push: introduce REJECT_FETCH_FIRST and REJECT_NEEDS_FORCE
When we push to update an existing ref, if:
* the object at the tip of the remote is not a commit; or
* the object we are pushing is not a commit,
it won't be correct to suggest to fetch, integrate and push again,
as the old and new objects will not "merge". We should explain that
the push must be forced when there is a non-committish object is
involved in such a case.
If we do not have the current object at the tip of the remote, we do
not even know that object, when fetched, is something that can be
merged. In such a case, suggesting to pull first just like
non-fast-forward case may not be technically correct, but in
practice, most such failures are seen when you try to push your work
to a branch without knowing that somebody else already pushed to
update the same branch since you forked, so "pull first" would work
as a suggestion most of the time. And if the object at the tip is
not a commit, "pull first" will fail, without making any permanent
damage. As a side effect, it also makes the error message the user
will get during the next "push" attempt easier to understand, now
the user is aware that a non-commit object is involved.
In these cases, the current code already rejects such a push on the
client end, but we used the same error and advice messages as the
ones used when rejecting a non-fast-forward push, i.e. pull from
there and integrate before pushing again.
Introduce new rejection reasons and reword the messages
appropriately.
[jc: with help by Peff on message details]
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/transport.h b/transport.h
index bfd2df5..c818763 100644
--- a/transport.h
+++ b/transport.h
@@ -143,6 +143,8 @@
#define REJECT_NON_FF_HEAD 0x01
#define REJECT_NON_FF_OTHER 0x02
#define REJECT_ALREADY_EXISTS 0x04
+#define REJECT_FETCH_FIRST 0x08
+#define REJECT_NEEDS_FORCE 0x10
int transport_push(struct transport *connection,
int refspec_nr, const char **refspec, int flags,
