rebase: Support preserving merges in non-interactive mode
[gitweb.git] / builtin-checkout.c
index 16bfbb66055951e44c19410b6c889b3aa63891ec..b572b3bf69c791912717eae313942316cd77ac37 100644 (file)
@@ -13,6 +13,9 @@
 #include "diff.h"
 #include "revision.h"
 #include "remote.h"
+#include "blob.h"
+#include "xdiff-interface.h"
+#include "ll-merge.h"
 
 static const char * const checkout_usage[] = {
        "git checkout [options] <branch>",
@@ -109,6 +112,19 @@ static int check_stage(int stage, struct cache_entry *ce, int pos)
                     (stage == 2) ? "our" : "their");
 }
 
+static int check_all_stages(struct cache_entry *ce, int pos)
+{
+       if (ce_stage(ce) != 1 ||
+           active_nr <= pos + 2 ||
+           strcmp(active_cache[pos+1]->name, ce->name) ||
+           ce_stage(active_cache[pos+1]) != 2 ||
+           strcmp(active_cache[pos+2]->name, ce->name) ||
+           ce_stage(active_cache[pos+2]) != 3)
+               return error("path '%s' does not have all three versions",
+                            ce->name);
+       return 0;
+}
+
 static int checkout_stage(int stage, struct cache_entry *ce, int pos,
                          struct checkout *state)
 {
@@ -123,6 +139,77 @@ static int checkout_stage(int stage, struct cache_entry *ce, int pos,
                     (stage == 2) ? "our" : "their");
 }
 
+/* NEEDSWORK: share with merge-recursive */
+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;
+}
+
+static int checkout_merged(int pos, struct checkout *state)
+{
+       struct cache_entry *ce = active_cache[pos];
+       const char *path = ce->name;
+       mmfile_t ancestor, ours, theirs;
+       int status;
+       unsigned char sha1[20];
+       mmbuffer_t result_buf;
+
+       if (ce_stage(ce) != 1 ||
+           active_nr <= pos + 2 ||
+           strcmp(active_cache[pos+1]->name, path) ||
+           ce_stage(active_cache[pos+1]) != 2 ||
+           strcmp(active_cache[pos+2]->name, path) ||
+           ce_stage(active_cache[pos+2]) != 3)
+               return error("path '%s' does not have all 3 versions", path);
+
+       fill_mm(active_cache[pos]->sha1, &ancestor);
+       fill_mm(active_cache[pos+1]->sha1, &ours);
+       fill_mm(active_cache[pos+2]->sha1, &theirs);
+
+       status = ll_merge(&result_buf, path, &ancestor,
+                         &ours, "ours", &theirs, "theirs", 1);
+       free(ancestor.ptr);
+       free(ours.ptr);
+       free(theirs.ptr);
+       if (status < 0 || !result_buf.ptr) {
+               free(result_buf.ptr);
+               return error("path '%s': cannot merge", path);
+       }
+
+       /*
+        * NEEDSWORK:
+        * There is absolutely no reason to write this as a blob object
+        * and create a phoney cache entry just to leak.  This hack is
+        * primarily to get to the write_entry() machinery that massages
+        * the contents to work-tree format and writes out which only
+        * allows it for a cache entry.  The code in write_entry() needs
+        * to be refactored to allow us to feed a <buffer, size, mode>
+        * instead of a cache entry.  Such a refactoring would help
+        * merge_recursive as well (it also writes the merge result to the
+        * object database even when it may contain conflicts).
+        */
+       if (write_sha1_file(result_buf.ptr, result_buf.size,
+                           blob_type, sha1))
+               die("Unable to add merge result for '%s'", path);
+       ce = make_cache_entry(create_ce_mode(active_cache[pos+1]->ce_mode),
+                             sha1,
+                             path, 2, 0);
+       status = checkout_entry(ce, state, NULL);
+       return status;
+}
+
 static int checkout_paths(struct tree *source_tree, const char **pathspec,
                          struct checkout_opts *opts)
 {
@@ -134,6 +221,7 @@ static int checkout_paths(struct tree *source_tree, const char **pathspec,
        struct commit *head;
        int errs = 0;
        int stage = opts->writeout_stage;
+       int merge = opts->merge;
        int newfd;
        struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 
@@ -165,6 +253,8 @@ static int checkout_paths(struct tree *source_tree, const char **pathspec,
                                warning("path '%s' is unmerged", ce->name);
                        } else if (stage) {
                                errs |= check_stage(stage, ce, pos);
+                       } else if (opts->merge) {
+                               errs |= check_all_stages(ce, pos);
                        } else {
                                errs = 1;
                                error("path '%s' is unmerged", ce->name);
@@ -188,6 +278,8 @@ static int checkout_paths(struct tree *source_tree, const char **pathspec,
                        }
                        if (stage)
                                errs |= checkout_stage(stage, ce, pos, &state);
+                       else if (merge)
+                               errs |= checkout_merged(pos, &state);
                        pos = skip_same_name(ce, pos) - 1;
                }
        }
@@ -305,6 +397,8 @@ static int merge_working_tree(struct checkout_opts *opts,
                }
 
                /* 2-way merge to the new branch */
+               topts.initial_checkout = (!active_nr &&
+                                         (old->commit == new->commit));
                topts.update = 1;
                topts.merge = 1;
                topts.gently = opts->merge;
@@ -327,6 +421,7 @@ static int merge_working_tree(struct checkout_opts *opts,
                         */
                        struct tree *result;
                        struct tree *work;
+                       struct merge_options o;
                        if (!opts->merge)
                                return 1;
                        parse_commit(old->commit);
@@ -345,13 +440,17 @@ static int merge_working_tree(struct checkout_opts *opts,
                         */
 
                        add_files_to_cache(NULL, NULL, 0);
-                       work = write_tree_from_memory();
+                       init_merge_options(&o);
+                       o.verbosity = 0;
+                       work = write_tree_from_memory(&o);
 
                        ret = reset_tree(new->commit->tree, opts, 1);
                        if (ret)
                                return ret;
-                       merge_trees(new->commit->tree, work, old->commit->tree,
-                                   new->name, "local", &result);
+                       o.branch1 = new->name;
+                       o.branch2 = "local";
+                       merge_trees(&o, new->commit->tree, work,
+                               old->commit->tree, &result);
                        ret = reset_tree(new->commit->tree, opts, 0);
                        if (ret)
                                return ret;
@@ -362,7 +461,7 @@ static int merge_working_tree(struct checkout_opts *opts,
            commit_locked_index(lock_file))
                die("unable to write new index file");
 
-       if (!opts->force)
+       if (!opts->force && !opts->quiet)
                show_local_changes(&new->commit->object);
 
        return 0;
@@ -449,13 +548,11 @@ static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
        }
 
        /*
-        * If the new thing isn't a branch and isn't HEAD and we're
-        * not starting a new branch, and we want messages, and we
-        * weren't on a branch, and we're moving to a new commit,
-        * describe the old commit.
+        * If we were on a detached HEAD, but we are now moving to
+        * a new commit, we want to mention the old commit once more
+        * to remind the user that it might be lost.
         */
-       if (!new->path && strcmp(new->name, "HEAD") && !opts->new_branch &&
-           !opts->quiet && !old.path && new->commit != old.commit)
+       if (!opts->quiet && !old.path && new->commit != old.commit)
                describe_detached_head("Previous HEAD position was", old.commit);
 
        if (!old.commit) {
@@ -476,6 +573,11 @@ static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
        return ret || opts->writeout_error;
 }
 
+static int git_checkout_config(const char *var, const char *value, void *cb)
+{
+       return git_xmerge_config(var, value, cb);
+}
+
 int cmd_checkout(int argc, const char **argv, const char *prefix)
 {
        struct checkout_opts opts;
@@ -483,6 +585,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
        const char *arg;
        struct branch_info new;
        struct tree *source_tree = NULL;
+       char *conflict_style = NULL;
        struct option options[] = {
                OPT__QUIET(&opts.quiet),
                OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
@@ -494,7 +597,9 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                OPT_SET_INT('3', "theirs", &opts.writeout_stage, "stage",
                            3),
                OPT_BOOLEAN('f', NULL, &opts.force, "force"),
-               OPT_BOOLEAN('m', NULL, &opts.merge, "merge"),
+               OPT_BOOLEAN('m', "merge", &opts.merge, "merge"),
+               OPT_STRING(0, "conflict", &conflict_style, "style",
+                          "conflict style (merge or diff3)"),
                OPT_END(),
        };
        int has_dash_dash;
@@ -502,13 +607,35 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
        memset(&opts, 0, sizeof(opts));
        memset(&new, 0, sizeof(new));
 
-       git_config(git_default_config, NULL);
+       git_config(git_checkout_config, NULL);
 
-       opts.track = git_branch_track;
+       opts.track = BRANCH_TRACK_UNSPECIFIED;
 
        argc = parse_options(argc, argv, options, checkout_usage,
                             PARSE_OPT_KEEP_DASHDASH);
 
+       /* --track without -b should DWIM */
+       if (0 < opts.track && !opts.new_branch) {
+               const char *argv0 = argv[0];
+               if (!argc || !strcmp(argv0, "--"))
+                       die ("--track needs a branch name");
+               if (!prefixcmp(argv0, "refs/"))
+                       argv0 += 5;
+               if (!prefixcmp(argv0, "remotes/"))
+                       argv0 += 8;
+               argv0 = strchr(argv0, '/');
+               if (!argv0 || !argv0[1])
+                       die ("Missing branch name; try -b");
+               opts.new_branch = argv0 + 1;
+       }
+
+       if (opts.track == BRANCH_TRACK_UNSPECIFIED)
+               opts.track = git_branch_track;
+       if (conflict_style) {
+               opts.merge = 1; /* implied */
+               git_xmerge_config("merge.conflictstyle", conflict_style, NULL);
+       }
+
        if (!opts.new_branch && (opts.track != git_branch_track))
                die("git checkout: --track and --no-track require -b");
 
@@ -594,7 +721,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                        die("invalid path specification");
 
                /* Checkout paths */
-               if (opts.new_branch || opts.merge) {
+               if (opts.new_branch) {
                        if (argc == 1) {
                                die("git checkout: updating paths is incompatible with switching branches.\nDid you intend to checkout '%s' which can not be resolved as commit?", argv[0]);
                        } else {
@@ -602,9 +729,24 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                        }
                }
 
+               if (1 < !!opts.writeout_stage + !!opts.force + !!opts.merge)
+                       die("git checkout: --ours/--theirs, --force and --merge are incompatible when\nchecking out of the index.");
+
                return checkout_paths(source_tree, pathspec, &opts);
        }
 
+       if (opts.new_branch) {
+               struct strbuf buf;
+               strbuf_init(&buf, 0);
+               strbuf_addstr(&buf, "refs/heads/");
+               strbuf_addstr(&buf, opts.new_branch);
+               if (!get_sha1(buf.buf, rev))
+                       die("git checkout: branch %s already exists", opts.new_branch);
+               if (check_ref_format(buf.buf))
+                       die("git checkout: we do not like '%s' as a branch name.", opts.new_branch);
+               strbuf_release(&buf);
+       }
+
        if (new.name && !new.commit) {
                die("Cannot switch branch to a non-commit.");
        }