tests/test-push-checkheads-unpushed-D6.t

uncommit: leave empty commit if all files are uncommitted

We had instructions for our internal users to add copy information
after commit like this:

  hg uncommit <srcfile> <dstfile>
  hg cp --after <srcfile> <dstfile>
  hg amend

That usually works, but if the rename was the only change in that
commit, then the commit would get pruned. It's easy to fix the recipe:
just pass the --keep option. However, it seems too subtle, so I think
this is an indication that the commit should not be pruned if any
patterns were given.

Differential Revision: https://phab.mercurial-scm.org/D2862

====================================
Testing head checking code: Case D-6
====================================

Mercurial checks for the introduction of new heads on push. Evolution comes
into play to detect if existing branches on the server are being replaced by
some of the new one we push.

This case is part of a series of tests checking this behavior.

Category D: remote head is "obs-affected" locally, but result is not part of the push
TestCase 6: single changeset, superseeded then pruned (on a new changeset unpushed) changeset

This is a partial push variation of case B-6

.. old-state:
..
.. * 1 changeset branch
..
.. new-state:
..
.. * old branch is rewritten onto another one,
.. * the new version is then pruned.
..
.. expected-result:
..
.. * push denied
..
.. graph-summary:
..
..   A ø⇠⊗ A'
..     | |
.. C ◔ | ○ B
..    \|/
..     ●

  $ . $TESTDIR/testlib/push-checkheads-util.sh

Test setup
----------

  $ mkdir D6
  $ cd D6
  $ setuprepos
  creating basic server and client repo
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd client
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkcommit B0
  created new head
  $ mkcommit A1
  $ hg up '0'
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ mkcommit C0
  created new head
  $ hg debugobsolete `getid "desc(A0)"` `getid "desc(A1)"`
  obsoleted 1 changesets
  $ hg debugobsolete --record-parents `getid "desc(A1)"`
  obsoleted 1 changesets
  $ hg log -G --hidden
  @  0f88766e02d6 (draft): C0
  |
  | x  ba93660aff8d (draft): A1
  | |
  | o  74ff5441d343 (draft): B0
  |/
  | x  8aaa48160adc (draft): A0
  |/
  o  1e4be0697311 (public): root
  

Actual testing
--------------

  $ hg push --rev 'desc(C0)'
  pushing to $TESTTMP/D6/server
  searching for changes
  abort: push creates new remote head 0f88766e02d6!
  (merge or see 'hg help push' for details about pushing new heads)
  [255]

  $ cd ../..