extdiff: drop the command alias without options example in the help text
In the dropped example, the extension would look for 'vdiff.diffargs' in the
configuration, and not finding it, would run kdiff3 without the configured
options. That's not obvious to a new user who sees a kdiff3 configuration in
the prepackaged mergetools.rc file, and sees that kdiff3 still runs. While it
is conceivable that the user wants a kdiff3 command that runs without the
preconfigured options, it is more likely what they want is this, which uses the
canned options:
[alias]
vdiff = kdiff3
[extdiff]
kdiff3 =
We could mention alias here, but that seems like it belongs elswhere.
# This is a randomized test that generates different pathnames every
# time it is invoked, and tests the encoding of those pathnames.
#
# It uses a simple probabilistic model to generate valid pathnames
# that have proven likely to expose bugs and divergent behaviour in
# different encoding implementations.
from mercurial import store
import binascii, itertools, math, os, random, sys, time
import collections
if sys.version_info[:2] < (2, 6):
sys.exit(0)
validchars = set(map(chr, range(0, 256)))
alphanum = range(ord('A'), ord('Z'))
for c in '\0/':
validchars.remove(c)
winreserved = ('aux con prn nul'.split() +
['com%d' % i for i in xrange(1, 10)] +
['lpt%d' % i for i in xrange(1, 10)])
def casecombinations(names):
'''Build all case-diddled combinations of names.'''
combos = set()
for r in names:
for i in xrange(len(r) + 1):
for c in itertools.combinations(xrange(len(r)), i):
d = r
for j in c:
d = ''.join((d[:j], d[j].upper(), d[j + 1:]))
combos.add(d)
return sorted(combos)
def buildprobtable(fp, cmd='hg manifest tip'):
'''Construct and print a table of probabilities for path name
components. The numbers are percentages.'''
counts = collections.defaultdict(lambda: 0)
for line in os.popen(cmd).read().splitlines():
if line[-2:] in ('.i', '.d'):
line = line[:-2]
if line.startswith('data/'):
line = line[5:]
for c in line:
counts[c] += 1
for c in '\r/\n':
counts.pop(c, None)
t = sum(counts.itervalues()) / 100.0
fp.write('probtable = (')
for i, (k, v) in enumerate(sorted(counts.iteritems(), key=lambda x: x[1],
reverse=True)):
if (i % 5) == 0:
fp.write('\n ')
vt = v / t
if vt < 0.0005:
break
fp.write('(%r, %.03f), ' % (k, vt))
fp.write('\n )\n')
# A table of character frequencies (as percentages), gleaned by
# looking at filelog names from a real-world, very large repo.
probtable = (
('t', 9.828), ('e', 9.042), ('s', 8.011), ('a', 6.801), ('i', 6.618),
('g', 5.053), ('r', 5.030), ('o', 4.887), ('p', 4.363), ('n', 4.258),
('l', 3.830), ('h', 3.693), ('_', 3.659), ('.', 3.377), ('m', 3.194),
('u', 2.364), ('d', 2.296), ('c', 2.163), ('b', 1.739), ('f', 1.625),
('6', 0.666), ('j', 0.610), ('y', 0.554), ('x', 0.487), ('w', 0.477),
('k', 0.476), ('v', 0.473), ('3', 0.336), ('1', 0.335), ('2', 0.326),
('4', 0.310), ('5', 0.305), ('9', 0.302), ('8', 0.300), ('7', 0.299),
('q', 0.298), ('0', 0.250), ('z', 0.223), ('-', 0.118), ('C', 0.095),
('T', 0.087), ('F', 0.085), ('B', 0.077), ('S', 0.076), ('P', 0.076),
('L', 0.059), ('A', 0.058), ('N', 0.051), ('D', 0.049), ('M', 0.046),
('E', 0.039), ('I', 0.035), ('R', 0.035), ('G', 0.028), ('U', 0.026),
('W', 0.025), ('O', 0.017), ('V', 0.015), ('H', 0.013), ('Q', 0.011),
('J', 0.007), ('K', 0.005), ('+', 0.004), ('X', 0.003), ('Y', 0.001),
)
for c, _ in probtable:
validchars.remove(c)
validchars = list(validchars)
def pickfrom(rng, table):
c = 0
r = rng.random() * sum(i[1] for i in table)
for i, p in table:
c += p
if c >= r:
return i
reservedcombos = casecombinations(winreserved)
# The first component of a name following a slash.
firsttable = (
(lambda rng: pickfrom(rng, probtable), 90),
(lambda rng: rng.choice(validchars), 5),
(lambda rng: rng.choice(reservedcombos), 5),
)
# Components of a name following the first.
resttable = firsttable[:-1]
# Special suffixes.
internalsuffixcombos = casecombinations('.hg .i .d'.split())
# The last component of a path, before a slash or at the end of a name.
lasttable = resttable + (
(lambda rng: '', 95),
(lambda rng: rng.choice(internalsuffixcombos), 5),
)
def makepart(rng, k):
'''Construct a part of a pathname, without slashes.'''
p = pickfrom(rng, firsttable)(rng)
l = len(p)
ps = [p]
maxl = rng.randint(1, k)
while l < maxl:
p = pickfrom(rng, resttable)(rng)
l += len(p)
ps.append(p)
ps.append(pickfrom(rng, lasttable)(rng))
return ''.join(ps)
def makepath(rng, j, k):
'''Construct a complete pathname.'''
return ('data/' + '/'.join(makepart(rng, k) for _ in xrange(j)) +
rng.choice(['.d', '.i']))
def genpath(rng, count):
'''Generate random pathnames with gradually increasing lengths.'''
mink, maxk = 1, 4096
def steps():
for i in xrange(count):
yield mink + int(round(math.sqrt((maxk - mink) * float(i) / count)))
for k in steps():
x = rng.randint(1, k)
y = rng.randint(1, k)
yield makepath(rng, x, y)
def runtests(rng, seed, count):
nerrs = 0
for p in genpath(rng, count):
h = store._pathencode(p) # uses C implementation, if available
r = store._hybridencode(p, True) # reference implementation in Python
if h != r:
if nerrs == 0:
print >> sys.stderr, 'seed:', hex(seed)[:-1]
print >> sys.stderr, "\np: '%s'" % p.encode("string_escape")
print >> sys.stderr, "h: '%s'" % h.encode("string_escape")
print >> sys.stderr, "r: '%s'" % r.encode("string_escape")
nerrs += 1
return nerrs
def main():
import getopt
# Empirically observed to take about a second to run
count = 100
seed = None
opts, args = getopt.getopt(sys.argv[1:], 'c:s:',
['build', 'count=', 'seed='])
for o, a in opts:
if o in ('-c', '--count'):
count = int(a)
elif o in ('-s', '--seed'):
seed = long(a, base=0) # accepts base 10 or 16 strings
elif o == '--build':
buildprobtable(sys.stdout,
'find .hg/store/data -type f && '
'cat .hg/store/fncache 2>/dev/null')
sys.exit(0)
if seed is None:
try:
seed = long(binascii.hexlify(os.urandom(16)), 16)
except AttributeError:
seed = long(time.time() * 1000)
rng = random.Random(seed)
if runtests(rng, seed, count):
sys.exit(1)
if __name__ == '__main__':
main()