view tests/test-pathencode.py @ 46393:66e8e279133b

hghave: list the module needed for the `vcr` check

I'm tired of having to look up modules each time I setup a system, and try to
distinguish between similar package names to get the right one.  Now that the
search API has been disabled, it's even harder.  There are other python packages
here that should be listed like this, but this is the one that came up missing
today, so it's a start.

Differential Revision: https://phab.mercurial-scm.org/D9879

# 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 behavior in
# different encoding implementations.

from __future__ import absolute_import, print_function

import binascii
import collections
import itertools
import math
import os
import random
import sys
import time
from mercurial import (
    pycompat,
    store,
)

try:
    xrange
except NameError:
    xrange = range

validchars = set(map(pycompat.bytechr, range(0, 256)))
alphanum = range(ord('A'), ord('Z'))

for c in (b'\0', b'/'):
    validchars.remove(c)

winreserved = (
    b'aux con prn nul'.split()
    + [b'com%d' % i for i in xrange(1, 10)]
    + [b'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 = b''.join((d[:j], d[j : j + 1].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(pycompat.itervalues(counts)) / 100.0
    fp.write('probtable = (')
    for i, (k, v) in enumerate(
        sorted(counts.items(), 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 = (
    (b't', 9.828),
    (b'e', 9.042),
    (b's', 8.011),
    (b'a', 6.801),
    (b'i', 6.618),
    (b'g', 5.053),
    (b'r', 5.030),
    (b'o', 4.887),
    (b'p', 4.363),
    (b'n', 4.258),
    (b'l', 3.830),
    (b'h', 3.693),
    (b'_', 3.659),
    (b'.', 3.377),
    (b'm', 3.194),
    (b'u', 2.364),
    (b'd', 2.296),
    (b'c', 2.163),
    (b'b', 1.739),
    (b'f', 1.625),
    (b'6', 0.666),
    (b'j', 0.610),
    (b'y', 0.554),
    (b'x', 0.487),
    (b'w', 0.477),
    (b'k', 0.476),
    (b'v', 0.473),
    (b'3', 0.336),
    (b'1', 0.335),
    (b'2', 0.326),
    (b'4', 0.310),
    (b'5', 0.305),
    (b'9', 0.302),
    (b'8', 0.300),
    (b'7', 0.299),
    (b'q', 0.298),
    (b'0', 0.250),
    (b'z', 0.223),
    (b'-', 0.118),
    (b'C', 0.095),
    (b'T', 0.087),
    (b'F', 0.085),
    (b'B', 0.077),
    (b'S', 0.076),
    (b'P', 0.076),
    (b'L', 0.059),
    (b'A', 0.058),
    (b'N', 0.051),
    (b'D', 0.049),
    (b'M', 0.046),
    (b'E', 0.039),
    (b'I', 0.035),
    (b'R', 0.035),
    (b'G', 0.028),
    (b'U', 0.026),
    (b'W', 0.025),
    (b'O', 0.017),
    (b'V', 0.015),
    (b'H', 0.013),
    (b'Q', 0.011),
    (b'J', 0.007),
    (b'K', 0.005),
    (b'+', 0.004),
    (b'X', 0.003),
    (b'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(b'.hg .i .d'.split())

# The last component of a path, before a slash or at the end of a name.

lasttable = resttable + (
    (lambda rng: b'', 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 b''.join(ps)


def makepath(rng, j, k):
    '''Construct a complete pathname.'''

    return (
        b'data/'
        + b'/'.join(makepart(rng, k) for _ in xrange(j))
        + rng.choice([b'.d', b'.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('seed:', hex(seed)[:-1], file=sys.stderr)
            print("\np: '%s'" % p.encode("string_escape"), file=sys.stderr)
            print("h: '%s'" % h.encode("string_escape"), file=sys.stderr)
            print("r: '%s'" % r.encode("string_escape"), file=sys.stderr)
            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 = int(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 = int(binascii.hexlify(os.urandom(16)), 16)
        except AttributeError:
            seed = int(time.time() * 1000)

    rng = random.Random(seed)
    if runtests(rng, seed, count):
        sys.exit(1)


if __name__ == '__main__':
    main()