refuse to merge during a merge

The following is an easy mistake to make for users coming from version
control systems with an "update and commit"-style workflow.

1. git pull
2. resolve conflicts
3. git pull

Step 3 overrides MERGE_HEAD, starting a new merge with dirty index.
IOW, probably not what the user intended. Instead, refuse to merge
again if a merge is in progress.

Reported-by: Dave Olszewski <cxreg@pobox.com>
Signed-off-by: Clemens Buchacher <drizzd@aon.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin-merge.c b/builtin-merge.c
index 0b58e5eda1f38c1560cc9dcf69be37fa5fc9886f..9e9bd526c39e25b257733a575e8c690ed494f214 100644 (file)
--- a/builtin-merge.c
+++ b/builtin-merge.c
@@ -836,8 +836,11 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
        struct commit_list **remotes = &remoteheads;
 
        setup_work_tree();
+       if (file_exists(git_path("MERGE_HEAD")))
+               die("You have not concluded your merge. (MERGE_HEAD exists)");
        if (read_cache_unmerged())
-               die("You are in the middle of a conflicted merge.");
+               die("You are in the middle of a conflicted merge."
+                               " (index unmerged)");
 
        /*
         * Check if we are _not_ on a detached HEAD, i.e. if there is a

diff --git a/t/t3030-merge-recursive.sh b/t/t3030-merge-recursive.sh
index 0de613dc53d85c01f6d122834e094503a2736507..9b3fa2bdcd9bebae46a000ffe9c2059cea5a93fd 100755 (executable)
--- a/t/t3030-merge-recursive.sh
+++ b/t/t3030-merge-recursive.sh
@@ -276,6 +276,9 @@ test_expect_success 'fail if the index has unresolved entries' '
 
        test_must_fail git merge "$c5" &&
        test_must_fail git merge "$c5" 2> out &&
+       grep "You have not concluded your merge" out &&
+       rm -f .git/MERGE_HEAD &&
+       test_must_fail git merge "$c5" 2> out &&
        grep "You are in the middle of a conflicted merge" out
 
 '