view tests/svn-safe-append.py @ 23100:ac494b087feb stable

revset: fix O(2^n) perf regression in addset hg log -r 1 ... -r 100 was never returning due to a regression in the way addset computes __nonzero__. It used 'bool(self._r1 or self._r2)' which required executing self._r1.__nonzero__ twice (once for the or, once for the bool). hg log with a lot of -r's happens to build a one sided addset tree of N length, which ends up being 2^N performance. This patch fixes it by converting to bool before or'ing. This problem can be repro'd with something as simple as: hg log `for x in $(seq 1 50) ; do echo "-r $x "; done` Adding '1 + 2 + ... + 20' to the revsetbenchmark.txt didn't seem to repro the problem, so I wasn't able to add a revset benchmark for this issue.
author Durham Goode <durham@fb.com>
date Tue, 28 Oct 2014 14:06:06 -0700
parents c1b47c0fd2b6
children bdba6a2015d0
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#!/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