tests/test-push-checkheads-superceed-A2.t

rebase: also include commit of collapsed commits in single transaction

When rebase.singletransaction is set, we still used to create a second
transaction when committing with --collapse. It's simpler to create a
single transaction.

Note that in the affected .t file, the test that uses --collapse still
appears to create two transactions (it prints "rebase status stored"
twice). However, only a single transaction is actually created and the
second printout comes from cmdutil.commitforceeditor() that explicitly
calls tr.writepending().

Also note the that we now roll back any commits if the user closes the
commit message editor with an error code (or leaves the message
empty). That might be unfortunate, but it's consistent with how we
behave in the --no-collapse case (if the user passed --edit). If we
want to change that, I think it should be done consistently in a
separate patch.

Differential Revision: https://phab.mercurial-scm.org/D2728

====================================
Testing head checking code: Case A-2
====================================

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 A: simple case involving a branch being superceeded by another.
TestCase 2: multi-changeset branch

.. old-state:
..
.. * 1 branch with 2 changesets
..
.. new-state:
..
.. * another 2-changeset branch succeeding the old one
..
.. expected-result:
..
.. * push allowed
..
.. graph-summary:
..
..   B ø⇠◔ B'
..     | |
..   A ø⇠◔ A'
..     |/
..     ●

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

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

  $ mkdir A2
  $ cd A2
  $ 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/A2/server
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets d73caddc5533
  (run 'hg update' to get a working copy)
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkcommit A1
  created new head
  $ mkcommit B1
  $ hg debugobsolete `getid "desc(A0)" ` `getid "desc(A1)"`
  obsoleted 1 changesets
  1 new orphan changesets
  $ hg debugobsolete `getid "desc(B0)" ` `getid "desc(B1)"`
  obsoleted 1 changesets
  $ hg log -G --hidden
  @  262c8c798096 (draft): B1
  |
  o  f6082bc4ffef (draft): A1
  |
  | x  d73caddc5533 (draft): B0
  | |
  | x  8aaa48160adc (draft): A0
  |/
  o  1e4be0697311 (public): root
  

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

  $ hg push
  pushing to $TESTTMP/A2/server
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files (+1 heads)
  2 new obsolescence markers
  obsoleted 2 changesets

  $ cd ../..