branch: give advice when tracking start-point is missing

If the user requests to --set-upstream-to a branch that does
not exist, then either:

  1. It was a typo.

  2. They thought the branch should exist.

In case (1), there is not much we can do beyond showing the
name we tried to use. For case (2), though, we can help to
guide them through common workflows.

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

1 files changed, 1 insertions, 0 deletions

diff --git a/advice.h b/advice.h
index af0c983c68..94caa32f92 100644
--- a/advice.h
+++ b/advice.h
@@ -16,6 +16,7 @@ extern int advice_commit_before_merge;
 extern int advice_resolve_conflict;
 extern int advice_implicit_identity;
 extern int advice_detached_head;
+extern int advice_set_upstream_failure;
 
 int git_default_advice_config(const char *var, const char *value);
 void advise(const char *advice, ...);