Merge branch 'mm/maint-log-n-with-diff-filtering'
[gitweb.git] / builtin / checkout.c
index 757f9a08ddbaf102726a781b06d7294a4638984e..2bf02f2841a84a2a86de08e53328dbbb87ff3587 100644 (file)
@@ -30,6 +30,7 @@ struct checkout_opts {
        int quiet;
        int merge;
        int force;
+       int force_detach;
        int writeout_stage;
        int writeout_error;
 
@@ -297,7 +298,7 @@ static void show_local_changes(struct object *head, struct diff_options *opts)
        run_diff_index(&rev, 0);
 }
 
-static void describe_detached_head(char *msg, struct commit *commit)
+static void describe_detached_head(const char *msg, struct commit *commit)
 {
        struct strbuf sb = STRBUF_INIT;
        struct pretty_print_context ctx = {0};
@@ -404,7 +405,7 @@ static int merge_working_tree(struct checkout_opts *opts,
                topts.dir->exclude_per_dir = ".gitignore";
                tree = parse_tree_indirect(old->commit ?
                                           old->commit->object.sha1 :
-                                          (unsigned char *)EMPTY_TREE_SHA1_BIN);
+                                          EMPTY_TREE_SHA1_BIN);
                init_tree_desc(&trees[0], tree->buffer, tree->size);
                tree = parse_tree_indirect(new->commit->object.sha1);
                init_tree_desc(&trees[1], tree->buffer, tree->size);
@@ -541,7 +542,17 @@ static void update_refs_for_switch(struct checkout_opts *opts,
        strbuf_addf(&msg, "checkout: moving from %s to %s",
                    old_desc ? old_desc : "(invalid)", new->name);
 
-       if (new->path) {
+       if (!strcmp(new->name, "HEAD") && !new->path && !opts->force_detach) {
+               /* Nothing to do. */
+       } else if (opts->force_detach || !new->path) {  /* No longer on any branch. */
+               update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
+                          REF_NODEREF, DIE_ON_ERR);
+               if (!opts->quiet) {
+                       if (old->path && advice_detached_head)
+                               detach_advice(old->path, new->name);
+                       describe_detached_head("HEAD is now at", new->commit);
+               }
+       } else if (new->path) { /* Switch branches. */
                create_symref("HEAD", new->path, msg.buf);
                if (!opts->quiet) {
                        if (old->path && !strcmp(new->path, old->path))
@@ -563,21 +574,108 @@ static void update_refs_for_switch(struct checkout_opts *opts,
                        if (!file_exists(ref_file) && file_exists(log_file))
                                remove_path(log_file);
                }
-       } else if (strcmp(new->name, "HEAD")) {
-               update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
-                          REF_NODEREF, DIE_ON_ERR);
-               if (!opts->quiet) {
-                       if (old->path && advice_detached_head)
-                               detach_advice(old->path, new->name);
-                       describe_detached_head("HEAD is now at", new->commit);
-               }
        }
        remove_branch_state();
        strbuf_release(&msg);
-       if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
+       if (!opts->quiet &&
+           (new->path || (!opts->force_detach && !strcmp(new->name, "HEAD"))))
                report_tracking(new);
 }
 
+struct rev_list_args {
+       int argc;
+       int alloc;
+       const char **argv;
+};
+
+static void add_one_rev_list_arg(struct rev_list_args *args, const char *s)
+{
+       ALLOC_GROW(args->argv, args->argc + 1, args->alloc);
+       args->argv[args->argc++] = s;
+}
+
+static int add_one_ref_to_rev_list_arg(const char *refname,
+                                      const unsigned char *sha1,
+                                      int flags,
+                                      void *cb_data)
+{
+       add_one_rev_list_arg(cb_data, refname);
+       return 0;
+}
+
+
+static void describe_one_orphan(struct strbuf *sb, struct commit *commit)
+{
+       struct pretty_print_context ctx = { 0 };
+
+       parse_commit(commit);
+       strbuf_addstr(sb, " - ");
+       pretty_print_commit(CMIT_FMT_ONELINE, commit, sb, &ctx);
+       strbuf_addch(sb, '\n');
+}
+
+#define ORPHAN_CUTOFF 4
+static void suggest_reattach(struct commit *commit, struct rev_info *revs)
+{
+       struct commit *c, *last = NULL;
+       struct strbuf sb = STRBUF_INIT;
+       int lost = 0;
+       while ((c = get_revision(revs)) != NULL) {
+               if (lost < ORPHAN_CUTOFF)
+                       describe_one_orphan(&sb, c);
+               last = c;
+               lost++;
+       }
+       if (ORPHAN_CUTOFF < lost) {
+               int more = lost - ORPHAN_CUTOFF;
+               if (more == 1)
+                       describe_one_orphan(&sb, last);
+               else
+                       strbuf_addf(&sb, " ... and %d more.\n", more);
+       }
+
+       fprintf(stderr,
+               "Warning: you are leaving %d commit%s behind, "
+               "not connected to\n"
+               "any of your branches:\n\n"
+               "%s\n"
+               "If you want to keep them by creating a new branch, "
+               "this may be a good time\nto do so with:\n\n"
+               " git branch new_branch_name %s\n\n",
+               lost, ((1 < lost) ? "s" : ""),
+               sb.buf,
+               sha1_to_hex(commit->object.sha1));
+       strbuf_release(&sb);
+}
+
+/*
+ * We are about to leave commit that was at the tip of a detached
+ * HEAD.  If it is not reachable from any ref, this is the last chance
+ * for the user to do so without resorting to reflog.
+ */
+static void orphaned_commit_warning(struct commit *commit)
+{
+       struct rev_list_args args = { 0, 0, NULL };
+       struct rev_info revs;
+
+       add_one_rev_list_arg(&args, "(internal)");
+       add_one_rev_list_arg(&args, sha1_to_hex(commit->object.sha1));
+       add_one_rev_list_arg(&args, "--not");
+       for_each_ref(add_one_ref_to_rev_list_arg, &args);
+       add_one_rev_list_arg(&args, "--");
+       add_one_rev_list_arg(&args, NULL);
+
+       init_revisions(&revs, NULL);
+       if (setup_revisions(args.argc - 1, args.argv, &revs, NULL) != 1)
+               die("internal error: only -- alone should have been left");
+       if (prepare_revision_walk(&revs))
+               die("internal error in revision walk");
+       if (!(commit->object.flags & UNINTERESTING))
+               suggest_reattach(commit, &revs);
+       else
+               describe_detached_head("Previous HEAD position was", commit);
+}
+
 static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
 {
        int ret = 0;
@@ -605,13 +703,8 @@ static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
        if (ret)
                return ret;
 
-       /*
-        * If we were on a detached HEAD, but have now moved to
-        * a new commit, we want to mention the old commit once more
-        * to remind the user that it might be lost.
-        */
        if (!opts->quiet && !old.path && old.commit && new->commit != old.commit)
-               describe_detached_head("Previous HEAD position was", old.commit);
+               orphaned_commit_warning(old.commit);
 
        update_refs_for_switch(opts, &old, new);
 
@@ -675,11 +768,123 @@ static const char *unique_tracking_name(const char *name)
        return NULL;
 }
 
+static int parse_branchname_arg(int argc, const char **argv,
+                               int dwim_new_local_branch_ok,
+                               struct branch_info *new,
+                               struct tree **source_tree,
+                               unsigned char rev[20],
+                               const char **new_branch)
+{
+       int argcount = 0;
+       unsigned char branch_rev[20];
+       const char *arg;
+       int has_dash_dash;
+
+       /*
+        * case 1: git checkout <ref> -- [<paths>]
+        *
+        *   <ref> must be a valid tree, everything after the '--' must be
+        *   a path.
+        *
+        * case 2: git checkout -- [<paths>]
+        *
+        *   everything after the '--' must be paths.
+        *
+        * case 3: git checkout <something> [<paths>]
+        *
+        *   With no paths, if <something> is a commit, that is to
+        *   switch to the branch or detach HEAD at it.  As a special case,
+        *   if <something> is A...B (missing A or B means HEAD but you can
+        *   omit at most one side), and if there is a unique merge base
+        *   between A and B, A...B names that merge base.
+        *
+        *   With no paths, if <something> is _not_ a commit, no -t nor -b
+        *   was given, and there is a tracking branch whose name is
+        *   <something> in one and only one remote, then this is a short-hand
+        *   to fork local <something> from that remote-tracking branch.
+        *
+        *   Otherwise <something> shall not be ambiguous.
+        *   - If it's *only* a reference, treat it like case (1).
+        *   - If it's only a path, treat it like case (2).
+        *   - else: fail.
+        *
+        */
+       if (!argc)
+               return 0;
+
+       if (!strcmp(argv[0], "--"))     /* case (2) */
+               return 1;
+
+       arg = argv[0];
+       has_dash_dash = (argc > 1) && !strcmp(argv[1], "--");
+
+       if (!strcmp(arg, "-"))
+               arg = "@{-1}";
+
+       if (get_sha1_mb(arg, rev)) {
+               if (has_dash_dash)          /* case (1) */
+                       die("invalid reference: %s", arg);
+               if (dwim_new_local_branch_ok &&
+                   !check_filename(NULL, arg) &&
+                   argc == 1) {
+                       const char *remote = unique_tracking_name(arg);
+                       if (!remote || get_sha1(remote, rev))
+                               return argcount;
+                       *new_branch = arg;
+                       arg = remote;
+                       /* DWIMmed to create local branch */
+               } else {
+                       return argcount;
+               }
+       }
+
+       /* we can't end up being in (2) anymore, eat the argument */
+       argcount++;
+       argv++;
+       argc--;
+
+       new->name = arg;
+       setup_branch_path(new);
+
+       if (check_ref_format(new->path) == CHECK_REF_FORMAT_OK &&
+           resolve_ref(new->path, branch_rev, 1, NULL))
+               hashcpy(rev, branch_rev);
+       else
+               new->path = NULL; /* not an existing branch */
+
+       new->commit = lookup_commit_reference_gently(rev, 1);
+       if (!new->commit) {
+               /* not a commit */
+               *source_tree = parse_tree_indirect(rev);
+       } else {
+               parse_commit(new->commit);
+               *source_tree = new->commit->tree;
+       }
+
+       if (!*source_tree)                   /* case (1): want a tree */
+               die("reference is not a tree: %s", arg);
+       if (!has_dash_dash) {/* case (3 -> 1) */
+               /*
+                * Do not complain the most common case
+                *      git checkout branch
+                * even if there happen to be a file called 'branch';
+                * it would be extremely annoying.
+                */
+               if (argc)
+                       verify_non_filename(NULL, arg);
+       } else {
+               argcount++;
+               argv++;
+               argc--;
+       }
+
+       return argcount;
+}
+
 int cmd_checkout(int argc, const char **argv, const char *prefix)
 {
        struct checkout_opts opts;
        unsigned char rev[20];
-       const char *arg;
        struct branch_info new;
        struct tree *source_tree = NULL;
        char *conflict_style = NULL;
@@ -692,6 +897,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                OPT_STRING('B', NULL, &opts.new_branch_force, "branch",
                           "create/reset and checkout a branch"),
                OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "create reflog for new branch"),
+               OPT_BOOLEAN(0, "detach", &opts.force_detach, "detach the HEAD at named commit"),
                OPT_SET_INT('t', "track",  &opts.track, "set upstream info for new branch",
                        BRANCH_TRACK_EXPLICIT),
                OPT_STRING(0, "orphan", &opts.new_orphan_branch, "new branch", "new unparented branch"),
@@ -709,7 +915,6 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                  PARSE_OPT_NOARG | PARSE_OPT_HIDDEN },
                OPT_END(),
        };
-       int has_dash_dash;
 
        memset(&opts, 0, sizeof(opts));
        memset(&new, 0, sizeof(new));
@@ -731,9 +936,15 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                opts.new_branch = opts.new_branch_force;
 
        if (patch_mode && (opts.track > 0 || opts.new_branch
-                          || opts.new_branch_log || opts.merge || opts.force))
+                          || opts.new_branch_log || opts.merge || opts.force
+                          || opts.force_detach))
                die ("--patch is incompatible with all other options");
 
+       if (opts.force_detach && (opts.new_branch || opts.new_orphan_branch))
+               die("--detach cannot be used with -b/-B/--orphan");
+       if (opts.force_detach && 0 < opts.track)
+               die("--detach cannot be used with -t");
+
        /* --track without -b should DWIM */
        if (0 < opts.track && !opts.new_branch) {
                const char *argv0 = argv[0];
@@ -766,105 +977,30 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                die("git checkout: -f and -m are incompatible");
 
        /*
-        * case 1: git checkout <ref> -- [<paths>]
-        *
-        *   <ref> must be a valid tree, everything after the '--' must be
-        *   a path.
-        *
-        * case 2: git checkout -- [<paths>]
-        *
-        *   everything after the '--' must be paths.
-        *
-        * case 3: git checkout <something> [<paths>]
-        *
-        *   With no paths, if <something> is a commit, that is to
-        *   switch to the branch or detach HEAD at it.  As a special case,
-        *   if <something> is A...B (missing A or B means HEAD but you can
-        *   omit at most one side), and if there is a unique merge base
-        *   between A and B, A...B names that merge base.
+        * Extract branch name from command line arguments, so
+        * all that is left is pathspecs.
         *
-        *   With no paths, if <something> is _not_ a commit, no -t nor -b
-        *   was given, and there is a remote-tracking branch whose name is
-        *   <something> in one and only one remote, then this is a short-hand
-        *   to fork local <something> from that remote-tracking branch.
+        * Handle
         *
-        *   Otherwise <something> shall not be ambiguous.
-        *   - If it's *only* a reference, treat it like case (1).
-        *   - If it's only a path, treat it like case (2).
-        *   - else: fail.
+        *  1) git checkout <tree> -- [<paths>]
+        *  2) git checkout -- [<paths>]
+        *  3) git checkout <something> [<paths>]
         *
+        * including "last branch" syntax and DWIM-ery for names of
+        * remote branches, erroring out for invalid or ambiguous cases.
         */
        if (argc) {
-               if (!strcmp(argv[0], "--")) {       /* case (2) */
-                       argv++;
-                       argc--;
-                       goto no_reference;
-               }
-
-               arg = argv[0];
-               has_dash_dash = (argc > 1) && !strcmp(argv[1], "--");
-
-               if (!strcmp(arg, "-"))
-                       arg = "@{-1}";
-
-               if (get_sha1_mb(arg, rev)) {
-                       if (has_dash_dash)          /* case (1) */
-                               die("invalid reference: %s", arg);
-                       if (!patch_mode &&
-                           dwim_new_local_branch &&
-                           opts.track == BRANCH_TRACK_UNSPECIFIED &&
-                           !opts.new_branch &&
-                           !check_filename(NULL, arg) &&
-                           argc == 1) {
-                               const char *remote = unique_tracking_name(arg);
-                               if (!remote || get_sha1(remote, rev))
-                                       goto no_reference;
-                               opts.new_branch = arg;
-                               arg = remote;
-                               /* DWIMmed to create local branch */
-                       }
-                       else
-                               goto no_reference;
-               }
-
-               /* we can't end up being in (2) anymore, eat the argument */
-               argv++;
-               argc--;
-
-               new.name = arg;
-               if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
-                       setup_branch_path(&new);
-
-                       if ((check_ref_format(new.path) == CHECK_REF_FORMAT_OK) &&
-                           resolve_ref(new.path, rev, 1, NULL))
-                               ;
-                       else
-                               new.path = NULL;
-                       parse_commit(new.commit);
-                       source_tree = new.commit->tree;
-               } else
-                       source_tree = parse_tree_indirect(rev);
-
-               if (!source_tree)                   /* case (1): want a tree */
-                       die("reference is not a tree: %s", arg);
-               if (!has_dash_dash) {/* case (3 -> 1) */
-                       /*
-                        * Do not complain the most common case
-                        *      git checkout branch
-                        * even if there happen to be a file called 'branch';
-                        * it would be extremely annoying.
-                        */
-                       if (argc)
-                               verify_non_filename(NULL, arg);
-               }
-               else {
-                       argv++;
-                       argc--;
-               }
+               int dwim_ok =
+                       !patch_mode &&
+                       dwim_new_local_branch &&
+                       opts.track == BRANCH_TRACK_UNSPECIFIED &&
+                       !opts.new_branch;
+               int n = parse_branchname_arg(argc, argv, dwim_ok,
+                               &new, &source_tree, rev, &opts.new_branch);
+               argv += n;
+               argc -= n;
        }
 
-no_reference:
-
        if (opts.track == BRANCH_TRACK_UNSPECIFIED)
                opts.track = git_branch_track;
 
@@ -886,6 +1022,9 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                        }
                }
 
+               if (opts.force_detach)
+                       die("git checkout: --detach does not take a path argument");
+
                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.");