tests/svn-safe-append.py

narrowspec: move module into core

Having support for parsing the narrow specification in core is
necessary for moving many other parts of narrow to core.

We do still want to harmonize the narrow spec with the sparse
spec. And the format needs to be documented. But this shouldn't
hold up the code moving to core.

Differential Revision: https://phab.mercurial-scm.org/D2201

#!/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 sys

text = sys.argv[1]
fname = sys.argv[2]

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