tests/svn-safe-append.py

merge: before cd/dc prompt, check that changed side really changed

Before, merging would in some cases ask "wrong" questions about
"changed/deleted" conflicts ... and even do it before the resolve phase where
they can be postponed, re"resolved" or answered in bulk operations.

Instead, check that the content of the changed file really did change.

Reading and comparing file content is expensive and should be avoided before
the resolve phase. Prompting the user is however even more expensive. Checking
the content here is thus better.

The 'f in ancestors[0]' should not be necessary but is included to be extra
safe.

#!/usr/bin/env python

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

import sys, os

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