view tests/test-ancestor.py @ 25757:4d1382fd96ff

context: write dirstate out explicitly at the end of markcommitted To detect change of a file without redundant comparison of file content, dirstate recognizes a file as certainly clean, if: (1) it is already known as "normal", (2) dirstate entry for it has valid (= not "-1") timestamp, and (3) mode, size and timestamp of it on the filesystem are as same as ones expected in dirstate This works as expected in many cases, but doesn't in the corner case that changing a file keeps mode, size and timestamp of it on the filesystem. The timetable below shows steps in one of typical such situations: ---- ----------------------------------- ---------------- timestamp of "f" ---------------- dirstate file- time action mem file system ---- ----------------------------------- ---- ----- ----- * *** *** - 'hg transplant REV1 REV2 ...' - transplanting REV1 .... N - change "f", but keep size N (via 'patch.patch()') - 'dirstate.normal("f")' N *** (via 'repo.commit()') - transplanting REV2 - change "f", but keep size N (via 'patch.patch()') - aborted while patching N+1 - release wlock - 'dirstate.write()' N N N - 'hg status' shows "r1" as "clean" N N N ---- ----------------------------------- ---- ----- ----- The most important point is that 'dirstate.write()' is executed at N+1 or later. This causes writing dirstate timestamp N of "f" out successfully. If it is executed at N, 'parsers.pack_dirstate()' replaces timestamp N with "-1" before actual writing dirstate out. This issue can occur when 'hg transplant' satisfies conditions below: - multiple revisions to be transplanted change the same file - those revisions don't change mode and size of the file, and - the 2nd or later revision of them fails after changing the file The root cause of this issue is that files are changed without flushing in-memory dirstate changes via 'repo.commit()' (even though omitting 'dirstate.normallookup()' on files changed by 'patch.patch()' for efficiency also causes this issue). To detect changes of files correctly, this patch writes in-memory dirstate changes out explicitly after marking files as clean in 'committablectx.markcommitted()', which is invoked via 'repo.commit()'. After this change, timetable is changed as below: ---- ----------------------------------- ---------------- timestamp of "f" ---------------- dirstate file- time action mem file system ---- ----------------------------------- ---- ----- ----- * *** *** - 'hg transplant REV1 REV2 ...' - transplanting REV1 .... N - change "f", but keep size N (via 'patch.patch()') - 'dirstate.normal("f")' N *** (via 'repo.commit()') ----------------------------------- ---- ----- ----- - 'dirsttate.write()' -1 -1 ----------------------------------- ---- ----- ----- - transplanting REV2 - change "f", but keep size N (via 'patch.patch()') - aborted while patching N+1 - release wlock - 'dirstate.write()' -1 -1 N - 'hg status' shows "r1" as "clean" -1 -1 N ---- ----------------------------------- ---- ----- ----- To reproduce this issue in tests certainly, this patch emulates some timing critical actions as below: - change "f" at N 'patch.patch()' with 'fakepatchtime.py' explicitly changes mtime of patched files to "2000-01-01 00:00" (= N). - 'dirstate.write()' via 'repo.commit()' at N 'fakedirstatewritetime.py' forces 'pack_dirstate()' to use "2000-01-01 00:00" as "now", only if 'pack_dirstate()' is invoked via 'committablectx.markcommitted()'. - 'dirstate.write()' via releasing wlock at N+1 (or "not at N") 'pack_dirstate()' via releasing wlock uses actual timestamp at runtime as "now", and it should be different from the "2000-01-01 00:00" of "f". BTW, this patch doesn't test cases below, even though 'patch.patch()' is used similarly in these cases: 1. failure of 'hg import' or 'hg qpush' 2. success of 'hg import', 'hg qpush' or 'hg transplant' Case (1) above doesn't cause this kind of issue, because: - if patching is aborted by conflicts, changed files are committed changed files are marked as CLEAN, even though they are partially patched. - otherwise, dirstate are fully restored by 'dirstateguard' For example in timetable above, timestamp of "f" in .hg/dirstate is restored to -1 (or less than N), and subsequent 'hg status' can detect changes correctly. Case (2) always causes 'repo.status()' invocation via 'repo.commit()' just after changing files inside same wlock scope. ---- ----------------------------------- ---------------- timestamp of "f" ---------------- dirstate file- time action mem file system ---- ----------------------------------- ---- ----- ----- N *** *** - make file "f" clean N - execute 'hg foobar' .... - 'dirstate.normal("f")' N *** (e.g. via dirty check or previous 'repo.commit()') - change "f", but keep size N - 'repo.status()' (*1) (via 'repo.commit()') ---- ----------------------------------- ---- ----- ----- At a glance, 'repo.status()' at (*1) seems to cause similar issue (= "changed files are treated as clean"), but actually doesn't. 'dirstate._lastnormaltime' should be N at (*1) above, because 'dirstate.normal()' via dirty check is finished at N. Therefore, "f" changed at N (= 'dirstate._lastnormaltime') is forcibly treated as "unsure" at (*1), and changes are detected as expected (see 'dirstate.status()' for detail). If 'hg import' is executed with '--no-commit', 'repo.status()' isn't invoked just after changing files inside same wlock scope. But preceding 'dirstate.normal()' is invoked inside another wlock scope via 'cmdutil.bailifchanged()', and in-memory changes should be flushed at the end of that scope. Therefore, timestamp N of clean "f" should be replaced by -1, if 'dirstate.write()' is invoked at N. It means that condition of this issue isn't satisfied.
author FUJIWARA Katsunori <foozy@lares.dti.ne.jp>
date Wed, 08 Jul 2015 17:01:09 +0900
parents f710644e1ce9
children 4056fdf71aff
line wrap: on
line source

from mercurial import ancestor, commands, hg, ui, util
from mercurial.node import nullrev
import binascii, getopt, math, os, random, sys, time

def buildgraph(rng, nodes=100, rootprob=0.05, mergeprob=0.2, prevprob=0.7):
    '''nodes: total number of nodes in the graph
    rootprob: probability that a new node (not 0) will be a root
    mergeprob: probability that, excluding a root a node will be a merge
    prevprob: probability that p1 will be the previous node

    return value is a graph represented as an adjacency list.
    '''
    graph = [None] * nodes
    for i in xrange(nodes):
        if i == 0 or rng.random() < rootprob:
            graph[i] = [nullrev]
        elif i == 1:
            graph[i] = [0]
        elif rng.random() < mergeprob:
            if i == 2 or rng.random() < prevprob:
                # p1 is prev
                p1 = i - 1
            else:
                p1 = rng.randrange(i - 1)
            p2 = rng.choice(range(0, p1) + range(p1 + 1, i))
            graph[i] = [p1, p2]
        elif rng.random() < prevprob:
            graph[i] = [i - 1]
        else:
            graph[i] = [rng.randrange(i - 1)]

    return graph

def buildancestorsets(graph):
    ancs = [None] * len(graph)
    for i in xrange(len(graph)):
        ancs[i] = set([i])
        if graph[i] == [nullrev]:
            continue
        for p in graph[i]:
            ancs[i].update(ancs[p])
    return ancs

class naiveincrementalmissingancestors(object):
    def __init__(self, ancs, bases):
        self.ancs = ancs
        self.bases = set(bases)
    def addbases(self, newbases):
        self.bases.update(newbases)
    def removeancestorsfrom(self, revs):
        for base in self.bases:
            if base != nullrev:
                revs.difference_update(self.ancs[base])
        revs.discard(nullrev)
    def missingancestors(self, revs):
        res = set()
        for rev in revs:
            if rev != nullrev:
                res.update(self.ancs[rev])
        for base in self.bases:
            if base != nullrev:
                res.difference_update(self.ancs[base])
        return sorted(res)

def test_missingancestors(seed, rng):
    # empirically observed to take around 1 second
    graphcount = 100
    testcount = 10
    inccount = 10
    nerrs = [0]
    # the default mu and sigma give us a nice distribution of mostly
    # single-digit counts (including 0) with some higher ones
    def lognormrandom(mu, sigma):
        return int(math.floor(rng.lognormvariate(mu, sigma)))

    def samplerevs(nodes, mu=1.1, sigma=0.8):
        count = min(lognormrandom(mu, sigma), len(nodes))
        return rng.sample(nodes, count)

    def err(seed, graph, bases, seq, output, expected):
        if nerrs[0] == 0:
            print >> sys.stderr, 'seed:', hex(seed)[:-1]
        if gerrs[0] == 0:
            print >> sys.stderr, 'graph:', graph
        print >> sys.stderr, '* bases:', bases
        print >> sys.stderr, '* seq: ', seq
        print >> sys.stderr, '*  output:  ', output
        print >> sys.stderr, '*  expected:', expected
        nerrs[0] += 1
        gerrs[0] += 1

    for g in xrange(graphcount):
        graph = buildgraph(rng)
        ancs = buildancestorsets(graph)
        gerrs = [0]
        for _ in xrange(testcount):
            # start from nullrev to include it as a possibility
            graphnodes = range(nullrev, len(graph))
            bases = samplerevs(graphnodes)

            # fast algorithm
            inc = ancestor.incrementalmissingancestors(graph.__getitem__, bases)
            # reference slow algorithm
            naiveinc = naiveincrementalmissingancestors(ancs, bases)
            seq = []
            revs = []
            for _ in xrange(inccount):
                if rng.random() < 0.2:
                    newbases = samplerevs(graphnodes)
                    seq.append(('addbases', newbases))
                    inc.addbases(newbases)
                    naiveinc.addbases(newbases)
                if rng.random() < 0.4:
                    # larger set so that there are more revs to remove from
                    revs = samplerevs(graphnodes, mu=1.5)
                    seq.append(('removeancestorsfrom', revs))
                    hrevs = set(revs)
                    rrevs = set(revs)
                    inc.removeancestorsfrom(hrevs)
                    naiveinc.removeancestorsfrom(rrevs)
                    if hrevs != rrevs:
                        err(seed, graph, bases, seq, sorted(hrevs),
                            sorted(rrevs))
                else:
                    revs = samplerevs(graphnodes)
                    seq.append(('missingancestors', revs))
                    h = inc.missingancestors(revs)
                    r = naiveinc.missingancestors(revs)
                    if h != r:
                        err(seed, graph, bases, seq, h, r)

# graph is a dict of child->parent adjacency lists for this graph:
# o  13
# |
# | o  12
# | |
# | | o    11
# | | |\
# | | | | o  10
# | | | | |
# | o---+ |  9
# | | | | |
# o | | | |  8
#  / / / /
# | | o |  7
# | | | |
# o---+ |  6
#  / / /
# | | o  5
# | |/
# | o  4
# | |
# o |  3
# | |
# | o  2
# |/
# o  1
# |
# o  0

graph = {0: [-1], 1: [0], 2: [1], 3: [1], 4: [2], 5: [4], 6: [4],
         7: [4], 8: [-1], 9: [6, 7], 10: [5], 11: [3, 7], 12: [9],
         13: [8]}

def genlazyancestors(revs, stoprev=0, inclusive=False):
    print ("%% lazy ancestor set for %s, stoprev = %s, inclusive = %s" %
           (revs, stoprev, inclusive))
    return ancestor.lazyancestors(graph.get, revs, stoprev=stoprev,
                                  inclusive=inclusive)

def printlazyancestors(s, l):
    print 'membership: %r' % [n for n in l if n in s]
    print 'iteration:  %r' % list(s)

def test_lazyancestors():
    # Empty revs
    s = genlazyancestors([])
    printlazyancestors(s, [3, 0, -1])

    # Standard example
    s = genlazyancestors([11, 13])
    printlazyancestors(s, [11, 13, 7, 9, 8, 3, 6, 4, 1, -1, 0])

    # Standard with ancestry in the initial set (1 is ancestor of 3)
    s = genlazyancestors([1, 3])
    printlazyancestors(s, [1, -1, 0])

    # Including revs
    s = genlazyancestors([11, 13], inclusive=True)
    printlazyancestors(s, [11, 13, 7, 9, 8, 3, 6, 4, 1, -1, 0])

    # Test with stoprev
    s = genlazyancestors([11, 13], stoprev=6)
    printlazyancestors(s, [11, 13, 7, 9, 8, 3, 6, 4, 1, -1, 0])
    s = genlazyancestors([11, 13], stoprev=6, inclusive=True)
    printlazyancestors(s, [11, 13, 7, 9, 8, 3, 6, 4, 1, -1, 0])


# The C gca algorithm requires a real repo. These are textual descriptions of
# DAGs that have been known to be problematic.
dagtests = [
    '+2*2*2/*3/2',
    '+3*3/*2*2/*4*4/*4/2*4/2*2',
]
def test_gca():
    u = ui.ui()
    for i, dag in enumerate(dagtests):
        repo = hg.repository(u, 'gca%d' % i, create=1)
        cl = repo.changelog
        if not util.safehasattr(cl.index, 'ancestors'):
            # C version not available
            return

        commands.debugbuilddag(u, repo, dag)
        # Compare the results of the Python and C versions. This does not
        # include choosing a winner when more than one gca exists -- we make
        # sure both return exactly the same set of gcas.
        for a in cl:
            for b in cl:
                cgcas = sorted(cl.index.ancestors(a, b))
                pygcas = sorted(ancestor.ancestors(cl.parentrevs, a, b))
                if cgcas != pygcas:
                    print "test_gca: for dag %s, gcas for %d, %d:" % (dag, a, b)
                    print "  C returned:      %s" % cgcas
                    print "  Python returned: %s" % pygcas

def main():
    seed = None
    opts, args = getopt.getopt(sys.argv[1:], 's:', ['seed='])
    for o, a in opts:
        if o in ('-s', '--seed'):
            seed = long(a, base=0) # accepts base 10 or 16 strings

    if seed is None:
        try:
            seed = long(binascii.hexlify(os.urandom(16)), 16)
        except AttributeError:
            seed = long(time.time() * 1000)

    rng = random.Random(seed)
    test_missingancestors(seed, rng)
    test_lazyancestors()
    test_gca()

if __name__ == '__main__':
    main()