Merge branch 'maint'

diff --git a/builtin-checkout.c b/builtin-checkout.c
index 8e77767b49888aa2131088a810850dab7854594d..4497b7092d0e88aa731c64c0f22bf0d05ead0411 100644 (file)
--- a/builtin-checkout.c
+++ b/builtin-checkout.c
@@ -184,7 +184,7 @@ struct checkout_opts {
        int force;
        int writeout_error;
 
-       char *new_branch;
+       const char *new_branch;
        int new_branch_log;
        enum branch_track track;
 };
@@ -269,6 +269,8 @@ 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;
@@ -462,13 +464,28 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 
        git_config(git_default_config, NULL);
 
-       opts.track = git_branch_track;
+       opts.track = BRANCH_TRACK_UNSPECIFIED;
 
        argc = parse_options(argc, argv, options, checkout_usage,
                             PARSE_OPT_KEEP_DASHDASH);
 
-       if (!opts.new_branch && (opts.track != git_branch_track))
-               die("git checkout: --track and --no-track require -b");
+       /* --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 (opts.force && opts.merge)
                die("git checkout: -f and -m are incompatible");
@@ -563,6 +580,18 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                return checkout_paths(source_tree, pathspec);
        }
 
+       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.");
        }