view tests/test-filecache.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 b3684fd2ff1a
children ce26928cbe41
line wrap: on
line source

import sys, os, subprocess

if subprocess.call(['python', '%s/hghave' % os.environ['TESTDIR'],
                    'cacheable']):
    sys.exit(80)

from mercurial import util, scmutil, extensions, hg, ui

filecache = scmutil.filecache

class fakerepo(object):
    def __init__(self):
        self._filecache = {}

    def join(self, p):
        return p

    def sjoin(self, p):
        return p

    @filecache('x', 'y')
    def cached(self):
        print 'creating'
        return 'string from function'

    def invalidate(self):
        for k in self._filecache:
            try:
                delattr(self, k)
            except AttributeError:
                pass

def basic(repo):
    print "* neither file exists"
    # calls function
    repo.cached

    repo.invalidate()
    print "* neither file still exists"
    # uses cache
    repo.cached

    # create empty file
    f = open('x', 'w')
    f.close()
    repo.invalidate()
    print "* empty file x created"
    # should recreate the object
    repo.cached

    f = open('x', 'w')
    f.write('a')
    f.close()
    repo.invalidate()
    print "* file x changed size"
    # should recreate the object
    repo.cached

    repo.invalidate()
    print "* nothing changed with either file"
    # stats file again, reuses object
    repo.cached

    # atomic replace file, size doesn't change
    # hopefully st_mtime doesn't change as well so this doesn't use the cache
    # because of inode change
    f = scmutil.opener('.')('x', 'w', atomictemp=True)
    f.write('b')
    f.close()

    repo.invalidate()
    print "* file x changed inode"
    repo.cached

    # create empty file y
    f = open('y', 'w')
    f.close()
    repo.invalidate()
    print "* empty file y created"
    # should recreate the object
    repo.cached

    f = open('y', 'w')
    f.write('A')
    f.close()
    repo.invalidate()
    print "* file y changed size"
    # should recreate the object
    repo.cached

    f = scmutil.opener('.')('y', 'w', atomictemp=True)
    f.write('B')
    f.close()

    repo.invalidate()
    print "* file y changed inode"
    repo.cached

    f = scmutil.opener('.')('x', 'w', atomictemp=True)
    f.write('c')
    f.close()
    f = scmutil.opener('.')('y', 'w', atomictemp=True)
    f.write('C')
    f.close()

    repo.invalidate()
    print "* both files changed inode"
    repo.cached

def fakeuncacheable():
    def wrapcacheable(orig, *args, **kwargs):
        return False

    def wrapinit(orig, *args, **kwargs):
        pass

    originit = extensions.wrapfunction(util.cachestat, '__init__', wrapinit)
    origcacheable = extensions.wrapfunction(util.cachestat, 'cacheable',
                                            wrapcacheable)

    for fn in ['x', 'y']:
        try:
            os.remove(fn)
        except OSError:
            pass

    basic(fakerepo())

    util.cachestat.cacheable = origcacheable
    util.cachestat.__init__ = originit

def test_filecache_synced():
    # test old behaviour that caused filecached properties to go out of sync
    os.system('hg init && echo a >> a && hg ci -qAm.')
    repo = hg.repository(ui.ui())
    # first rollback clears the filecache, but changelog to stays in __dict__
    repo.rollback()
    repo.commit('.')
    # second rollback comes along and touches the changelog externally
    # (file is moved)
    repo.rollback()
    # but since changelog isn't under the filecache control anymore, we don't
    # see that it changed, and return the old changelog without reconstructing
    # it
    repo.commit('.')

def setbeforeget(repo):
    os.remove('x')
    os.remove('y')
    repo.cached = 'string set externally'
    repo.invalidate()
    print "* neither file exists"
    print repo.cached
    repo.invalidate()
    f = open('x', 'w')
    f.write('a')
    f.close()
    print "* file x created"
    print repo.cached

    repo.cached = 'string 2 set externally'
    repo.invalidate()
    print "* string set externally again"
    print repo.cached

    repo.invalidate()
    f = open('y', 'w')
    f.write('b')
    f.close()
    print "* file y created"
    print repo.cached

print 'basic:'
print
basic(fakerepo())
print
print 'fakeuncacheable:'
print
fakeuncacheable()
test_filecache_synced()
print
print 'setbeforeget:'
print
setbeforeget(fakerepo())