tests/svn-safe-append.py

tests: unset environment variable P in test-revset2.t (issue6109)

The test tests/test-revset2.t fails the test case

"Test repo.anyrevs with customized revset overrides" (line 1609)

if the environment variable P is set. The test implicitly expects that the
environment, in which it is started, does not export the variable 'P'.

To solve this issue, unset 'P' right before the test commands are run.

Differential Revision: https://phab.mercurial-scm.org/D6195

#!/usr/bin/env python

from __future__ import absolute_import

__doc__ = """Same as `echo a >> b`, but ensures a changed mtime of b.
Without this svn will not detect workspace changes."""

import os
import stat
import sys

if sys.version_info[0] >= 3:
    text = os.fsencode(sys.argv[1])
    fname = os.fsencode(sys.argv[2])
else:
    text = sys.argv[1]
    fname = sys.argv[2]

f = open(fname, "ab")
try:
    before = os.fstat(f.fileno())[stat.ST_MTIME]
    f.write(text)
    f.write(b"\n")
finally:
    f.close()
inc = 1
now = os.stat(fname)[stat.ST_MTIME]
while now == before:
    t = now + inc
    inc += 1
    os.utime(fname, (t, t))
    now = os.stat(fname)[stat.ST_MTIME]