filectx: fix cmp() of file starting with '\1\n'
If file data starts with '\1\n', it will be escaped in the revlog to
create an empty metadata block, thus adding four bytes to the size in
the revlog size index. There's no way to detect that this has happened
in filelog.size() faster than decompressing each revision [1].
For filectx.cmp(), we have the size of the file in the working directory
available. If it differs by exactly four bytes, it may be this case, so
do a full comparison.
[1]: http://markmail.org/message/5akdbmmqx7vq2fsg
import sys, os, subprocess
if subprocess.call(['%s/hghave' % os.environ['TESTDIR'], 'cacheable']):
sys.exit(80)
from mercurial import util, scmutil, extensions
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')
def cached(self):
print 'creating'
def invalidate(self):
for k in self._filecache:
try:
delattr(self, k)
except AttributeError:
pass
def basic(repo):
# file doesn't exist, calls function
repo.cached
repo.invalidate()
# file still doesn't exist, uses cache
repo.cached
# create empty file
f = open('x', 'w')
f.close()
repo.invalidate()
# should recreate the object
repo.cached
f = open('x', 'w')
f.write('a')
f.close()
repo.invalidate()
# should recreate the object
repo.cached
repo.invalidate()
# stats file again, nothing changed, 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()
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)
try:
os.remove('x')
except:
pass
basic(fakerepo())
util.cachestat.cacheable = origcacheable
util.cachestat.__init__ = originit
print 'basic:'
print
basic(fakerepo())
print
print 'fakeuncacheable:'
print
fakeuncacheable()