branch -m: allow renaming a yet-unborn branch

In one of the next commits, we would like to give users some advice
regarding the initial branch name, and how to modify it.

To that end, it would be good if `git branch -m <name>` worked in a
freshly initialized repository without any commits. Let's make it so.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/branch.c b/builtin/branch.c
index efb30b882069446e82b69256d6b768c4c795608e..200da319f1dffdd6b1f5321a5530ad6c4cc60128 100644 (file)
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -538,7 +538,9 @@ static void copy_or_rename_branch(const char *oldname, const char *newname, int
                strbuf_addf(&logmsg, "Branch: renamed %s to %s",
                            oldref.buf, newref.buf);
 
-       if (!copy && rename_ref(oldref.buf, newref.buf, logmsg.buf))
+       if (!copy &&
+           (!head || strcmp(oldname, head) || !is_null_oid(&head_oid)) &&
+           rename_ref(oldref.buf, newref.buf, logmsg.buf))
                die(_("Branch rename failed"));
        if (copy && copy_existing_ref(oldref.buf, newref.buf, logmsg.buf))
                die(_("Branch copy failed"));

diff --git a/t/t0001-init.sh b/t/t0001-init.sh
index 69a320489fca1f0df400e289cde6c1d250efe066..bb23e56a1659e2dede5c67a545b371c8178c1cb4 100755 (executable)
--- a/t/t0001-init.sh
+++ b/t/t0001-init.sh
@@ -571,4 +571,12 @@ test_expect_success 'invalid default branch name' '
        test_i18ngrep "invalid branch name" err
 '
 
+test_expect_success 'branch -m with the initial branch' '
+       git init rename-initial &&
+       git -C rename-initial branch -m renamed &&
+       test renamed = $(git -C rename-initial symbolic-ref --short HEAD) &&
+       git -C rename-initial branch -m renamed again &&
+       test again = $(git -C rename-initial symbolic-ref --short HEAD)
+'
+
 test_done