branchcache: stop writing more branchcache file on disk than needed
Before this change, we were unconditionally writing a branchmap file for the
filter level passed to `update_disk`. This is actually counter productive if no
update were needed for this filter level. In many case, the branch cache for a
filter level is identical to its parent "subset" and it is better to simply
keep the subset update and reuse it every time instead of having to do identical
work for similar subset.
So we change the `update_disk` method to only write a file when that filter
level differ from its parent. This removes many cases where identical files were
written, requiring multiple boring update in the test suite.
The only notable changes is the change to `test-strip-branch-cache.t`, this
case was checking a scenario that no longer reproduce the bug as writing less
branchmap file result in less stalled cache on disk.
Strictly speaking, we could create a more convoluted scenario that create a
similar issue. However the next changeset would also cover that scenario so we
directly updated that test case to a "no longer buggy" state.
# Copyright 2009-2010 Gregory P. Ward
# Copyright 2009-2010 Intelerad Medical Systems Incorporated
# Copyright 2010-2011 Fog Creek Software
# Copyright 2010-2011 Unity Technologies
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''base class for store implementations and store-related utility code'''
from mercurial.i18n import _
from mercurial.node import short
from mercurial import util
from mercurial.utils import (
urlutil,
)
from . import lfutil
class StoreError(Exception):
"""Raised when there is a problem getting files from or putting
files to a central store."""
def __init__(self, filename, hash, url, detail):
self.filename = filename
self.hash = hash
self.url = url
self.detail = detail
def longmessage(self):
return _(b"error getting id %s from url %s for file %s: %s\n") % (
self.hash,
urlutil.hidepassword(self.url),
self.filename,
self.detail,
)
def __str__(self):
return b"%s: %s" % (urlutil.hidepassword(self.url), self.detail)
class basestore:
def __init__(self, ui, repo, url):
self.ui = ui
self.repo = repo
self.url = url
def put(self, source, hash):
'''Put source file into the store so it can be retrieved by hash.'''
raise NotImplementedError(b'abstract method')
def exists(self, hashes):
"""Check to see if the store contains the given hashes. Given an
iterable of hashes it returns a mapping from hash to bool."""
raise NotImplementedError(b'abstract method')
def get(self, files):
"""Get the specified largefiles from the store and write to local
files under repo.root. files is a list of (filename, hash)
tuples. Return (success, missing), lists of files successfully
downloaded and those not found in the store. success is a list
of (filename, hash) tuples; missing is a list of filenames that
we could not get. (The detailed error message will already have
been presented to the user, so missing is just supplied as a
summary.)"""
success = []
missing = []
ui = self.ui
at = 0
available = self.exists({hash for (_filename, hash) in files})
with ui.makeprogress(
_(b'getting largefiles'), unit=_(b'files'), total=len(files)
) as progress:
for filename, hash in files:
progress.update(at)
at += 1
ui.note(_(b'getting %s:%s\n') % (filename, hash))
if not available.get(hash):
ui.warn(
_(b'%s: largefile %s not available from %s\n')
% (filename, hash, urlutil.hidepassword(self.url))
)
missing.append(filename)
continue
if self._gethash(filename, hash):
success.append((filename, hash))
else:
missing.append(filename)
return (success, missing)
def _gethash(self, filename, hash):
"""Get file with the provided hash and store it in the local repo's
store and in the usercache.
filename is for informational messages only.
"""
util.makedirs(lfutil.storepath(self.repo, b''))
storefilename = lfutil.storepath(self.repo, hash)
tmpname = storefilename + b'.tmp'
with util.atomictempfile(
tmpname, createmode=self.repo.store.createmode
) as tmpfile:
try:
gothash = self._getfile(tmpfile, filename, hash)
except StoreError as err:
self.ui.warn(err.longmessage())
gothash = b""
if gothash != hash:
if gothash != b"":
self.ui.warn(
_(b'%s: data corruption (expected %s, got %s)\n')
% (filename, hash, gothash)
)
util.unlink(tmpname)
return False
util.rename(tmpname, storefilename)
lfutil.linktousercache(self.repo, hash)
return True
def verify(self, revs, contents=False):
"""Verify the existence (and, optionally, contents) of every big
file revision referenced by every changeset in revs.
Return 0 if all is well, non-zero on any errors."""
self.ui.status(
_(b'searching %d changesets for largefiles\n') % len(revs)
)
verified = set() # set of (filename, filenode) tuples
filestocheck = [] # list of (cset, filename, expectedhash)
for rev in revs:
cctx = self.repo[rev]
cset = b"%d:%s" % (cctx.rev(), short(cctx.node()))
for standin in cctx:
filename = lfutil.splitstandin(standin)
if filename:
fctx = cctx[standin]
key = (filename, fctx.filenode())
if key not in verified:
verified.add(key)
expectedhash = lfutil.readasstandin(fctx)
filestocheck.append((cset, filename, expectedhash))
failed = self._verifyfiles(contents, filestocheck)
numrevs = len(verified)
numlfiles = len({fname for (fname, fnode) in verified})
if contents:
self.ui.status(
_(b'verified contents of %d revisions of %d largefiles\n')
% (numrevs, numlfiles)
)
else:
self.ui.status(
_(b'verified existence of %d revisions of %d largefiles\n')
% (numrevs, numlfiles)
)
return int(failed)
def _getfile(self, tmpfile, filename, hash):
"""Fetch one revision of one file from the store and write it
to tmpfile. Compute the hash of the file on-the-fly as it
downloads and return the hash. Close tmpfile. Raise
StoreError if unable to download the file (e.g. it does not
exist in the store)."""
raise NotImplementedError(b'abstract method')
def _verifyfiles(self, contents, filestocheck):
"""Perform the actual verification of files in the store.
'contents' controls verification of content hash.
'filestocheck' is list of files to check.
Returns _true_ if any problems are found!
"""
raise NotImplementedError(b'abstract method')