merge: indicate remote tracking branches in merge message

Previously when merging directly from a local tracking
branch like:

  git merge origin/master

The merge message said:

   Merge commit 'origin/master'

     * commit 'origin/master':
       ...

Instead, let's be more explicit about what we are merging:

   Merge remote branch 'origin/master'

     * origin/master:
       ...

We accomplish this by recognizing remote tracking branches
in git-merge when we build the simulated FETCH_HEAD output
that we feed to fmt-merge-msg.

In addition to a new test in t7608, we have to tweak the
expected output of t3409, which does such a merge.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/t/t7608-merge-messages.sh b/t/t7608-merge-messages.sh
index 81ced8ac3c..28d56797b1 100755
--- a/t/t7608-merge-messages.sh
+++ b/t/t7608-merge-messages.sh
@@ -47,4 +47,14 @@ test_expect_success 'ambiguous tag' '
 	check_oneline "Merge commit QambiguousQ"
 '
 
+test_expect_success 'remote branch' '
+	git checkout -b remote master &&
+	test_commit remote-1 &&
+	git update-ref refs/remotes/origin/master remote &&
+	git checkout master &&
+	test_commit master-5 &&
+	git merge origin/master &&
+	check_oneline "Merge remote branch Qorigin/masterQ"
+'
+
 test_done