tests/test-push-checkheads-pruned-B5.t

requires: re-use vfs.tryread for simplicity

Avoids calling `set` twice or having to re-raise an exception and implements the routine with a single return expression.

====================================
Testing head checking code: Case B-5
====================================

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 B: simple case involving pruned changesets
TestCase 5: multi-changeset branch, mix of pruned and superseded

.. old-state:
..
.. * 3 changeset branch
..
.. new-state:
..
.. * old head is pruned
.. * old mid is superseded
.. * old root is pruned
..
.. expected-result:
..
.. * push allowed
..
.. graph-summary:
..
..   B ⊗
..     |
..   A ø⇠◔ A'
..     | |
..   B ⊗ |
..     |/
..     ●

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

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

  $ mkdir B5
  $ cd B5
  $ 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
  $ mkcommit C0
  $ cd ../client
  $ hg pull
  pulling from $TESTTMP/B5/server
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files
  new changesets d73caddc5533:821fb21d0dd2 (2 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 B1
  created new head
  $ hg debugobsolete --record-parents `getid "desc(A0)"`
  1 new obsolescence markers
  obsoleted 1 changesets
  2 new orphan changesets
  $ hg debugobsolete `getid "desc(B0)"` `getid "desc(B1)"`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg debugobsolete --record-parents `getid "desc(C0)"`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg log -G --hidden
  @  25c56d33e4c4 (draft): B1
  |
  | x  821fb21d0dd2 (draft): C0
  | |
  | x  d73caddc5533 (draft): B0
  | |
  | x  8aaa48160adc (draft): A0
  |/
  o  1e4be0697311 (public): root
  

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

  $ hg push
  pushing to $TESTTMP/B5/server
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  3 new obsolescence markers
  obsoleted 3 changesets

  $ cd ../..