Mercurial > hg
view contrib/bdiff-torture.py @ 29012:4bd67ae7d75a stable
bdiff: fix latent normalization bug
This bug is hidden by the current bias towards matches at the
beginning of the file. When this bias is tweaked later to address
recursion balancing, the normalization code could cause the next block
to shrink to a negative length, thus creating invalid delta chunks. We
add checks here to disallow that.
This bug requires test cases that are an awkwardly large size for the test
suite, but is very rapidly picked up by the included torture tester.
author | Matt Mackall <mpm@selenic.com> |
---|---|
date | Thu, 21 Apr 2016 21:53:18 -0500 |
parents | |
children | eccfd6500636 |
line wrap: on
line source
# Randomized torture test generation for bdiff from __future__ import absolute_import, print_function import random, sys from mercurial import ( bdiff, mpatch, ) def reducetest(a, b): tries = 0 reductions = 0 print("reducing...") while tries < 1000: a2 = "\n".join(l for l in a.splitlines() if random.randint(0, 100) > 0) + "\n" b2 = "\n".join(l for l in b.splitlines() if random.randint(0, 100) > 0) + "\n" if a2 == a and b2 == b: continue if a2 == b2: continue tries += 1 try: test1(a, b) except Exception as inst: reductions += 1 tries = 0 a = a2 b = b2 print("reduced:", reductions, len(a) + len(b), repr(a), repr(b)) try: test1(a, b) except Exception as inst: print("failed:", inst) sys.exit(0) def test1(a, b): d = bdiff.bdiff(a, b) if not d: raise ValueError("empty") c = mpatch.patches(a, [d]) if c != b: raise ValueError("bad") def testwrap(a, b): try: test1(a, b) return except Exception as inst: pass print("exception:", inst) reducetest(a, b) def test(a, b): testwrap(a, b) testwrap(b, a) def rndtest(size, noise): a = [] src = " aaaaaaaabbbbccd" for x in xrange(size): a.append(src[random.randint(0, len(src) - 1)]) while True: b = [c for c in a if random.randint(0, 99) > noise] b2 = [] for c in b: b2.append(c) while random.randint(0, 99) < noise: b2.append(src[random.randint(0, len(src) - 1)]) if b2 != a: break a = "\n".join(a) + "\n" b = "\n".join(b2) + "\n" test(a, b) maxvol = 10000 startsize = 2 while True: size = startsize count = 0 while size < maxvol: print(size) volume = 0 while volume < maxvol: rndtest(size, 2) volume += size count += 2 size *= 2 maxvol *= 4 startsize *= 4