tests/test-mq-missingfiles.t

windows: degrade to py2 behavior when reading a non-symlink as a symlink

While waiting for the push to hg-committed in WSL to complete, I ran a
`phabimport` from Windows and got this traceback:

    $ hg phabimport 11313
    ** Unknown exception encountered with possibly-broken third-party extension "mercurial_keyring" (version N/A)
    ** which supports versions unknown of Mercurial.
    ** Please disable "mercurial_keyring" and try your action again.
    ** If that fixes the bug please report it to https://foss.heptapod.net/mercurial/mercurial_keyring/issues
    ** Python 3.9.5 (default, May  6 2021, 17:29:31) [MSC v.1928 64 bit (AMD64)]
    ** Mercurial Distributed SCM (version 5.9rc1+hg32.0e2f5733563d)
    ** Extensions loaded: absorb, blackbox, evolve 10.3.3, extdiff, fastannotate, fix, mercurial_keyring, mq, phabblocker 20210126, phabricator, rebase, show, strip, topic 0.22.3
    Traceback (most recent call last):
      File "mercurial.lock", line 279, in _trylock
      File "mercurial.vfs", line 202, in makelock
      File "mercurial.util", line 2147, in makelock
    FileExistsError: [WinError 183] Cannot create a file when that file already exists: b'hp-omen:78348' -> b'C:\\Users\\Matt\\hg/.hg/store/lock'

    During handling of the above exception, another exception occurred:

    Traceback (most recent call last):
      File "<string>", line 24, in <module>
      File "mercurial.dispatch", line 144, in run
      File "mercurial.dispatch", line 250, in dispatch
      File "mercurial.dispatch", line 294, in _rundispatch
      File "mercurial.dispatch", line 470, in _runcatch
      File "mercurial.dispatch", line 480, in _callcatch
      File "mercurial.scmutil", line 153, in callcatch
      File "mercurial.dispatch", line 460, in _runcatchfunc
      File "mercurial.dispatch", line 1273, in _dispatch
      File "mercurial.dispatch", line 918, in runcommand
      File "mercurial.dispatch", line 1285, in _runcommand
      File "mercurial.dispatch", line 1271, in <lambda>
      File "mercurial.util", line 1886, in check
      File "mercurial.util", line 1886, in check
      File "hgext.mq", line 4239, in mqcommand
      File "mercurial.util", line 1886, in check
      File "mercurial.util", line 1886, in check
      File "hgext.phabricator", line 314, in inner
      File "hgext.phabricator", line 2222, in phabimport
      File "hgext.phabricator", line 2123, in readpatch
      File "hgext.phabricator", line 2199, in _write
      File "mercurial.localrepo", line 2956, in lock
      File "mercurial.localrepo", line 2918, in _lock
      File "mercurial.lock", line 152, in trylock
      File "mercurial.lock", line 283, in _trylock
      File "mercurial.lock", line 314, in _readlock
      File "mercurial.vfs", line 221, in readlock
      File "mercurial.util", line 2163, in readlock
      File "mercurial.windows", line 619, in readlink
    ValueError: not a symbolic link

Both exceptions look accurate (the file exists, and the Windows side can't read
WSL side symlinks).  I didn't try to reproduce this entirely within the Windows
side, but we can do better than a cryptic stacktrace.  With this change, the
same scenario results in this abort:

    abort: C:\Users\Matt\hg/.hg/store/lock: The file cannot be accessed by the system

When both the `push` and `phabimport` are done on the Windows side, it prints a
message about waiting for the lock, and successfully applies the patch after the
push completes.

I'm not sure if there's enough info to be able to convert the abort into the
wait scenario.  As it stands now, we don't support symlinks on Windows, which
requires either a UAC Administrator level process or an opt-in in developer
mode, and there are several places where the new symlink on Windows support in
py3 was explicitly disabled in order to get tests to pass quicker.

Differential Revision: https://phab.mercurial-scm.org/D11333

Issue835: qpush fails immediately when patching a missing file, but
remaining added files are still created empty which will trick a
future qrefresh.

  $ cat > writelines.py <<EOF
  > import sys
  > if sys.version_info[0] >= 3:
  >     encode = lambda x: x.encode('utf-8').decode('unicode_escape').encode('utf-8')
  > else:
  >     encode = lambda x: x.decode('string_escape')
  > path = sys.argv[1]
  > args = sys.argv[2:]
  > assert (len(args) % 2) == 0
  > 
  > f = open(path, 'wb')
  > for i in range(len(args) // 2):
  >    count, s = args[2 * i:2 * i + 2]
  >    count = int(count)
  >    s = encode(s)
  >    f.write(s * count)
  > f.close()
  > EOF

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH

  $ hg init normal
  $ cd normal
  $ "$PYTHON" ../writelines.py b 10 'a\n'
  $ hg ci -Am addb
  adding b
  $ echo a > a
  $ "$PYTHON" ../writelines.py b 2 'b\n' 10 'a\n' 2 'c\n'
  $ echo c > c
  $ hg add a c
  $ hg qnew -f changeb
  $ hg qpop
  popping changeb
  patch queue now empty
  $ hg rm b
  $ hg ci -Am rmb

Push patch with missing target:

  $ hg qpush
  applying changeb
  unable to find 'b' for patching
  (use '--prefix' to apply patch relative to the current directory)
  2 out of 2 hunks FAILED -- saving rejects to file b.rej
  patch failed, unable to continue (try -v)
  patch failed, rejects left in working directory
  errors during apply, please fix and qrefresh changeb
  [2]

Display added files:

  $ cat a
  a
  $ cat c
  c

Display rejections:

  $ cat b.rej
  --- b
  +++ b
  @@ -1,3 +1,5 @@
  +b
  +b
   a
   a
   a
  @@ -8,3 +10,5 @@
   a
   a
   a
  +c
  +c

Test missing renamed file

  $ hg qpop
  popping changeb
  patch queue now empty
  $ hg up -qC 0
  $ echo a > a
  $ hg mv b bb
  $ "$PYTHON" ../writelines.py bb 2 'b\n' 10 'a\n' 2 'c\n'
  $ echo c > c
  $ hg add a c
  $ hg qnew changebb
  $ hg qpop
  popping changebb
  patch queue now empty
  $ hg up -qC 1
  $ hg qpush
  applying changebb
  patching file bb
  Hunk #1 FAILED at 0
  Hunk #2 FAILED at 7
  2 out of 2 hunks FAILED -- saving rejects to file bb.rej
  b not tracked!
  patch failed, unable to continue (try -v)
  patch failed, rejects left in working directory
  errors during apply, please fix and qrefresh changebb
  [2]
  $ cat a
  a
  $ cat c
  c
  $ cat bb.rej
  --- bb
  +++ bb
  @@ -1,3 +1,5 @@
  +b
  +b
   a
   a
   a
  @@ -8,3 +10,5 @@
   a
   a
   a
  +c
  +c

  $ cd ..


  $ echo "[diff]" >> $HGRCPATH
  $ echo "git=1" >> $HGRCPATH

  $ hg init git
  $ cd git
  $ "$PYTHON" ../writelines.py b 1 '\x00'
  $ hg ci -Am addb
  adding b
  $ echo a > a
  $ "$PYTHON" ../writelines.py b 1 '\x01' 1 '\x00'
  $ echo c > c
  $ hg add a c
  $ hg qnew -f changeb
  $ hg qpop
  popping changeb
  patch queue now empty
  $ hg rm b
  $ hg ci -Am rmb

Push git patch with missing target:

  $ hg qpush
  applying changeb
  unable to find 'b' for patching
  (use '--prefix' to apply patch relative to the current directory)
  1 out of 1 hunks FAILED -- saving rejects to file b.rej
  patch failed, unable to continue (try -v)
  patch failed, rejects left in working directory
  errors during apply, please fix and qrefresh changeb
  [2]
  $ hg st
  ? b.rej

Display added files:

  $ cat a
  a
  $ cat c
  c

Display rejections:

  $ cat b.rej
  --- b
  +++ b
  GIT binary patch
  literal 2
  Jc${No0000400IC2
  
  $ cd ..

Test push creating directory during git copy or rename:

  $ hg init missingdir
  $ cd missingdir
  $ echo a > a
  $ hg ci -Am adda
  adding a
  $ mkdir d
  $ hg copy a d/a2
  $ hg mv a d/a
  $ hg qnew -g -f patch
  $ hg qpop
  popping patch
  patch queue now empty
  $ hg qpush
  applying patch
  now at: patch

  $ cd ..