tests/test-merge-halt.t

py3: allow run-tests.py to run on Windows

This is now functional:

    HGMODULEPOLICY=py py -3 run-tests.py --local test-help.t --pure --view bcompare

However, on this machine without a C compiler, it tries to load cext anyway, and
blows up.  I haven't looked into why, other than to see that it does set the
environment variable.  When the test exits though, I see it can't find
killdaemons.py, get-with-headers.py, etc.

I have no idea why these changes are needed, given that it runs on Linux.  But
os.system() is insisting that it take a str, and subprocess.Popen() blows up
without str:

    Errored test-help.t: Traceback (most recent call last):
      File "run-tests.py", line 810, in run
        self.runTest()
      File "run-tests.py", line 858, in runTest
        ret, out = self._run(env)
      File "run-tests.py", line 1268, in _run
        exitcode, output = self._runcommand(cmd, env)
      File "run-tests.py", line 1141, in _runcommand
        env=env)
      File "C:\Program Files\Python37\lib\subprocess.py", line 756, in __init__
        restore_signals, start_new_session)
      File "C:\Program Files\Python37\lib\subprocess.py", line 1100, in _execute_child
        args = list2cmdline(args)
      File "C:\Program Files\Python37\lib\subprocess.py", line 511, in list2cmdline
        needquote = (" " in arg) or ("\t" in arg) or not arg
    TypeError: argument of type 'int' is not iterable

This is exactly how it crashes when trying to spin up a pager too.  I left one
instance of os.system() unchanged in _installhg(), because it doesn't get there.

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > rebase=
  > [phases]
  > publish=False
  > [merge]
  > EOF

  $ hg init repo
  $ cd repo
  $ echo a > a
  $ echo b > b
  $ hg commit -qAm ab
  $ echo c >> a
  $ echo c >> b
  $ hg commit -qAm c
  $ hg up -q ".^"
  $ echo d >> a
  $ echo d >> b
  $ hg commit -qAm d

Testing on-failure=continue
  $ echo on-failure=continue >> $HGRCPATH
  $ hg rebase -s 1 -d 2 --tool false
  rebasing 1:1f28a51c3c9b "c"
  merging a
  merging b
  merging a failed!
  merging b failed!
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]

  $ hg resolve --list
  U a
  U b

  $ hg rebase --abort
  rebase aborted

Testing on-failure=halt
  $ echo on-failure=halt >> $HGRCPATH
  $ hg rebase -s 1 -d 2 --tool false
  rebasing 1:1f28a51c3c9b "c"
  merging a
  merging b
  merging a failed!
  merge halted after failed merge (see hg resolve)
  [1]

  $ hg resolve --list
  U a
  U b

  $ hg rebase --abort
  rebase aborted

Testing on-failure=prompt
  $ cat <<EOS >> $HGRCPATH
  > [merge]
  > on-failure=prompt
  > [ui]
  > interactive=1
  > EOS
  $ cat <<EOS | hg rebase -s 1 -d 2 --tool false
  > y
  > n
  > EOS
  rebasing 1:1f28a51c3c9b "c"
  merging a
  merging b
  merging a failed!
  continue merge operation (yn)? y
  merging b failed!
  continue merge operation (yn)? n
  merge halted after failed merge (see hg resolve)
  [1]

  $ hg resolve --list
  U a
  U b

  $ hg rebase --abort
  rebase aborted

Check that successful tool with failed post-check halts the merge
  $ cat <<EOS >> $HGRCPATH
  > [merge-tools]
  > true.check=changed
  > EOS
  $ cat <<EOS | hg rebase -s 1 -d 2 --tool true
  > y
  > n
  > n
  > EOS
  rebasing 1:1f28a51c3c9b "c"
  merging a
  merging b
   output file a appears unchanged
  was merge successful (yn)? y
   output file b appears unchanged
  was merge successful (yn)? n
  merging b failed!
  continue merge operation (yn)? n
  merge halted after failed merge (see hg resolve)
  [1]

  $ hg resolve --list
  R a
  U b

  $ hg rebase --abort
  rebase aborted

Check that conflicts with conflict check also halts the merge
  $ cat <<EOS >> $HGRCPATH
  > [merge-tools]
  > true.check=conflicts
  > true.premerge=keep
  > [merge]
  > on-failure=halt
  > EOS
  $ hg rebase -s 1 -d 2 --tool true
  rebasing 1:1f28a51c3c9b "c"
  merging a
  merging b
  merging a failed!
  merge halted after failed merge (see hg resolve)
  [1]

  $ hg resolve --list
  U a
  U b

  $ hg rebase --abort
  rebase aborted

Check that always-prompt also can halt the merge
  $ cat <<EOS | hg rebase -s 1 -d 2 --tool true --config merge-tools.true.check=prompt
  > y
  > n
  > EOS
  rebasing 1:1f28a51c3c9b "c"
  merging a
  merging b
  was merge of 'a' successful (yn)? y
  was merge of 'b' successful (yn)? n
  merging b failed!
  merge halted after failed merge (see hg resolve)
  [1]

  $ hg resolve --list
  R a
  U b

  $ hg rebase --abort
  rebase aborted

Check that successful tool otherwise allows the merge to continue
  $ hg rebase -s 1 -d 2 --tool echo --keep --config merge-tools.echo.premerge=keep
  rebasing 1:1f28a51c3c9b "c"
  merging a
  merging b
  $TESTTMP/repo/a *a~base* *a~other* (glob)
  $TESTTMP/repo/b *b~base* *b~other* (glob)