[PATCH 4/6] mailmap: do not resolve blobs in a non-repository

[Jeff King <peff@peff.net>]

The mailmap code may be triggered outside of a repository by
git-shortlog. There is no point in looking up a name like
"HEAD:.mailmap" there; without a repository, we have no
refs.

This is unlikely to matter much in practice for the current
code, as we would simply fail to find the ref. But as the
refs code learns about new backends, this is more important;
without a repository, we do not even know which backend to
look at.

Signed-off-by: Jeff King <peff@peff.net>
---
I debated whether ".mailmap" in the $PWD should be respected in a
non-repository. If it were 2005, I think I could go either way. But it's
not, and changing it now seems like a pointless and unnecessary
regression, even if there is some grounds to argue for it.

 mailmap.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mailmap.c b/mailmap.c
index f4a0f1c..9726237 100644
--- a/mailmap.c
+++ b/mailmap.c
@@ -250,7 +250,8 @@ int read_mailmap(struct string_list *map, char **repo_abbrev)
 		git_mailmap_blob = "HEAD:.mailmap";
 
 	err |= read_mailmap_file(map, ".mailmap", repo_abbrev);
-	err |= read_mailmap_blob(map, git_mailmap_blob, repo_abbrev);
+	if (startup_info->have_repository)
+		err |= read_mailmap_blob(map, git_mailmap_blob, repo_abbrev);
 	err |= read_mailmap_file(map, git_mailmap_file, repo_abbrev);
 	return err;
 }
-- 
2.8.0.rc1.318.g2193183