templates: add filter to reverse list
The filter supports only lists because for lists, it’s straightforward to
implement. Reversing text doesn’t seem very useful and is hard to implement.
Reversing the bytes would break multi-bytes encodings. Reversing the code
points would break characters consisting of multiple code points. Reversing
graphemes is non-trivial without using a library not included in the standard
library.
# Randomized torture test generation for bdiff
import random
import sys
from mercurial import (
mdiff,
pycompat,
)
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:
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 = mdiff.textdiff(a, b)
if not d:
raise ValueError("empty")
c = mdiff.patches(a, [d])
if c != b:
raise ValueError("bad")
def testwrap(a, b):
try:
test1(a, b)
return
except Exception as inst:
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 pycompat.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