tests/test-symlink-placeholder.t

py3: partially fix pager spawning on Windows

Previously, spinning up the pager crashed because the command and environment
was in bytes.  (See also 543a788eea2d.)  Now it aborts with an invalid handle:

    $ HGMODULEPOLICY=py py -3 ../hg --traceback --config extensions.evolve=!
    Traceback (most recent call last):
    File "c:\Users\Matt\projects\hg\mercurial\ui.py", line 967, in _write
      self.fout.write(''.join(msgs))
    File "c:\Users\Matt\projects\hg\mercurial\windows.py", line 173, in write
      self.fp.write(s[start:end])
    OSError: [WinError 6] The handle is invalid

    During handling of the above exception, another exception occurred:

    Traceback (most recent call last):
      File "c:\Users\Matt\projects\hg\mercurial\scmutil.py", line 164, in callcatch
        return func()
      File "c:\Users\Matt\projects\hg\mercurial\dispatch.py", line 350, in _runcatchfunc
        return _dispatch(req)
      File "c:\Users\Matt\projects\hg\mercurial\dispatch.py", line 930, in _dispatch
        return commands.help_(ui, 'shortlist')
      File "c:\Users\Matt\projects\hg\mercurial\commands.py", line 2930, in help_
        ui.write(formatted)
      File "c:\Users\Matt\projects\hg\mercurial\ui.py", line 948, in write
        self._writenobuf(*args, **opts)
      File "c:\Users\Matt\projects\hg\mercurial\ui.py", line 960, in _writenobuf
        self._write(*msgs, **opts)
      File "c:\Users\Matt\projects\hg\mercurial\ui.py", line 969, in _write
        raise error.StdioError(err)
    mercurial.error.StdioError: [Errno 9] The handle is invalid
    abort: The handle is invalid

The interesting bit here is that the abort message is marked with ANSI color,
but the OSError is not.

#require symlink

Create extension that can disable symlink support:

  $ cat > nolink.py <<EOF
  > from mercurial import extensions, util
  > def setflags(orig, f, l, x):
  >     pass
  > def checklink(orig, path):
  >     return False
  > def extsetup(ui):
  >     extensions.wrapfunction(util, 'setflags', setflags)
  >     extensions.wrapfunction(util, 'checklink', checklink)
  > EOF

  $ hg init unix-repo
  $ cd unix-repo
  $ echo foo > a
  $ ln -s a b
  $ hg ci -Am0
  adding a
  adding b
  $ cd ..

Simulate a checkout shared on NFS/Samba:

  $ hg clone -q unix-repo shared
  $ cd shared
  $ rm b
  $ echo foo > b
  $ hg --config extensions.n=$TESTTMP/nolink.py status --debug
  ignoring suspect symlink placeholder "b"

Make a clone using placeholders:

  $ hg --config extensions.n=$TESTTMP/nolink.py clone . ../win-repo
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd ../win-repo
  $ cat b
  a (no-eol)
  $ hg --config extensions.n=$TESTTMP/nolink.py st --debug

Empty placeholder:

  $ rm b
  $ touch b
  $ hg --config extensions.n=$TESTTMP/nolink.py st --debug
  ignoring suspect symlink placeholder "b"

Write binary data to the placeholder:

  >>> open('b', 'w').write('this is a binary\0') and None
  $ hg --config extensions.n=$TESTTMP/nolink.py st --debug
  ignoring suspect symlink placeholder "b"

Write a long string to the placeholder:

  >>> open('b', 'w').write('this' * 1000) and None
  $ hg --config extensions.n=$TESTTMP/nolink.py st --debug
  ignoring suspect symlink placeholder "b"

Commit shouldn't succeed:

  $ hg --config extensions.n=$TESTTMP/nolink.py ci -m1
  nothing changed
  [1]

Write a valid string to the placeholder:

  >>> open('b', 'w').write('this') and None
  $ hg --config extensions.n=$TESTTMP/nolink.py st --debug
  M b
  $ hg --config extensions.n=$TESTTMP/nolink.py ci -m1
  $ hg manifest tip --verbose
  644   a
  644 @ b

  $ cd ..