tests/test-push-checkheads-partial-C4.t

revlog: have an explicit "pack_header" method

Having to pass the version header when retrieving the binary version of every
single entry is a bit silly. So we extract that special logic in its own method.
This also prepare the move to newer revlog format, not storing the header within
an actual entry…

Differential Revision: https://phab.mercurial-scm.org/D10510

====================================
Testing head checking code: Case C-4
====================================

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 C: case were the branch is only partially obsoleted
TestCase 4: 2 changeset branch, only the base is pruned

.. old-state:
..
.. * 2 changeset branch
..
.. new-state:
..
.. * old base is pruned
.. * 1 new unrelated branch
..
.. expected-result:
..
.. * push denied
..
.. graph-summary:
..
..   B ◔
..     |
..   A ⊗ ◔ C
..     |/
..     ●

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

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

  $ mkdir C4
  $ cd C4
  $ setuprepos
  creating basic server and client repo
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd server
  $ mkcommit B0
  $ cd ../client
  $ hg pull
  pulling from $TESTTMP/C4/server
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets d73caddc5533 (1 drafts)
  (run 'hg update' to get a working copy)
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkcommit C0
  created new head
  $ hg debugobsolete --record-parents `getid "desc(A0)"`
  1 new obsolescence markers
  obsoleted 1 changesets
  1 new orphan changesets
  $ hg log -G --hidden
  @  0f88766e02d6 (draft): C0
  |
  | *  d73caddc5533 (draft): B0
  | |
  | x  8aaa48160adc (draft): A0
  |/
  o  1e4be0697311 (public): root
  

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

  $ hg push --rev 'desc(C0)'
  pushing to $TESTTMP/C4/server
  searching for changes
  abort: push creates new remote head 0f88766e02d6
  (merge or see 'hg help push' for details about pushing new heads)
  [20]

  $ cd ../..