[PATCH v4 0/3] Finishing touches to "push" advises

This builds on Chris Rorvick's earlier effort to forbid unforced updates to refs/tags/ hierarchy and giving sensible error and advise messages for that case (we are not rejecting such a push due to fast forwardness, and suggesting to fetch and integrate before pushing again does not make sense).

The series applies on top of 256b9d7 (push: fix "refs/tags/ hierarchy cannot be updated without --force", 2013-01-16).

This fourth round swaps the order of clean-up patches and now the bottom two are clean-up patches. The main change is in the third one.

When the object at the tip of the remote is not a committish, or the object we are pushing is not a committish, the existing 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 push that does not fast-forward, i.e. pull from there and integrate before pushing again. Introduce a new rejection reason NEEDS_FORCE and explain why the push was rejected, stressing the fact that --force is required when non committish objects are involved, so that the user can (1) notice a possibly mistyped source object name or destination ref name, when the user is trying to push an ordinary commit, or (2) learn that "--force" is an appropriate thing to use when the user is sure that s/he wants to push a non-committish (which is unusual).

Unlike the third round, we do not say "fetch first, inspect the situation to decide what to do", when we do not have the object sitting at the tip of the remote. Most likely, it is a commit somebody who has been working on the same branch pushed that we haven't fetched yet, so suggesting to pull is often sufficient and appropriate, and in a more uncommon case in which the unknown object is not a committish, the suggested pull will fail without making permanent damage anywhere. Next atttempt to push without changing anything (e.g. "reset --hard") will then trigger the NEEDS_FORCE "Your push involves non-commit objects" case.

Junio C Hamano (3):
  push: further clean up fields of "struct ref"
  push: further simplify the logic to assign rejection reason
  push: introduce REJECT_FETCH_FIRST and REJECT_NEEDS_FORCE

 Documentation/config.txt | 12 +++++++++++-
 advice.c                 |  4 ++++
 advice.h                 |  2 ++
 builtin/push.c           | 29 +++++++++++++++++++++++++++++
 builtin/send-pack.c      | 10 ++++++++++
 cache.h                  |  6 +++---
 remote.c                 | 42 +++++++++++++++++++-----------------------
 send-pack.c              |  2 ++
 transport-helper.c       | 10 ++++++++++
 transport.c              | 14 +++++++++++++-
 transport.h              |  2 ++
 11 files changed, 105 insertions(+), 28 deletions(-)