mailmap: default mailmap.blob in bare repositories

The motivation for mailmap.blob is to let users of bare
repositories use the mailmap feature, as they would not have
a checkout containing the .mailmap file. We can make it even
easier for them by just looking in HEAD:.mailmap by default.

We can't know for sure that this is where they would keep a
mailmap, of course, but it is the best guess (and it matches
the non-bare behavior, which reads from HEAD:.mailmap in the
working tree). If it's missing, git will silently ignore the
setting.

We do not do the same magic in the non-bare case, because:

  1. In the common case, HEAD:.mailmap will be the same as
     the .mailmap in the working tree, which is a no-op.

  2. In the uncommon case, the user has modified .mailmap
     but not yet committed it, and would expect the working
     tree version to take precedence.

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

1 files changed, 5 insertions, 0 deletions

diff --git a/mailmap.c b/mailmap.c
index 5ffe48a604..b16542febe 100644
--- a/mailmap.c
+++ b/mailmap.c
@@ -233,7 +233,12 @@ static int read_mailmap_blob(struct string_list *map,
 int read_mailmap(struct string_list *map, char **repo_abbrev)
 {
 	int err = 0;
+
 	map->strdup_strings = 1;
+
+	if (!git_mailmap_blob && is_bare_repository())
+		git_mailmap_blob = "HEAD:.mailmap";
+
 	err |= read_mailmap_file(map, ".mailmap", repo_abbrev);
 	err |= read_mailmap_blob(map, git_mailmap_blob, repo_abbrev);
 	err |= read_mailmap_file(map, git_mailmap_file, repo_abbrev);