branch: do not attempt to track HEAD implicitly

With branch.autosetupmerge=always, 'HEAD' becomes a valid target for
branch tracking.  This is a bit silly, and in fact the code already
guards against it when attempting it explicitly:

  $ git checkout HEAD^0
  $ git branch -t foo
  fatal: Cannot setup tracking information; starting point is not a branch.

Silently drop the HEAD candidate in the implicit (i.e. without -t
flag) case, so that the branch starts out without an upstream.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/branch.c b/branch.c
index 93dc866f8c09a2da2308c4fd677178b043f2d4d5..19310e4e88cf8276b418b7f20c95e1faa97f6020 100644 (file)
--- a/branch.c
+++ b/branch.c
@@ -176,8 +176,12 @@ void create_branch(const char *head,
                break;
        case 1:
                /* Unique completion -- good, only if it is a real ref */
-               if (explicit_tracking && !strcmp(real_ref, "HEAD"))
-                       die("Cannot setup tracking information; starting point is not a branch.");
+               if (!strcmp(real_ref, "HEAD")) {
+                       if (explicit_tracking)
+                               die("Cannot setup tracking information; starting point is not a branch.");
+                       else
+                               real_ref = NULL;
+               }
                break;
        default:
                die("Ambiguous object name: '%s'.", start_name);

diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index f54a533456d74a3eb2f745dbc77c8ad5a5ae960f..dce90de74d10af16c3df2d90ad4419b5ee6fd7dd 100755 (executable)
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -477,6 +477,15 @@ test_expect_success 'autosetuprebase always on an untracked remote branch' '
        test "z$(git config branch.myr20.rebase)" = z
 '
 
+test_expect_success 'autosetuprebase always on detached HEAD' '
+       git config branch.autosetupmerge always &&
+       test_when_finished git checkout master &&
+       git checkout HEAD^0 &&
+       git branch my11 &&
+       test -z "$(git config branch.my11.remote)" &&
+       test -z "$(git config branch.my11.merge)"
+'
+
 test_expect_success 'detect misconfigured autosetuprebase (bad value)' '
        git config branch.autosetuprebase garbage &&
        test_must_fail git branch