Improved submodule merge support

When merging conflicting submodule changes from a supermodule, generate
a conflict message saying what went wrong. Also leave the tree in a state
where git status shows the conflict, and git submodule status gives the user
enough information to do the merge manally. Previously this would just fail.

Signed-off-by: Finn Arne Gangstad <finnag@pvv.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/merge-recursive.c b/merge-recursive.c
index 2a58dad3f43590008045282614fb0f174f3733e5..33ccc40ecd9aadb7fff05ec22b5e94b1567d878d 100644 (file)
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -549,6 +549,10 @@ static void update_file_flags(const unsigned char *sha,
                void *buf;
                unsigned long size;
 
+               if (S_ISGITLINK(mode))
+                       die("cannot read object %s '%s': It is a submodule!",
+                           sha1_to_hex(sha), path);
+
                buf = read_sha1_file(sha, &type, &size);
                if (!buf)
                        die("cannot read object %s '%s'", sha1_to_hex(sha), path);
@@ -1463,10 +1467,13 @@ static int process_entry(const char *path, struct stage_data *entry,
                mfi = merge_file(&o, &a, &b,
                                 branch1, branch2);
 
+               clean_merge = mfi.clean;
                if (mfi.clean)
                        update_file(1, mfi.sha, mfi.mode, path);
+               else if (S_ISGITLINK(mfi.mode))
+                       output(1, "CONFLICT (submodule): Merge conflict in %s "
+                              "- needs %s", path, sha1_to_hex(b.sha1));
                else {
-                       clean_merge = 0;
                        output(1, "CONFLICT (%s): Merge conflict in %s",
                                        reason, path);