push: fix segfault for odd config

If you have a branch.$X.merge config option, but no branch.$X.remote, and
your configuration tries to push tracking branches, git will segfault.

The problem is that even though branch->merge_nr is 1, you don't actually
have an upstream since there is no remote.  Other callsites generally
check explicitly that branch->merge is not NULL, so let's do that here,
too.

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

diff --git a/builtin-push.c b/builtin-push.c
index 45fe843b204274cd59db275c1cce9505231174d3..041e5f46086154c7b879c8bda56ef07553750a78 100644 (file)
--- a/builtin-push.c
+++ b/builtin-push.c
@@ -54,7 +54,7 @@ static void setup_push_tracking(void)
        struct branch *branch = branch_get(NULL);
        if (!branch)
                die("You are not currently on a branch.");
-       if (!branch->merge_nr)
+       if (!branch->merge_nr || !branch->merge)
                die("The current branch %s is not tracking anything.",
                    branch->name);
        if (branch->merge_nr != 1)