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Differential D8528

dirstate: make sure the dirstate is loaded before the changelog (issue6303)
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Authored by marmoute on May 15 2020, 6:22 AM.

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rHG35b255e474d9: dirstate: make sure the dirstate is loaded before the changelog (issue6303)
Summary

Before this change, it was possible for the changelog to be loaded before the
dirstate. If a transaction happens betwen the changelog and dirstate reading,
the dirstate can up end poitning toward a revision not existing in the (olded)
changelog. This lead to a warning.

With this revision, we preload the dirstate parent before reading the changelog.
This has a negligible performance impact on performance for all case we are
tracking.

Diff Detail

Repository
rHG Mercurial
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

Event Timeline

marmoute created this revision.May 15 2020, 6:22 AM
marmoute added a commit: rHG35b255e474d9: dirstate: make sure the dirstate is loaded before the changelog (issue6303).May 15 2020, 3:29 PM
This revision was not accepted when it landed; it landed in state Needs Review.
Closed by commit rHG35b255e474d9: dirstate: make sure the dirstate is loaded before the changelog (issue6303) (authored by marmoute). · Explain Why
This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

PathPackages
Mmercurial/dirstate.py (7 lines)
Mmercurial/localrepo.py (2 lines)
Mtests/test-static-http.t (5 lines)

Diff 21392

mercurial/dirstate.py

self._origpl = None self._origpl = None
self._updatedfiles = set() self._updatedfiles = set()
self._mapcls = dirstatemap self._mapcls = dirstatemap
# Access and cache cwd early, so we don't access it for the first time # Access and cache cwd early, so we don't access it for the first time
# after a working-copy update caused it to not exist (accessing it then # after a working-copy update caused it to not exist (accessing it then
# raises an exception). # raises an exception).
self._cwd self._cwd
def prefetch_parents(self):
"""make sure the parents are loaded
Used to avoid a race condition.
"""
self._pl
@contextlib.contextmanager @contextlib.contextmanager
def parentchange(self): def parentchange(self):
'''Context manager for handling dirstate parents. '''Context manager for handling dirstate parents.
If an exception occurs in the scope of the context manager, If an exception occurs in the scope of the context manager,
the incoherent dirstate won't be written when wlock is the incoherent dirstate won't be written when wlock is
released. released.
''' '''

mercurial/localrepo.py

return phases.phasecache(self, self._phasedefaults) return phases.phasecache(self, self._phasedefaults)
@storecache(b'obsstore') @storecache(b'obsstore')
def obsstore(self): def obsstore(self):
return obsolete.makestore(self.ui, self) return obsolete.makestore(self.ui, self)
@storecache(b'00changelog.i') @storecache(b'00changelog.i')
def changelog(self): def changelog(self):
# load dirstate before changelog to avoid race see issue6303
self.dirstate.prefetch_parents()
return self.store.changelog(txnutil.mayhavepending(self.root)) return self.store.changelog(txnutil.mayhavepending(self.root))
@storecache(b'00manifest.i') @storecache(b'00manifest.i')
def manifestlog(self): def manifestlog(self):
return self.store.manifestlog(self, self._storenarrowmatch) return self.store.manifestlog(self, self._storenarrowmatch)
@repofilecache(b'dirstate') @repofilecache(b'dirstate')
def dirstate(self): def dirstate(self):

tests/test-static-http.t

List of files accessed over HTTP: List of files accessed over HTTP:
$ cat server.log | sed -n -e 's|.*GET \(/[^ ]*\).*|\1|p' | sort -u $ cat server.log | sed -n -e 's|.*GET \(/[^ ]*\).*|\1|p' | sort -u
/.hg/bookmarks /.hg/bookmarks
/.hg/bookmarks.current /.hg/bookmarks.current
/.hg/cache/hgtagsfnodes1 /.hg/cache/hgtagsfnodes1
/.hg/cache/rbc-names-v1 /.hg/cache/rbc-names-v1
/.hg/cache/rbc-revs-v1 /.hg/cache/rbc-revs-v1
/.hg/dirstate
/.hg/requires /.hg/requires
/.hg/store/00changelog.i /.hg/store/00changelog.i
/.hg/store/00manifest.i /.hg/store/00manifest.i
/.hg/store/data/%7E2ehgsub.i (no-py37 !) /.hg/store/data/%7E2ehgsub.i (no-py37 !)
/.hg/store/data/%7E2ehgsubstate.i (no-py37 !) /.hg/store/data/%7E2ehgsubstate.i (no-py37 !)
/.hg/store/data/a.i /.hg/store/data/a.i
/.hg/store/data/~2ehgsub.i (py37 !) /.hg/store/data/~2ehgsub.i (py37 !)
/.hg/store/data/~2ehgsubstate.i (py37 !) /.hg/store/data/~2ehgsubstate.i (py37 !)
/notarepo/.hg/00changelog.i /notarepo/.hg/00changelog.i
/notarepo/.hg/requires /notarepo/.hg/requires
/remote-with-names/.hg/bookmarks /remote-with-names/.hg/bookmarks
/remote-with-names/.hg/bookmarks.current /remote-with-names/.hg/bookmarks.current
/remote-with-names/.hg/cache/branch2-served /remote-with-names/.hg/cache/branch2-served
/remote-with-names/.hg/cache/hgtagsfnodes1 /remote-with-names/.hg/cache/hgtagsfnodes1
/remote-with-names/.hg/cache/rbc-names-v1 /remote-with-names/.hg/cache/rbc-names-v1
/remote-with-names/.hg/cache/rbc-revs-v1 /remote-with-names/.hg/cache/rbc-revs-v1
/remote-with-names/.hg/cache/tags2-served /remote-with-names/.hg/cache/tags2-served
/remote-with-names/.hg/dirstate
/remote-with-names/.hg/localtags /remote-with-names/.hg/localtags
/remote-with-names/.hg/requires /remote-with-names/.hg/requires
/remote-with-names/.hg/store/00changelog.i /remote-with-names/.hg/store/00changelog.i
/remote-with-names/.hg/store/00manifest.i /remote-with-names/.hg/store/00manifest.i
/remote-with-names/.hg/store/data/%7E2ehgtags.i (no-py37 !) /remote-with-names/.hg/store/data/%7E2ehgtags.i (no-py37 !)
/remote-with-names/.hg/store/data/foo.i /remote-with-names/.hg/store/data/foo.i
/remote-with-names/.hg/store/data/~2ehgtags.i (py37 !) /remote-with-names/.hg/store/data/~2ehgtags.i (py37 !)
/remote/.hg/bookmarks /remote/.hg/bookmarks
/remote/.hg/bookmarks.current /remote/.hg/bookmarks.current
/remote/.hg/cache/branch2-base /remote/.hg/cache/branch2-base
/remote/.hg/cache/branch2-immutable /remote/.hg/cache/branch2-immutable
/remote/.hg/cache/branch2-served /remote/.hg/cache/branch2-served
/remote/.hg/cache/hgtagsfnodes1 /remote/.hg/cache/hgtagsfnodes1
/remote/.hg/cache/rbc-names-v1 /remote/.hg/cache/rbc-names-v1
/remote/.hg/cache/rbc-revs-v1 /remote/.hg/cache/rbc-revs-v1
/remote/.hg/cache/tags2-served /remote/.hg/cache/tags2-served
/remote/.hg/dirstate
/remote/.hg/localtags /remote/.hg/localtags
/remote/.hg/requires /remote/.hg/requires
/remote/.hg/store/00changelog.i /remote/.hg/store/00changelog.i
/remote/.hg/store/00manifest.i /remote/.hg/store/00manifest.i
/remote/.hg/store/data/%7E2edotfile%20with%20spaces.i (no-py37 !) /remote/.hg/store/data/%7E2edotfile%20with%20spaces.i (no-py37 !)
/remote/.hg/store/data/%7E2ehgtags.i (no-py37 !) /remote/.hg/store/data/%7E2ehgtags.i (no-py37 !)
/remote/.hg/store/data/bar.i /remote/.hg/store/data/bar.i
/remote/.hg/store/data/quux.i /remote/.hg/store/data/quux.i
/remote/.hg/store/data/~2edotfile%20with%20spaces.i (py37 !) /remote/.hg/store/data/~2edotfile%20with%20spaces.i (py37 !)
/remote/.hg/store/data/~2ehgtags.i (py37 !) /remote/.hg/store/data/~2ehgtags.i (py37 !)
/remotempty/.hg/bookmarks /remotempty/.hg/bookmarks
/remotempty/.hg/bookmarks.current /remotempty/.hg/bookmarks.current
/remotempty/.hg/dirstate
/remotempty/.hg/requires /remotempty/.hg/requires
/remotempty/.hg/store/00changelog.i /remotempty/.hg/store/00changelog.i
/remotempty/.hg/store/00manifest.i /remotempty/.hg/store/00manifest.i
/sub/.hg/bookmarks /sub/.hg/bookmarks
/sub/.hg/bookmarks.current /sub/.hg/bookmarks.current
/sub/.hg/cache/hgtagsfnodes1 /sub/.hg/cache/hgtagsfnodes1
/sub/.hg/cache/rbc-names-v1 /sub/.hg/cache/rbc-names-v1
/sub/.hg/cache/rbc-revs-v1 /sub/.hg/cache/rbc-revs-v1
/sub/.hg/dirstate
/sub/.hg/requires /sub/.hg/requires
/sub/.hg/store/00changelog.i /sub/.hg/store/00changelog.i
/sub/.hg/store/00manifest.i /sub/.hg/store/00manifest.i
/sub/.hg/store/data/%7E2ehgtags.i (no-py37 !) /sub/.hg/store/data/%7E2ehgtags.i (no-py37 !)
/sub/.hg/store/data/test.i /sub/.hg/store/data/test.i
/sub/.hg/store/data/~2ehgtags.i (py37 !) /sub/.hg/store/data/~2ehgtags.i (py37 !)