Mercurial > hg
view tests/test-contrib-check-code.t @ 43709:039fbd14d4e2
lock: fix race in lock-breaking code
With low frequency, I see hg pulls fail with output like:
abort: no such file or directory: .hg/store/lock
I think what happens is, in lock.py, in:
def _testlock(self, locker):
if not self._lockshouldbebroken(locker):
return locker
# if locker dead, break lock. must do this with another lock
# held, or can race and break valid lock.
try:
with lock(self.vfs, self.f + b'.break', timeout=0):
self.vfs.unlink(self.f)
except error.LockError:
return locker
if a lock is breakable on disk, and two hg processes concurrently get
to the "if locker dead" comment, a possible interleaving is: process1
finishes executing the function and then process2 finishes executing
the function. If that happens, process2 will either get ENOENT in
self.vfs.unlink (resulting in the spurious failure above), or break a
valid lock and potentially cause repository corruption.
The fix is simple enough: make sure the lock is breakable _inside_ the
critical section, because only then can we know that no other process
can invalidate our knowledge on the lock on disk.
I don't think there are tests for this. I've tested this manually
with:
diff --git a/mercurial/lock.py b/mercurial/lock.py
--- a/mercurial/lock.py
+++ b/mercurial/lock.py
@@ -351,6 +351,8 @@ class lock(object):
if not self._lockshouldbebroken(locker):
return locker
+ import random
+ time.sleep(1. + random.random())
# if locker dead, break lock. must do this with another lock
# held, or can race and break valid lock.
try:
@@ -358,6 +360,7 @@ class lock(object):
self.vfs.unlink(self.f)
except error.LockError:
return locker
+ time.sleep(1)
def testlock(self):
"""return id of locker if lock is valid, else None.
and I see this change of behavior before/after this commit:
$ $hg init repo
$ cd repo
$ ln -s $HOSTNAME/effffffc:987654321 .hg/wlock
$ touch a
$ $hg commit -Am_ & $hg commit -Am _; wait
-abort: No such file or directory: '/tmp/repo/.hg/wlock'
adding a
+warning: ignoring unknown working parent 679a8959a8ca!
+nothing changed
Differential Revision: https://phab.mercurial-scm.org/D7199
author | Valentin Gatien-Baron <valentin.gatienbaron@gmail.com> |
---|---|
date | Mon, 18 Nov 2019 20:10:38 -0800 |
parents | 867883d454ea |
children | 55d132525155 |
line wrap: on
line source
$ cat > correct.py <<NO_CHECK_EOF > def toto(arg1, arg2): > del arg2 > return (5 + 6, 9) > NO_CHECK_EOF $ cat > wrong.py <<NO_CHECK_EOF > def toto( arg1, arg2): > del(arg2) > return ( 5+6, 9) > def badwrap(): > return 1 + \\ > 2 > NO_CHECK_EOF $ cat > quote.py <<NO_CHECK_EOF > # let's use quote in comments > (''' ( 4x5 ) > but """\\''' and finally''', > """let's fool checkpatch""", '1+2', > '"""', 42+1, """and > ( 4-1 ) """, "( 1+1 )\" and ") > a, '\\\\\\\\', "\\\\\\" x-2", "c-1" > NO_CHECK_EOF $ cat > classstyle.py <<NO_CHECK_EOF > class newstyle_class(object): > pass > > class oldstyle_class: > pass > > class empty(): > pass > > no_class = 1: > pass > NO_CHECK_EOF $ check_code="$TESTDIR"/../contrib/check-code.py $ "$check_code" ./wrong.py ./correct.py ./quote.py ./classstyle.py ./wrong.py:1: > def toto( arg1, arg2): gratuitous whitespace in () or [] ./wrong.py:2: > del(arg2) Python keyword is not a function ./wrong.py:3: > return ( 5+6, 9) gratuitous whitespace in () or [] missing whitespace in expression ./wrong.py:5: > return 1 + \ Use () to wrap long lines in Python, not \ ./quote.py:5: > '"""', 42+1, """and missing whitespace in expression ./classstyle.py:4: > class oldstyle_class: old-style class, use class foo(object) ./classstyle.py:7: > class empty(): class foo() creates old style object, use class foo(object) [1] $ cat > python3-compat.py << NO_CHECK_EOF > foo <> bar > reduce(lambda a, b: a + b, [1, 2, 3, 4]) > dict(key=value) > NO_CHECK_EOF $ "$check_code" python3-compat.py python3-compat.py:1: > foo <> bar <> operator is not available in Python 3+, use != python3-compat.py:2: > reduce(lambda a, b: a + b, [1, 2, 3, 4]) reduce is not available in Python 3+ python3-compat.py:3: > dict(key=value) dict() is different in Py2 and 3 and is slower than {} [1] $ cat > foo.c <<NO_CHECK_EOF > void narf() { > strcpy(foo, bar); > // strcpy_s is okay, but this comment is not > strcpy_s(foo, bar); > } > NO_CHECK_EOF $ "$check_code" ./foo.c ./foo.c:2: > strcpy(foo, bar); don't use strcpy, use strlcpy or memcpy ./foo.c:3: > // strcpy_s is okay, but this comment is not don't use //-style comments [1] $ cat > is-op.py <<NO_CHECK_EOF > # is-operator comparing number or string literal > x = None > y = x is 'foo' > y = x is "foo" > y = x is 5346 > y = x is -6 > y = x is not 'foo' > y = x is not "foo" > y = x is not 5346 > y = x is not -6 > NO_CHECK_EOF $ "$check_code" ./is-op.py ./is-op.py:3: > y = x is 'foo' object comparison with literal ./is-op.py:4: > y = x is "foo" object comparison with literal ./is-op.py:5: > y = x is 5346 object comparison with literal ./is-op.py:6: > y = x is -6 object comparison with literal ./is-op.py:7: > y = x is not 'foo' object comparison with literal ./is-op.py:8: > y = x is not "foo" object comparison with literal ./is-op.py:9: > y = x is not 5346 object comparison with literal ./is-op.py:10: > y = x is not -6 object comparison with literal [1] $ cat > for-nolineno.py <<NO_CHECK_EOF > except: > NO_CHECK_EOF $ "$check_code" for-nolineno.py --nolineno for-nolineno.py:0: > except: naked except clause [1] $ cat > warning.t <<NO_CHECK_EOF > $ function warnonly { > > } > $ diff -N aaa > $ function onwarn {} > NO_CHECK_EOF $ "$check_code" warning.t $ "$check_code" --warn warning.t warning.t:1: > $ function warnonly { warning: don't use 'function', use old style warning.t:3: > $ diff -N aaa warning: don't use 'diff -N' warning.t:4: > $ function onwarn {} warning: don't use 'function', use old style [1] $ cat > error.t <<NO_CHECK_EOF > $ [ foo == bar ] > NO_CHECK_EOF $ "$check_code" error.t error.t:1: > $ [ foo == bar ] [ foo == bar ] is a bashism, use [ foo = bar ] instead [1] $ rm error.t $ cat > raise-format.py <<NO_CHECK_EOF > raise SomeException, message > # this next line is okay > raise SomeException(arg1, arg2) > NO_CHECK_EOF $ "$check_code" not-existing.py raise-format.py Skipping*not-existing.py* (glob) raise-format.py:1: > raise SomeException, message don't use old-style two-argument raise, use Exception(message) [1] $ cat <<NO_CHECK_EOF > tab.t > indent > > heredoc > NO_CHECK_EOF $ "$check_code" tab.t tab.t:1: > indent don't use tabs to indent [1] $ rm tab.t $ cat > rst.py <<NO_CHECK_EOF > """problematic rst text > > .. note:: > wrong > """ > > ''' > > .. note:: > > valid > > new text > > .. note:: > > also valid > ''' > > """mixed > > .. note:: > > good > > .. note:: > plus bad > """ > NO_CHECK_EOF $ $check_code -w rst.py rst.py:3: > .. note:: warning: add two newlines after '.. note::' rst.py:26: > .. note:: warning: add two newlines after '.. note::' [1] $ cat > ./map-inside-gettext.py <<NO_CHECK_EOF > print(_("map inside gettext %s" % v)) > > print(_("concatenating " " by " " space %s" % v)) > print(_("concatenating " + " by " + " '+' %s" % v)) > > print(_("mapping operation in different line %s" > % v)) > > print(_( > "leading spaces inside of '(' %s" % v)) > NO_CHECK_EOF $ "$check_code" ./map-inside-gettext.py ./map-inside-gettext.py:1: > print(_("map inside gettext %s" % v)) don't use % inside _() ./map-inside-gettext.py:3: > print(_("concatenating " " by " " space %s" % v)) don't use % inside _() ./map-inside-gettext.py:4: > print(_("concatenating " + " by " + " '+' %s" % v)) don't use % inside _() ./map-inside-gettext.py:6: > print(_("mapping operation in different line %s" don't use % inside _() ./map-inside-gettext.py:9: > print(_( don't use % inside _() [1] web templates $ mkdir -p mercurial/templates $ cat > mercurial/templates/example.tmpl <<NO_CHECK_EOF > {desc} > {desc|escape} > {desc|firstline} > {desc|websub} > NO_CHECK_EOF $ "$check_code" --warnings mercurial/templates/example.tmpl mercurial/templates/example.tmpl:2: > {desc|escape} warning: follow desc keyword with either firstline or websub [1] 'string join across lines with no space' detection $ cat > stringjoin.py <<NO_CHECK_EOF > foo = (' foo' > 'bar foo.' > 'bar foo:' > 'bar foo@' > 'bar foo%' > 'bar foo*' > 'bar foo+' > 'bar foo-' > 'bar') > NO_CHECK_EOF 'missing _() in ui message' detection $ cat > uigettext.py <<NO_CHECK_EOF > ui.status("% 10s %05d % -3.2f %*s %%" > # this use '\\\\' instead of '\\', because the latter in > # heredoc on shell becomes just '\' > '\\\\ \n \t \0' > """12345 > """ > '''.:*+-= > ''' "%-6d \n 123456 .:*+-= foobar") > NO_CHECK_EOF superfluous pass $ cat > superfluous_pass.py <<NO_CHECK_EOF > # correct examples > if foo: > pass > else: > # comment-only line means still need pass > pass > def nothing(): > pass > class empty(object): > pass > if whatever: > passvalue(value) > # bad examples > if foo: > "foo" > pass > else: # trailing comment doesn't fool checker > wat() > pass > def nothing(): > "docstring means no pass" > pass > class empty(object): > """multiline > docstring also > means no pass""" > pass > NO_CHECK_EOF (Checking multiple invalid files at once examines whether caching translation table for repquote() works as expected or not. All files should break rules depending on result of repquote(), in this case) $ "$check_code" stringjoin.py uigettext.py superfluous_pass.py stringjoin.py:1: > foo = (' foo' string join across lines with no space stringjoin.py:2: > 'bar foo.' string join across lines with no space stringjoin.py:3: > 'bar foo:' string join across lines with no space stringjoin.py:4: > 'bar foo@' string join across lines with no space stringjoin.py:5: > 'bar foo%' string join across lines with no space stringjoin.py:6: > 'bar foo*' string join across lines with no space stringjoin.py:7: > 'bar foo+' string join across lines with no space stringjoin.py:8: > 'bar foo-' string join across lines with no space uigettext.py:1: > ui.status("% 10s %05d % -3.2f %*s %%" missing _() in ui message (use () to hide false-positives) superfluous_pass.py:14: > if foo: omit superfluous pass superfluous_pass.py:17: > else: # trailing comment doesn't fool checker omit superfluous pass superfluous_pass.py:20: > def nothing(): omit superfluous pass superfluous_pass.py:23: > class empty(object): omit superfluous pass [1] Check code fragments embedded in test script $ cat > embedded-code.t <<NO_CHECK_EOF > code fragment in doctest style > >>> x = (1,2) > ... > ... x = (1,2) > > code fragment in heredoc style > $ python <<EOF > > x = (1,2) > > EOF > > code fragment in file heredoc style > $ python > file.py <<EOF > > x = (1,2) > > EOF > NO_CHECK_EOF $ "$check_code" embedded-code.t embedded-code.t:2: > x = (1,2) missing whitespace after , embedded-code.t:4: > x = (1,2) missing whitespace after , embedded-code.t:8: > x = (1,2) missing whitespace after , embedded-code.t:13: > x = (1,2) missing whitespace after , [1] "max warnings per file" is shared by all embedded code fragments $ "$check_code" --per-file=3 embedded-code.t embedded-code.t:2: > x = (1,2) missing whitespace after , embedded-code.t:4: > x = (1,2) missing whitespace after , embedded-code.t:8: > x = (1,2) missing whitespace after , (too many errors, giving up) [1]