rhg: Add support for `rhg status --copies`
Copy sources are collected during `status()` rather than after the fact like
in Python, because `status()` takes a `&mut` exclusive reference to the dirstate map
(in order to potentially mutate it for directory mtimes) and returns `Cow<'_, HgPath>`
that borrow the dirstate map.
Even though with `Cow` only some shared borrows remain, the still extend the same
lifetime of the initial `&mut` so the dirstate map cannot be borrowed again
to access copy sources after the fact:
https://doc.rust-lang.org/nomicon/lifetime-mismatch.html#limits-of-lifetimes
Additionally, collecting copy sources during the dirstate tree traversal that
`status()` already does avoids the cost of another traversal or other lookups
(though I haven’t benchmarked that cost).
Differential Revision: https://phab.mercurial-scm.org/D11899
#!/usr/bin/env python3
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]