tests/svn-safe-append.py

shelve: move possible shelve file extensions to a single place

This and a couple of following patches are a preparation to
implementing obsolescense-enabled shelve which was discussed
on a Sprint. If this refactoring is not done, shelve is going
to look even more hackish than now.

This particular commit introduces a slight behavior change. Previously,
if only .hg/shelve/name.patch file exists, but .hg/name.hg does not,
'hg shelve -d name' would fail saying "shelve not found". Now deletion
will only fail if .patch file does not exist (since .patch is used
as an indicator of an existing shelve). Other shelve files being absent
are skipped silently to accommodate for future introduction of obs-based
shelve, which will mean that for some shelves .hg and .patch files exist,
while for others .hg and .oshelve.

#!/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