object.sha1)) {
+               output(0, "Already uptodate!");
+               *result = head;
+               return 1;
+       }
+       code = git_merge_trees(index_only, common, head, merge);
+       if (code != 0)
+               die("merging of trees %s and %s failed",
+                   sha1_to_hex(head->object.sha1),
+                   sha1_to_hex(merge->object.sha1));
+       if (unmerged_cache()) {
+               struct path_list *entries, *re_head, *re_merge;
+               int i;
+               path_list_clear(&current_file_set, 1);
+               path_list_clear(&current_directory_set, 1);
+               get_files_dirs(head);
+               get_files_dirs(merge);
+               entries = get_unmerged();
+               re_head  = get_renames(head, common, head, merge, entries);
+               re_merge = get_renames(merge, common, head, merge, entries);
+               clean = process_renames(re_head, re_merge,
+                               branch1, branch2);
+               for (i = 0; i < entries->nr; i++) {
+                       const char *path = entries->items[i].path;
+                       struct stage_data *e = entries->items[i].util;
+                       if (!e->processed
+                               && !process_entry(path, e, branch1, branch2))
+                               clean = 0;
+               }
+               path_list_clear(re_merge, 0);
+               path_list_clear(re_head, 0);
+               path_list_clear(entries, 1);
+       }
+       else
+               clean = 1;
+       if (index_only)
+               *result = write_tree_from_memory();
+       return clean;
+ }
+ static struct commit_list *reverse_commit_list(struct commit_list *list)
+ {
+       struct commit_list *next = NULL, *current, *backup;
+       for (current = list; current; current = backup) {
+               backup = current->next;
+               current->next = next;
+               next = current;
+       }
+       return next;
+ }
+ /*
+  * Merge the commits h1 and h2, return the resulting virtual
+  * commit object and a flag indicating the cleanness of the merge.
+  */
+ int merge_recursive(struct commit *h1,
+                   struct commit *h2,
+                   const char *branch1,
+                   const char *branch2,
+                   struct commit_list *ca,
+                   struct commit **result)
+ {
+       struct commit_list *iter;
+       struct commit *merged_common_ancestors;
+       struct tree *mrtree = mrtree;
+       int clean;
+       if (show(4)) {
+               output(4, "Merging:");
+               output_commit_title(h1);
+               output_commit_title(h2);
+       }
+       if (!ca) {
+               ca = get_merge_bases(h1, h2, 1);
+               ca = reverse_commit_list(ca);
+       }
+       if (show(5)) {
+               output(5, "found %u common ancestor(s):", commit_list_count(ca));
+               for (iter = ca; iter; iter = iter->next)
+                       output_commit_title(iter->item);
+       }
+       merged_common_ancestors = pop_commit(&ca);
+       if (merged_common_ancestors == NULL) {
+               /* if there is no common ancestor, make an empty tree */
+               struct tree *tree = xcalloc(1, sizeof(struct tree));
+               tree->object.parsed = 1;
+               tree->object.type = OBJ_TREE;
+               pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
+               merged_common_ancestors = make_virtual_commit(tree, "ancestor");
+       }
+       for (iter = ca; iter; iter = iter->next) {
+               call_depth++;
+               /*
+                * When the merge fails, the result contains files
+                * with conflict markers. The cleanness flag is
+                * ignored, it was never actually used, as result of
+                * merge_trees has always overwritten it: the committed
+                * "conflicts" were already resolved.
+                */
+               discard_cache();
+               merge_recursive(merged_common_ancestors, iter->item,
+                               "Temporary merge branch 1",
+                               "Temporary merge branch 2",
+                               NULL,
+                               &merged_common_ancestors);
+               call_depth--;
+               if (!merged_common_ancestors)
+                       die("merge returned no commit");
+       }
+       discard_cache();
+       if (!call_depth) {
+               read_cache();
+               index_only = 0;
+       } else
+               index_only = 1;
+       clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
+                           branch1, branch2, &mrtree);
+       if (index_only) {
+               *result = make_virtual_commit(mrtree, "merged tree");
+               commit_list_insert(h1, &(*result)->parents);
+               commit_list_insert(h2, &(*result)->parents->next);
+       }
+       flush_output();
+       return clean;
+ }
+ static const char *better_branch_name(const char *branch)
+ {
+       static char githead_env[8 + 40 + 1];
+       char *name;
+       if (strlen(branch) != 40)
+               return branch;
+       sprintf(githead_env, "GITHEAD_%s", branch);
+       name = getenv(githead_env);
+       return name ? name : branch;
+ }
+ static struct commit *get_ref(const char *ref)
+ {
+       unsigned char sha1[20];
+       struct object *object;
+       if (get_sha1(ref, sha1))
+               die("Could not resolve ref '%s'", ref);
+       object = deref_tag(parse_object(sha1), ref, strlen(ref));
++      if (!object)
++              return NULL;
+       if (object->type == OBJ_TREE)
+               return make_virtual_commit((struct tree*)object,
+                       better_branch_name(ref));
+       if (object->type != OBJ_COMMIT)
+               return NULL;
+       if (parse_commit((struct commit *)object))
+               die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
+       return (struct commit *)object;
+ }
+ static int merge_config(const char *var, const char *value)
+ {
+       if (!strcasecmp(var, "merge.verbosity")) {
+               verbosity = git_config_int(var, value);
+               return 0;
+       }
+       if (!strcasecmp(var, "diff.renamelimit")) {
+               rename_limit = git_config_int(var, value);
+               return 0;
+       }
+       return git_default_config(var, value);
+ }
+ int cmd_merge_recursive(int argc, const char **argv, const char *prefix)
+ {
+       static const char *bases[20];
+       static unsigned bases_count = 0;
+       int i, clean;
+       const char *branch1, *branch2;
+       struct commit *result, *h1, *h2;
+       struct commit_list *ca = NULL;
+       struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
+       int index_fd;
+       if (argv[0]) {
+               int namelen = strlen(argv[0]);
+               if (8 < namelen &&
+                   !strcmp(argv[0] + namelen - 8, "-subtree"))
+                       subtree_merge = 1;
+       }
+       git_config(merge_config);
+       if (getenv("GIT_MERGE_VERBOSITY"))
+               verbosity = strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
+       if (argc < 4)
+               die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
+       for (i = 1; i < argc; ++i) {
+               if (!strcmp(argv[i], "--"))
+                       break;
+               if (bases_count < sizeof(bases)/sizeof(*bases))
+                       bases[bases_count++] = argv[i];
+       }
+       if (argc - i != 3) /* "--" "<head>" "<remote>" */
+               die("Not handling anything other than two heads merge.");
+       if (verbosity >= 5)
+               buffer_output = 0;
+       branch1 = argv[++i];
+       branch2 = argv[++i];
+       h1 = get_ref(branch1);
+       h2 = get_ref(branch2);
+       branch1 = better_branch_name(branch1);
+       branch2 = better_branch_name(branch2);
+       if (show(3))
+               printf("Merging %s with %s\n", branch1, branch2);
+       index_fd = hold_locked_index(lock, 1);
+       for (i = 0; i < bases_count; i++) {
+               struct commit *ancestor = get_ref(bases[i]);
+               ca = commit_list_insert(ancestor, &ca);
+       }
+       clean = merge_recursive(h1, h2, branch1, branch2, ca, &result);
+       if (active_cache_changed &&
+           (write_cache(index_fd, active_cache, active_nr) ||
+            commit_locked_index(lock)))
+                       die ("unable to write %s", get_index_file());
+       return clean ? 0: 1;
+ }
diff --combined builtin-read-tree.c
index 7bdc312e3861103fa83b20b939962a8bc8e6cc0a,1d9d125b91f976ebbc5ef0b1ca0fe7c0caeabb8a..0138f5a9172034b2ce34222ff077a975f8998005
@@@ -41,12 -41,11 +41,12 @@@ static int read_cache_unmerged(void
        for (i = 0; i < active_nr; i++) {
                struct cache_entry *ce = active_cache[i];
                if (ce_stage(ce)) {
 +                      remove_index_entry(ce);
                        if (last && !strcmp(ce->name, last->name))
                                continue;
                        cache_tree_invalidate_path(active_cache_tree, ce->name);
                        last = ce;
 -                      ce->ce_flags |= CE_REMOVE;
 +                      continue;
                }
                *dst++ = ce;
        }
@@@ -269,7 -268,8 +269,8 @@@ int cmd_read_tree(int argc, const char 
                parse_tree(tree);
                init_tree_desc(t+i, tree->buffer, tree->size);
        }
-       unpack_trees(nr_trees, t, &opts);
+       if (unpack_trees(nr_trees, t, &opts))
+               return 128;
  
        /*
         * When reading only one tree (either the most basic form,
diff --combined builtin.h
index 3d1628c597b21cc22b750809c27d4499e725d259,25d91bbfb21ea3c1ea067b10f7ea033d3563936a..674c8a141faf808883c9de283d10da01b3f9c2d5
+++ b/builtin.h
@@@ -8,6 -8,7 +8,6 @@@ extern const char git_usage_string[]
  
  extern void list_common_cmds_help(void);
  extern void help_unknown_cmd(const char *cmd);
 -extern int write_tree(unsigned char *sha1, int missing_ok, const char *prefix);
  extern void prune_packed_objects(int);
  
  extern int cmd_add(int argc, const char **argv, const char *prefix);
@@@ -18,6 -19,7 +18,7 @@@ extern int cmd_blame(int argc, const ch
  extern int cmd_branch(int argc, const char **argv, const char *prefix);
  extern int cmd_bundle(int argc, const char **argv, const char *prefix);
  extern int cmd_cat_file(int argc, const char **argv, const char *prefix);
+ extern int cmd_checkout(int argc, const char **argv, const char *prefix);
  extern int cmd_checkout_index(int argc, const char **argv, const char *prefix);
  extern int cmd_check_attr(int argc, const char **argv, const char *prefix);
  extern int cmd_check_ref_format(int argc, const char **argv, const char *prefix);
@@@ -56,6 -58,7 +57,7 @@@ extern int cmd_mailsplit(int argc, cons
  extern int cmd_merge_base(int argc, const char **argv, const char *prefix);
  extern int cmd_merge_ours(int argc, const char **argv, const char *prefix);
  extern int cmd_merge_file(int argc, const char **argv, const char *prefix);
+ extern int cmd_merge_recursive(int argc, const char **argv, const char *prefix);
  extern int cmd_mv(int argc, const char **argv, const char *prefix);
  extern int cmd_name_rev(int argc, const char **argv, const char *prefix);
  extern int cmd_pack_objects(int argc, const char **argv, const char *prefix);
diff --combined cache.h
index 7769f055e964e4c1e29a1129050dd439940e29f0,888895a9695f9362df8c0ac03f3e762fd61d2a55..9ebe7913b01aed7cbfa089ce811e57bbc64a6e15
+++ b/cache.h
@@@ -110,6 -110,7 +110,6 @@@ struct ondisk_cache_entry 
  };
  
  struct cache_entry {
 -      struct cache_entry *next;
        unsigned int ce_ctime;
        unsigned int ce_mtime;
        unsigned int ce_dev;
        unsigned int ce_size;
        unsigned int ce_flags;
        unsigned char sha1[20];
 +      struct cache_entry *next;
        char name[FLEX_ARRAY]; /* more */
  };
  
  #define CE_UPDATE    (0x10000)
  #define CE_REMOVE    (0x20000)
  #define CE_UPTODATE  (0x40000)
 -#define CE_UNHASHED  (0x80000)
 +
 +#define CE_HASHED    (0x100000)
 +#define CE_UNHASHED  (0x200000)
 +
 +/*
 + * Copy the sha1 and stat state of a cache entry from one to
 + * another. But we never change the name, or the hash state!
 + */
 +#define CE_STATE_MASK (CE_HASHED | CE_UNHASHED)
 +static inline void copy_cache_entry(struct cache_entry *dst, struct cache_entry *src)
 +{
 +      unsigned int state = dst->ce_flags & CE_STATE_MASK;
 +
 +      /* Don't copy hash chain and name */
 +      memcpy(dst, src, offsetof(struct cache_entry, next));
 +
 +      /* Restore the hash state */
 +      dst->ce_flags = (dst->ce_flags & ~CE_STATE_MASK) | state;
 +}
 +
 +/*
 + * We don't actually *remove* it, we can just mark it invalid so that
 + * we won't find it in lookups.
 + *
 + * Not only would we have to search the lists (simple enough), but
 + * we'd also have to rehash other hash buckets in case this makes the
 + * hash bucket empty (common). So it's much better to just mark
 + * it.
 + */
 +static inline void remove_index_entry(struct cache_entry *ce)
 +{
 +      ce->ce_flags |= CE_UNHASHED;
 +}
  
  static inline unsigned create_ce_flags(size_t len, unsigned stage)
  {
@@@ -210,18 -178,6 +210,18 @@@ static inline unsigned int ce_mode_from
        }
        return create_ce_mode(mode);
  }
 +static inline int ce_to_dtype(const struct cache_entry *ce)
 +{
 +      unsigned ce_mode = ntohl(ce->ce_mode);
 +      if (S_ISREG(ce_mode))
 +              return DT_REG;
 +      else if (S_ISDIR(ce_mode) || S_ISGITLINK(ce_mode))
 +              return DT_DIR;
 +      else if (S_ISLNK(ce_mode))
 +              return DT_LNK;
 +      else
 +              return DT_UNKNOWN;
 +}
  #define canon_mode(mode) \
        (S_ISREG(mode) ? (S_IFREG | ce_permissions(mode)) : \
        S_ISLNK(mode) ? S_IFLNK : S_ISDIR(mode) ? S_IFDIR : S_IFGITLINK)
@@@ -252,6 -208,7 +252,7 @@@ extern struct index_state the_index
  #define read_cache_from(path) read_index_from(&the_index, (path))
  #define write_cache(newfd, cache, entries) write_index(&the_index, (newfd))
  #define discard_cache() discard_index(&the_index)
+ #define unmerged_cache() unmerged_index(&the_index)
  #define cache_name_pos(name, namelen) index_name_pos(&the_index,(name),(namelen))
  #define add_cache_entry(ce, option) add_index_entry(&the_index, (ce), (option))
  #define remove_cache_entry_at(pos) remove_index_entry_at(&the_index, (pos))
@@@ -346,6 -303,7 +347,7 @@@ extern int read_index(struct index_stat
  extern int read_index_from(struct index_state *, const char *path);
  extern int write_index(struct index_state *, int newfd);
  extern int discard_index(struct index_state *);
+ extern int unmerged_index(struct index_state *);
  extern int verify_path(const char *path);
  extern int index_name_exists(struct index_state *istate, const char *name, int namelen);
  extern int index_name_pos(struct index_state *, const char *name, int namelen);
@@@ -415,14 -373,6 +417,14 @@@ extern size_t packed_git_limit
  extern size_t delta_base_cache_limit;
  extern int auto_crlf;
  
 +enum safe_crlf {
 +      SAFE_CRLF_FALSE = 0,
 +      SAFE_CRLF_FAIL = 1,
 +      SAFE_CRLF_WARN = 2,
 +};
 +
 +extern enum safe_crlf safe_crlf;
 +
  #define GIT_REPO_VERSION 0
  extern int repository_format_version;
  extern int check_repository_format(void);
@@@ -677,16 -627,11 +679,16 @@@ extern int git_parse_ulong(const char *
  extern int git_config_int(const char *, const char *);
  extern unsigned long git_config_ulong(const char *, const char *);
  extern int git_config_bool(const char *, const char *);
 +extern int git_config_string(const char **, const char *, const char *);
  extern int git_config_set(const char *, const char *);
  extern int git_config_set_multivar(const char *, const char *, const char *, int);
  extern int git_config_rename_section(const char *, const char *);
  extern const char *git_etc_gitconfig(void);
  extern int check_repository_format_version(const char *var, const char *value);
 +extern int git_env_bool(const char *, int);
 +extern int git_config_system(void);
 +extern int git_config_global(void);
 +extern int config_error_nonbool(const char *);
  
  #define MAX_GITNAME (1000)
  extern char git_default_email[MAX_GITNAME];
@@@ -698,7 -643,6 +700,7 @@@ extern const char *git_log_output_encod
  /* IO helper functions */
  extern void maybe_flush_or_die(FILE *, const char *);
  extern int copy_fd(int ifd, int ofd);
 +extern int copy_file(const char *dst, const char *src, int mode);
  extern int read_in_full(int fd, void *buf, size_t count);
  extern int write_in_full(int fd, const void *buf, size_t count);
  extern void write_or_die(int fd, const void *buf, size_t count);
@@@ -707,12 -651,12 +709,12 @@@ extern int write_or_whine_pipe(int fd, 
  
  /* pager.c */
  extern void setup_pager(void);
 -extern char *pager_program;
 +extern const char *pager_program;
  extern int pager_in_use(void);
  extern int pager_use_color;
  
 -extern char *editor_program;
 -extern char *excludes_file;
 +extern const char *editor_program;
 +extern const char *excludes_file;
  
  /* base85 */
  int decode_85(char *dst, const char *line, int linelen);
@@@ -732,8 -676,7 +734,8 @@@ extern void trace_argv_printf(const cha
  
  /* convert.c */
  /* returns 1 if *dst was used */
 -extern int convert_to_git(const char *path, const char *src, size_t len, struct strbuf *dst);
 +extern int convert_to_git(const char *path, const char *src, size_t len,
 +                          struct strbuf *dst, enum safe_crlf checksafe);
  extern int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst);
  
  /* add */
@@@ -752,7 -695,6 +754,7 @@@ void shift_tree(const unsigned char *, 
  #define WS_TRAILING_SPACE     01
  #define WS_SPACE_BEFORE_TAB   02
  #define WS_INDENT_WITH_NON_TAB        04
 +#define WS_CR_AT_EOL           010
  #define WS_DEFAULT_RULE (WS_TRAILING_SPACE|WS_SPACE_BEFORE_TAB)
  extern unsigned whitespace_rule_cfg;
  extern unsigned whitespace_rule(const char *);
@@@ -761,13 -703,10 +763,13 @@@ extern unsigned check_and_emit_line(con
      FILE *stream, const char *set,
      const char *reset, const char *ws);
  extern char *whitespace_error_string(unsigned ws);
 +extern int ws_fix_copy(char *, const char *, int, unsigned, int *);
  
  /* ls-files */
  int pathspec_match(const char **spec, char *matched, const char *filename, int skiplen);
  int report_path_error(const char *ps_matched, const char **pathspec, int prefix_offset);
  void overlay_tree_on_cache(const char *tree_name, const char *prefix);
  
 +char *alias_lookup(const char *alias);
 +
  #endif /* CACHE_H */
index 0000000000000000000000000000000000000000,5621c69d86062c7c75c0b8c2749d34efc78cafb4..1a7689a48f07a6ed2bb156f745bfea19a10e3eb9
mode 000000,100755..100755
--- /dev/null
@@@ -1,0 -1,298 +1,302 @@@
 -if rev=$(git rev-parse --verify "$arg^0" 2>/dev/null)
+ #!/bin/sh
+ OPTIONS_KEEPDASHDASH=t
+ OPTIONS_SPEC="\
+ git-checkout [options] [<branch>] [<paths>...]
+ --
+ b=          create a new branch started at <branch>
+ l           create the new branch's reflog
+ track       arrange that the new branch tracks the remote branch
+ f           proceed even if the index or working tree is not HEAD
+ m           merge local modifications into the new branch
+ q,quiet     be quiet
+ "
+ SUBDIRECTORY_OK=Sometimes
+ . git-sh-setup
+ require_work_tree
+ old_name=HEAD
+ old=$(git rev-parse --verify $old_name 2>/dev/null)
+ oldbranch=$(git symbolic-ref $old_name 2>/dev/null)
+ new=
+ new_name=
+ force=
+ branch=
+ track=
+ newbranch=
+ newbranch_log=
+ merge=
+ quiet=
+ v=-v
+ LF='
+ '
+ while test $# != 0; do
+       case "$1" in
+       -b)
+               shift
+               newbranch="$1"
+               [ -z "$newbranch" ] &&
+                       die "git checkout: -b needs a branch name"
+               git show-ref --verify --quiet -- "refs/heads/$newbranch" &&
+                       die "git checkout: branch $newbranch already exists"
+               git check-ref-format "heads/$newbranch" ||
+                       die "git checkout: we do not like '$newbranch' as a branch name."
+               ;;
+       -l)
+               newbranch_log=-l
+               ;;
+       --track|--no-track)
+               track="$1"
+               ;;
+       -f)
+               force=1
+               ;;
+       -m)
+               merge=1
+               ;;
+       -q|--quiet)
+               quiet=1
+               v=
+               ;;
+       --)
+               shift
+               break
+               ;;
+       *)
+               usage
+               ;;
+       esac
+       shift
+ done
+ arg="$1"
 -elif rev=$(git rev-parse --verify "$arg^{tree}" 2>/dev/null)
++rev=$(git rev-parse --verify "$arg" 2>/dev/null)
++if rev=$(git rev-parse --verify "$rev^0" 2>/dev/null)
+ then
+       [ -z "$rev" ] && die "unknown flag $arg"
+       new_name="$arg"
+       if git show-ref --verify --quiet -- "refs/heads/$arg"
+       then
+               rev=$(git rev-parse --verify "refs/heads/$arg^0")
+               branch="$arg"
+       fi
+       new="$rev"
+       shift
 -      new_name="$arg^{tree}"
++elif rev=$(git rev-parse --verify "$rev^{tree}" 2>/dev/null)
+ then
+       # checking out selected paths from a tree-ish.
+       new="$rev"
 -    merge_error=$(git read-tree -m -u --exclude-per-directory=.gitignore $old $new 2>&1) || (
 -      case "$merge" in
 -      '')
 -              echo >&2 "$merge_error"
++      new_name="$rev^{tree}"
+       shift
+ fi
+ [ "$1" = "--" ] && shift
+ case "$newbranch,$track" in
+ ,--*)
+       die "git checkout: --track and --no-track require -b"
+ esac
+ case "$force$merge" in
+ 11)
+       die "git checkout: -f and -m are incompatible"
+ esac
+ # The behaviour of the command with and without explicit path
+ # parameters is quite different.
+ #
+ # Without paths, we are checking out everything in the work tree,
+ # possibly switching branches.  This is the traditional behaviour.
+ #
+ # With paths, we are _never_ switching branch, but checking out
+ # the named paths from either index (when no rev is given),
+ # or the named tree-ish (when rev is given).
+ if test "$#" -ge 1
+ then
+       hint=
+       if test "$#" -eq 1
+       then
+               hint="
+ Did you intend to checkout '$@' which can not be resolved as commit?"
+       fi
+       if test '' != "$newbranch$force$merge"
+       then
+               die "git checkout: updating paths is incompatible with switching branches/forcing$hint"
+       fi
+       if test '' != "$new"
+       then
+               # from a specific tree-ish; note that this is for
+               # rescuing paths and is never meant to remove what
+               # is not in the named tree-ish.
+               git ls-tree --full-name -r "$new" "$@" |
+               git update-index --index-info || exit $?
+       fi
+       # Make sure the request is about existing paths.
+       git ls-files --full-name --error-unmatch -- "$@" >/dev/null || exit
+       git ls-files --full-name -- "$@" |
+               (cd_to_toplevel && git checkout-index -f -u --stdin)
+       # Run a post-checkout hook -- the HEAD does not change so the
+       # current HEAD is passed in for both args
+       if test -x "$GIT_DIR"/hooks/post-checkout; then
+           "$GIT_DIR"/hooks/post-checkout $old $old 0
+       fi
+       exit $?
+ else
+       # Make sure we did not fall back on $arg^{tree} codepath
+       # since we are not checking out from an arbitrary tree-ish,
+       # but switching branches.
+       if test '' != "$new"
+       then
+               git rev-parse --verify "$new^{commit}" >/dev/null 2>&1 ||
+               die "Cannot switch branch to a non-commit."
+       fi
+ fi
+ # We are switching branches and checking out trees, so
+ # we *NEED* to be at the toplevel.
+ cd_to_toplevel
+ [ -z "$new" ] && new=$old && new_name="$old_name"
+ # If we don't have an existing branch that we're switching to,
+ # and we don't have a new branch name for the target we
+ # are switching to, then we are detaching our HEAD from any
+ # branch.  However, if "git checkout HEAD" detaches the HEAD
+ # from the current branch, even though that may be logically
+ # correct, it feels somewhat funny.  More importantly, we do not
+ # want "git checkout" nor "git checkout -f" to detach HEAD.
+ detached=
+ detach_warn=
+ describe_detached_head () {
+       test -n "$quiet" || {
+               printf >&2 "$1 "
+               GIT_PAGER= git log >&2 -1 --pretty=oneline --abbrev-commit "$2" --
+       }
+ }
+ if test -z "$branch$newbranch" && test "$new_name" != "$old_name"
+ then
+       detached="$new"
+       if test -n "$oldbranch" && test -z "$quiet"
+       then
+               detach_warn="Note: moving to \"$new_name\" which isn't a local branch
+ If you want to create a new branch from this checkout, you may do so
+ (now or later) by using -b with the checkout command again. Example:
+   git checkout -b <new_branch_name>"
+       fi
+ elif test -z "$oldbranch" && test "$new" != "$old"
+ then
+       describe_detached_head 'Previous HEAD position was' "$old"
+ fi
+ if [ "X$old" = X ]
+ then
+       if test -z "$quiet"
+       then
+               echo >&2 "warning: You appear to be on a branch yet to be born."
+               echo >&2 "warning: Forcing checkout of $new_name."
+       fi
+       force=1
+ fi
+ if [ "$force" ]
+ then
+     git read-tree $v --reset -u $new
+ else
+     git update-index --refresh >/dev/null
++    git read-tree $v -m -u --exclude-per-directory=.gitignore $old $new || (
++      case "$merge,$v" in
++      ,*)
+               exit 1 ;;
++      1,)
++              ;; # quiet
++      *)
++              echo >&2 "Falling back to 3-way merge..." ;;
+       esac
+       # Match the index to the working tree, and do a three-way.
+       git diff-files --name-only | git update-index --remove --stdin &&
+       work=`git write-tree` &&
+       git read-tree $v --reset -u $new || exit
+       eval GITHEAD_$new='${new_name:-${branch:-$new}}' &&
+       eval GITHEAD_$work=local &&
+       export GITHEAD_$new GITHEAD_$work &&
+       git merge-recursive $old -- $new $work
+       # Do not register the cleanly merged paths in the index yet.
+       # this is not a real merge before committing, but just carrying
+       # the working tree changes along.
+       unmerged=`git ls-files -u`
+       git read-tree $v --reset $new
+       case "$unmerged" in
+       '')     ;;
+       *)
+               (
+                       z40=0000000000000000000000000000000000000000
+                       echo "$unmerged" |
+                       sed -e 's/^[0-7]* [0-9a-f]* /'"0 $z40 /"
+                       echo "$unmerged"
+               ) | git update-index --index-info
+               ;;
+       esac
+       exit 0
+     )
+     saved_err=$?
+     if test "$saved_err" = 0 && test -z "$quiet"
+     then
+       git diff-index --name-status "$new"
+     fi
+     (exit $saved_err)
+ fi
+ #
+ # Switch the HEAD pointer to the new branch if we
+ # checked out a branch head, and remove any potential
+ # old MERGE_HEAD's (subsequent commits will clearly not
+ # be based on them, since we re-set the index)
+ #
+ if [ "$?" -eq 0 ]; then
+       if [ "$newbranch" ]; then
+               git branch $track $newbranch_log "$newbranch" "$new_name" || exit
+               branch="$newbranch"
+       fi
+       if test -n "$branch"
+       then
+               old_branch_name=`expr "z$oldbranch" : 'zrefs/heads/\(.*\)'`
+               GIT_DIR="$GIT_DIR" git symbolic-ref -m "checkout: moving from ${old_branch_name:-$old} to $branch" HEAD "refs/heads/$branch"
+               if test -n "$quiet"
+               then
+                       true    # nothing
+               elif test "refs/heads/$branch" = "$oldbranch"
+               then
+                       echo >&2 "Already on branch \"$branch\""
+               else
+                       echo >&2 "Switched to${newbranch:+ a new} branch \"$branch\""
+               fi
+       elif test -n "$detached"
+       then
+               old_branch_name=`expr "z$oldbranch" : 'zrefs/heads/\(.*\)'`
+               git update-ref --no-deref -m "checkout: moving from ${old_branch_name:-$old} to $arg" HEAD "$detached" ||
+                       die "Cannot detach HEAD"
+               if test -n "$detach_warn"
+               then
+                       echo >&2 "$detach_warn"
+               fi
+               describe_detached_head 'HEAD is now at' HEAD
+       fi
+       rm -f "$GIT_DIR/MERGE_HEAD"
+ else
+       exit 1
+ fi
+ # Run a post-checkout hook
+ if test -x "$GIT_DIR"/hooks/post-checkout; then
+       "$GIT_DIR"/hooks/post-checkout $old $new 1
+ fi
diff --combined git.c
index 8f08b12295e1641577ffd61ee71c7b7247645f81,bd424ea9bd9e54a214f587acfc2ca266105d0168..9cca81a60e6d4f93cf3132b76fd8f147a6a5d98f
--- 1/git.c
--- 2/git.c
+++ b/git.c
@@@ -87,6 -87,17 +87,6 @@@ static int handle_options(const char**
        return handled;
  }
  
 -static const char *alias_command;
 -static char *alias_string;
 -
 -static int git_alias_config(const char *var, const char *value)
 -{
 -      if (!prefixcmp(var, "alias.") && !strcmp(var + 6, alias_command)) {
 -              alias_string = xstrdup(value);
 -      }
 -      return 0;
 -}
 -
  static int split_cmdline(char *cmdline, const char ***argv)
  {
        int src, dst, count = 0, size = 16;
@@@ -146,13 -157,11 +146,13 @@@ static int handle_alias(int *argcp, con
        const char *subdir;
        int count, option_count;
        const char** new_argv;
 +      const char *alias_command;
 +      char *alias_string;
  
        subdir = setup_git_directory_gently(&nongit);
  
        alias_command = (*argv)[0];
 -      git_config(git_alias_config);
 +      alias_string = alias_lookup(alias_command);
        if (alias_string) {
                if (alias_string[0] == '!') {
                        if (*argcp > 1) {
@@@ -278,6 -287,7 +278,7 @@@ static void handle_internal_command(in
                { "branch", cmd_branch, RUN_SETUP },
                { "bundle", cmd_bundle },
                { "cat-file", cmd_cat_file, RUN_SETUP },
+               { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
                { "checkout-index", cmd_checkout_index,
                        RUN_SETUP | NEED_WORK_TREE},
                { "check-ref-format", cmd_check_ref_format },
                { "merge-base", cmd_merge_base, RUN_SETUP },
                { "merge-file", cmd_merge_file },
                { "merge-ours", cmd_merge_ours, RUN_SETUP },
+               { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
+               { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
                { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
                { "name-rev", cmd_name_rev, RUN_SETUP },
                { "pack-objects", cmd_pack_objects, RUN_SETUP },
diff --combined read-cache.c
index fee0c80734db2d5106c4c6fd6bc396af1831c392,22d7b462454463fb149d02ac62415fc63aca7672..657f0c5894c65831b80ceee54d161d0beac1d733
@@@ -37,13 -37,8 +37,13 @@@ static unsigned int hash_name(const cha
  static void hash_index_entry(struct index_state *istate, struct cache_entry *ce)
  {
        void **pos;
 -      unsigned int hash = hash_name(ce->name, ce_namelen(ce));
 +      unsigned int hash;
  
 +      if (ce->ce_flags & CE_HASHED)
 +              return;
 +      ce->ce_flags |= CE_HASHED;
 +      ce->next = NULL;
 +      hash = hash_name(ce->name, ce_namelen(ce));
        pos = insert_hash(hash, ce, &istate->name_hash);
        if (pos) {
                ce->next = *pos;
@@@ -64,18 -59,33 +64,18 @@@ static void lazy_init_name_hash(struct 
  
  static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
  {
 +      ce->ce_flags &= ~CE_UNHASHED;
        istate->cache[nr] = ce;
        if (istate->name_hash_initialized)
                hash_index_entry(istate, ce);
  }
  
 -/*
 - * We don't actually *remove* it, we can just mark it invalid so that
 - * we won't find it in lookups.
 - *
 - * Not only would we have to search the lists (simple enough), but
 - * we'd also have to rehash other hash buckets in case this makes the
 - * hash bucket empty (common). So it's much better to just mark
 - * it.
 - */
 -static void remove_hash_entry(struct index_state *istate, struct cache_entry *ce)
 -{
 -      ce->ce_flags |= CE_UNHASHED;
 -}
 -
  static void replace_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
  {
        struct cache_entry *old = istate->cache[nr];
  
 -      if (ce != old) {
 -              remove_hash_entry(istate, old);
 -              set_index_entry(istate, nr, ce);
 -      }
 +      remove_index_entry(old);
 +      set_index_entry(istate, nr, ce);
        istate->cache_changed = 1;
  }
  
@@@ -403,7 -413,7 +403,7 @@@ int remove_index_entry_at(struct index_
  {
        struct cache_entry *ce = istate->cache[pos];
  
 -      remove_hash_entry(istate, ce);
 +      remove_index_entry(ce);
        istate->cache_changed = 1;
        istate->cache_nr--;
        if (pos >= istate->cache_nr)
@@@ -1166,6 -1176,16 +1166,16 @@@ int discard_index(struct index_state *i
        return 0;
  }
  
+ int unmerged_index(struct index_state *istate)
+ {
+       int i;
+       for (i = 0; i < istate->cache_nr; i++) {
+               if (ce_stage(istate->cache[i]))
+                       return 1;
+       }
+       return 0;
+ }
  #define WRITE_BUFFER_SIZE 8192
  static unsigned char write_buffer[WRITE_BUFFER_SIZE];
  static unsigned long write_buffer_len;
diff --combined t/t7201-co.sh
index dbf1ace29ef8ad178a0ad8539e6bde30482ee60f,0fa94678ad223e7a6f9db21a26c32648483701bc..724adef0bfdc1f9028f112451c76d9053b60223f
@@@ -83,13 -83,13 +83,13 @@@ test_expect_success "checkout with unre
        fill 0 1 2 3 4 5 6 7 8 >same &&
        cp same kept
        git checkout side >messages &&
-       git diff same kept
+       diff -u same kept
        (cat > messages.expect <<EOF
  M     same
  EOF
  ) &&
        touch messages.expect &&
-       git diff messages.expect messages
+       diff -u messages.expect messages
  '
  
  test_expect_success "checkout -m with dirty tree" '
        test "$(git symbolic-ref HEAD)" = "refs/heads/side" &&
  
        (cat >expect.messages <<EOF
- Merging side with local
- Merging:
- ab76817 Side M one, D two, A three
- virtual local
- found 1 common ancestor(s):
- 7329388 Initial A one, A two
- Auto-merged one
  M     one
  EOF
  ) &&
-       git diff expect.messages messages &&
+       diff -u expect.messages messages &&
  
        fill "M one" "A three" "D       two" >expect.master &&
        git diff --name-status master >current.master &&
-       diff expect.master current.master &&
+       diff -u expect.master current.master &&
  
        fill "M one" >expect.side &&
        git diff --name-status side >current.side &&
-       diff expect.side current.side &&
+       diff -u expect.side current.side &&
  
        : >expect.index &&
        git diff --cached >current.index &&
-       diff expect.index current.index
+       diff -u expect.index current.index
  '
  
  test_expect_success "checkout -m with dirty tree, renamed" '
  
        git checkout -m renamer &&
        fill 1 3 4 5 7 8 >expect &&
-       diff expect uno &&
+       diff -u expect uno &&
        ! test -f one &&
        git diff --cached >current &&
        ! test -s current
@@@ -168,7 -161,7 +161,7 @@@ test_expect_success 'checkout -m with m
        git diff master:one :3:uno |
        sed -e "1,/^@@/d" -e "/^ /d" -e "s/^-/d/" -e "s/^+/a/" >current &&
        fill d2 aT d7 aS >expect &&
-       diff current expect &&
+       diff -u current expect &&
        git diff --cached two >current &&
        ! test -s current
  '
@@@ -185,7 -178,7 +178,7 @@@ If you want to create a new branch fro
  HEAD is now at 7329388... Initial A one, A two
  EOF
  ) &&
-       git diff messages.expect messages &&
+       diff -u messages.expect messages &&
        H=$(git rev-parse --verify HEAD) &&
        M=$(git show-ref -s --verify refs/heads/master) &&
        test "z$H" = "z$M" &&
@@@ -214,22 -207,6 +207,22 @@@ test_expect_success 'checkout to detac
        fi
  '
  
 +test_expect_success 'checkout to detach HEAD with :/message' '
 +
 +      git checkout -f master && git clean -f &&
 +      git checkout ":/Initial" &&
 +      H=$(git rev-parse --verify HEAD) &&
 +      M=$(git show-ref -s --verify refs/heads/master) &&
 +      test "z$H" = "z$M" &&
 +      if git symbolic-ref HEAD >/dev/null 2>&1
 +      then
 +              echo "OOPS, HEAD is still symbolic???"
 +              false
 +      else
 +              : happy
 +      fi
 +'
 +
  test_expect_success 'checkout to detach HEAD with HEAD^0' '
  
        git checkout -f master && git clean -f &&
@@@ -286,4 -263,38 +279,38 @@@ test_expect_success 'checkout with ambi
  
  '
  
+ test_expect_success 'switch branches while in subdirectory' '
+       git reset --hard &&
+       git checkout master &&
+       mkdir subs &&
+       (
+               cd subs &&
+               git checkout side
+       ) &&
+       ! test -f subs/one &&
+       rm -fr subs
+ '
+ test_expect_success 'checkout specific path while in subdirectory' '
+       git reset --hard &&
+       git checkout side &&
+       mkdir subs &&
+       >subs/bero &&
+       git add subs/bero &&
+       git commit -m "add subs/bero" &&
+       git checkout master &&
+       mkdir -p subs &&
+       (
+               cd subs &&
+               git checkout side -- bero
+       ) &&
+       test -f subs/bero
+ '
  test_done
diff --combined unpack-trees.c
index 56c1ffbc199c534a53da9615aa16b4357656e320,470fa02e0886462f44fd0e188da6e8c65ab6fac0..3e448d8974eb6d738fec2c35cc5a9ffbc8764411
@@@ -85,6 -85,7 +85,7 @@@ static int unpack_trees_rec(struct tree
                int any_dirs = 0;
                char *cache_name;
                int ce_stage;
+               int skip_entry = 0;
  
                /* Find the first name in the input. */
  
  
  #if DBRT_DEBUG > 1
                if (first)
-                       printf("index %s\n", first);
+                       fprintf(stderr, "index %s\n", first);
  #endif
                for (i = 0; i < len; i++) {
                        if (!posns[i] || posns[i] == df_conflict_list)
                                continue;
  #if DBRT_DEBUG > 1
-                       printf("%d %s\n", i + 1, posns[i]->name);
+                       fprintf(stderr, "%d %s\n", i + 1, posns[i]->name);
  #endif
                        if (!first || entcmp(first, firstdir,
                                             posns[i]->name,
                        any_files = 1;
                        src[0] = active_cache[o->pos];
                        remove = o->pos;
+                       if (o->skip_unmerged && ce_stage(src[0]))
+                               skip_entry = 1;
                }
  
                for (i = 0; i < len; i++) {
                                continue;
                        }
  
+                       if (skip_entry) {
+                               subposns[i] = df_conflict_list;
+                               posns[i] = posns[i]->next;
+                               continue;
+                       }
                        if (!o->merge)
                                ce_stage = 0;
                        else if (i + 1 < o->head_idx)
                        posns[i] = posns[i]->next;
                }
                if (any_files) {
-                       if (o->merge) {
+                       if (skip_entry) {
+                               o->pos++;
+                               while (o->pos < active_nr &&
+                                      !strcmp(active_cache[o->pos]->name,
+                                              src[0]->name))
+                                       o->pos++;
+                       } else if (o->merge) {
                                int ret;
  
  #if DBRT_DEBUG > 1
-                               printf("%s:\n", first);
+                               fprintf(stderr, "%s:\n", first);
                                for (i = 0; i < src_size; i++) {
-                                       printf(" %d ", i);
+                                       fprintf(stderr, " %d ", i);
                                        if (src[i])
-                                               printf("%s\n", sha1_to_hex(src[i]->sha1));
+                                               fprintf(stderr, "%06x %s\n", src[i]->ce_mode, sha1_to_hex(src[i]->sha1));
                                        else
-                                               printf("\n");
+                                               fprintf(stderr, "\n");
                                }
  #endif
                                ret = o->fn(src, o, remove);
+                               if (ret < 0)
+                                       return ret;
  
  #if DBRT_DEBUG > 1
-                               printf("Added %d entries\n", ret);
+                               fprintf(stderr, "Added %d entries\n", ret);
  #endif
                                o->pos += ret;
                        } else {
@@@ -286,34 -303,36 +303,36 @@@ static void unlink_entry(char *name, ch
  }
  
  static struct checkout state;
- static void check_updates(struct cache_entry **src, int nr,
-                       struct unpack_trees_options *o)
+ static void check_updates(struct unpack_trees_options *o)
  {
        unsigned cnt = 0, total = 0;
        struct progress *progress = NULL;
        char last_symlink[PATH_MAX];
+       int i;
  
        if (o->update && o->verbose_update) {
-               for (total = cnt = 0; cnt < nr; cnt++) {
-                       struct cache_entry *ce = src[cnt];
+               for (total = cnt = 0; cnt < active_nr; cnt++) {
+                       struct cache_entry *ce = active_cache[cnt];
                        if (ce->ce_flags & (CE_UPDATE | CE_REMOVE))
                                total++;
                }
  
                progress = start_progress_delay("Checking out files",
 -                                              total, 50, 2);
 +                                              total, 50, 1);
                cnt = 0;
        }
  
        *last_symlink = '\0';
-       while (nr--) {
-               struct cache_entry *ce = *src++;
+       for (i = 0; i < active_nr; i++) {
+               struct cache_entry *ce = active_cache[i];
  
                if (ce->ce_flags & (CE_UPDATE | CE_REMOVE))
                        display_progress(progress, ++cnt);
                if (ce->ce_flags & CE_REMOVE) {
                        if (o->update)
                                unlink_entry(ce->name, last_symlink);
+                       remove_cache_entry_at(i);
+                       i--;
                        continue;
                }
                if (ce->ce_flags & CE_UPDATE) {
@@@ -354,23 -373,34 +373,34 @@@ int unpack_trees(unsigned len, struct t
                        posns[i] = create_tree_entry_list(t+i);
  
                if (unpack_trees_rec(posns, len, o->prefix ? o->prefix : "",
-                                    o, &df_conflict_list))
+                                    o, &df_conflict_list)) {
+                       if (o->gently) {
+                               discard_cache();
+                               read_cache();
+                       }
                        return -1;
+               }
        }
  
-       if (o->trivial_merges_only && o->nontrivial_merge)
-               die("Merge requires file-level merging");
+       if (o->trivial_merges_only && o->nontrivial_merge) {
+               if (o->gently) {
+                       discard_cache();
+                       read_cache();
+               }
+               return o->gently ? -1 :
+                       error("Merge requires file-level merging");
+       }
  
-       check_updates(active_cache, active_nr, o);
+       check_updates(o);
        return 0;
  }
  
  /* Here come the merge functions */
  
- static void reject_merge(struct cache_entry *ce)
+ static int reject_merge(struct cache_entry *ce)
  {
-       die("Entry '%s' would be overwritten by merge. Cannot merge.",
-           ce->name);
+       return error("Entry '%s' would be overwritten by merge. Cannot merge.",
+                    ce->name);
  }
  
  static int same(struct cache_entry *a, struct cache_entry *b)
   * When a CE gets turned into an unmerged entry, we
   * want it to be up-to-date
   */
- static void verify_uptodate(struct cache_entry *ce,
+ static int verify_uptodate(struct cache_entry *ce,
                struct unpack_trees_options *o)
  {
        struct stat st;
  
        if (o->index_only || o->reset)
-               return;
+               return 0;
  
        if (!lstat(ce->name, &st)) {
                unsigned changed = ce_match_stat(ce, &st, CE_MATCH_IGNORE_VALID);
                if (!changed)
-                       return;
+                       return 0;
                /*
                 * NEEDSWORK: the current default policy is to allow
                 * submodule to be out of sync wrt the supermodule
                 * checked out.
                 */
                if (S_ISGITLINK(ce->ce_mode))
-                       return;
+                       return 0;
                errno = 0;
        }
        if (errno == ENOENT)
-               return;
-       die("Entry '%s' not uptodate. Cannot merge.", ce->name);
+               return 0;
+       return o->gently ? -1 :
+               error("Entry '%s' not uptodate. Cannot merge.", ce->name);
  }
  
  static void invalidate_ce_path(struct cache_entry *ce)
@@@ -479,7 -510,8 +510,8 @@@ static int verify_clean_subdirectory(st
                 * ce->name is an entry in the subdirectory.
                 */
                if (!ce_stage(ce)) {
-                       verify_uptodate(ce, o);
+                       if (verify_uptodate(ce, o))
+                               return -1;
                        ce->ce_flags |= CE_REMOVE;
                }
                cnt++;
                d.exclude_per_dir = o->dir->exclude_per_dir;
        i = read_directory(&d, ce->name, pathbuf, namelen+1, NULL);
        if (i)
-               die("Updating '%s' would lose untracked files in it",
-                   ce->name);
+               return o->gently ? -1 :
+                       error("Updating '%s' would lose untracked files in it",
+                             ce->name);
        free(pathbuf);
        return cnt;
  }
   * We do not want to remove or overwrite a working tree file that
   * is not tracked, unless it is ignored.
   */
- static void verify_absent(struct cache_entry *ce, const char *action,
-               struct unpack_trees_options *o)
+ static int verify_absent(struct cache_entry *ce, const char *action,
+                        struct unpack_trees_options *o)
  {
        struct stat st;
  
        if (o->index_only || o->reset || !o->update)
-               return;
+               return 0;
  
        if (has_symlink_leading_path(ce->name, NULL))
-               return;
+               return 0;
  
        if (!lstat(ce->name, &st)) {
                int cnt;
 +              int dtype = ce_to_dtype(ce);
  
 -              if (o->dir && excluded(o->dir, ce->name))
 +              if (o->dir && excluded(o->dir, ce->name, &dtype))
                        /*
                         * ce->name is explicitly excluded, so it is Ok to
                         * overwrite it.
                         */
-                       return;
+                       return 0;
                if (S_ISDIR(st.st_mode)) {
                        /*
                         * We are checking out path "foo" and
                         * deleted entries here.
                         */
                        o->pos += cnt;
-                       return;
+                       return 0;
                }
  
                /*
                if (0 <= cnt) {
                        struct cache_entry *ce = active_cache[cnt];
                        if (ce->ce_flags & CE_REMOVE)
-                               return;
+                               return 0;
                }
  
-               die("Untracked working tree file '%s' "
-                   "would be %s by merge.", ce->name, action);
+               return o->gently ? -1 :
+                       error("Untracked working tree file '%s' "
+                             "would be %s by merge.", ce->name, action);
        }
+       return 0;
  }
  
  static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
                 * a match.
                 */
                if (same(old, merge)) {
 -                      memcpy(merge, old, offsetof(struct cache_entry, name));
 +                      copy_cache_entry(merge, old);
                } else {
-                       verify_uptodate(old, o);
+                       if (verify_uptodate(old, o))
+                               return -1;
                        invalidate_ce_path(old);
                }
        }
        else {
-               verify_absent(merge, "overwritten", o);
+               if (verify_absent(merge, "overwritten", o))
+                       return -1;
                invalidate_ce_path(merge);
        }
  
  static int deleted_entry(struct cache_entry *ce, struct cache_entry *old,
                struct unpack_trees_options *o)
  {
-       if (old)
-               verify_uptodate(old, o);
-       else
-               verify_absent(ce, "removed", o);
+       if (old) {
+               if (verify_uptodate(old, o))
+                       return -1;
+       } else
+               if (verify_absent(ce, "removed", o))
+                       return -1;
        ce->ce_flags |= CE_REMOVE;
        add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
        invalidate_ce_path(ce);
@@@ -700,16 -738,15 +739,15 @@@ int threeway_merge(struct cache_entry *
        /* #14, #14ALT, #2ALT */
        if (remote && !df_conflict_head && head_match && !remote_match) {
                if (index && !same(index, remote) && !same(index, head))
-                       reject_merge(index);
+                       return o->gently ? -1 : reject_merge(index);
                return merged_entry(remote, index, o);
        }
        /*
         * If we have an entry in the index cache, then we want to
         * make sure that it matches head.
         */
-       if (index && !same(index, head)) {
-               reject_merge(index);
-       }
+       if (index && !same(index, head))
+               return o->gently ? -1 : reject_merge(index);
  
        if (head) {
                /* #5ALT, #15 */
                        remove_entry(remove);
                        if (index)
                                return deleted_entry(index, index, o);
-                       else if (ce && !head_deleted)
-                               verify_absent(ce, "removed", o);
+                       else if (ce && !head_deleted) {
+                               if (verify_absent(ce, "removed", o))
+                                       return -1;
+                       }
                        return 0;
                }
                /*
         * conflict resolution files.
         */
        if (index) {
-               verify_uptodate(index, o);
+               if (verify_uptodate(index, o))
+                       return -1;
        }
  
        remove_entry(remove);
@@@ -856,11 -896,11 +897,11 @@@ int twoway_merge(struct cache_entry **s
                        /* all other failures */
                        remove_entry(remove);
                        if (oldtree)
-                               reject_merge(oldtree);
+                               return o->gently ? -1 : reject_merge(oldtree);
                        if (current)
-                               reject_merge(current);
+                               return o->gently ? -1 : reject_merge(current);
                        if (newtree)
-                               reject_merge(newtree);
+                               return o->gently ? -1 : reject_merge(newtree);
                        return -1;
                }
        }
@@@ -887,7 -927,8 +928,8 @@@ int bind_merge(struct cache_entry **src
                return error("Cannot do a bind merge of %d trees\n",
                             o->merge_size);
        if (a && old)
-               die("Entry '%s' overlaps.  Cannot bind.", a->name);
+               return o->gently ? -1 :
+                       error("Entry '%s' overlaps.  Cannot bind.", a->name);
        if (!a)
                return keep_entry(old, o);
        else