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Differential D7257

[RFC] repoview: add a "filter" that just disallows walking to heads
Needs RevisionPublic

Authored by martinvonz on Nov 6 2019, 12:01 PM.

Details

Reviewers
durin42
baymax
Group Reviewers
hg-reviewers
Summary

This can let us find bugs where we think it shouldn't matter whether
we're using an unfiltered or filtered repo. We could then get a repo
that is using this new "filter" and if the code ends up trying to walk
the graph towards the changelog children, we would notice that.

Diff Detail

Repository
rHG Mercurial
Lint
Lint Skipped
Unit
Unit Tests Skipped

Event Timeline

martinvonz created this revision.Nov 6 2019, 12:01 PM
martinvonz updated this revision to Diff 18048.Nov 12 2019, 4:33 PM
marmoute added a subscriber: marmoute.Nov 12 2019, 5:06 PM

Can you elaborate on what this changeset is about ? the description is a bit… short;-)

martinvonz edited the summary of this revision. (Show Details)Nov 12 2019, 5:21 PM
martinvonz added a comment.Nov 12 2019, 5:21 PM
In D7257#108377, @marmoute wrote:

Can you elaborate on what this changeset is about ? the description is a bit… short;-)

Done.

durin42 accepted this revision as: durin42.Nov 13 2019, 6:10 PM
durin42 added a subscriber: durin42.

I'm a big fan of this idea. I'd probably land it if there were some obvious usecases as child patches. :)

baymax requested changes to this revision.Feb 21 2020, 3:50 AM

There seems to have been no activities on this Diff for the past 3 Months.

By policy, we are automatically moving it out of the need-review state.

Please, move it back to need-review without hesitation if this diff should still be discussed.

:baymax:need-review-idle:

This revision now requires changes to proceed.Feb 21 2020, 3:50 AM

Revision Contents
Changeset List

PathPackages
Mmercurial/commands.py (2 lines)
Mmercurial/repoview.py (28 lines)

Diff 18048

mercurial/commands.py

Extracted to a function so extensions can override it. Extracted to a function so extensions can override it.
""" """
use_unfiltered = False use_unfiltered = False
if commandname == b'status': if commandname == b'status':
if not kwargs.get(b'rev') and not kwargs.get(b'change'): if not kwargs.get(b'rev') and not kwargs.get(b'change'):
use_unfiltered = True use_unfiltered = True
return repo.unfiltered() if use_unfiltered else repo return repo.filtered(b'notreally') if use_unfiltered else repo
# Commands start here, listed alphabetically # Commands start here, listed alphabetically
@command( @command(
b'abort', b'abort',
dryrunopts, dryrunopts,

mercurial/repoview.py

# function to compute filtered set # function to compute filtered set
# #
# When adding a new filter you MUST update the table at: # When adding a new filter you MUST update the table at:
# mercurial.utils.repoviewutil.subsettable # mercurial.utils.repoviewutil.subsettable
# Otherwise your filter will have to recompute all its branches cache # Otherwise your filter will have to recompute all its branches cache
# from scratch (very slow). # from scratch (very slow).
filtertable = { filtertable = {
b'notreally': lambda repo, visibilityexceptions=None: frozenset(),
b'visible': computehidden, b'visible': computehidden,
b'visible-hidden': computehidden, b'visible-hidden': computehidden,
b'served.hidden': computesecret, b'served.hidden': computesecret,
b'served': computeunserved, b'served': computeunserved,
b'immutable': computemutable, b'immutable': computemutable,
b'base': computeimpactable, b'base': computeimpactable,
} }
def flags(self, rev): def flags(self, rev):
"""filtered version of revlog.flags""" """filtered version of revlog.flags"""
if rev in self.filteredrevs: if rev in self.filteredrevs:
raise error.FilteredIndexError(rev) raise error.FilteredIndexError(rev)
return super(filteredchangelogmixin, self).flags(rev) return super(filteredchangelogmixin, self).flags(rev)
def poisonwalktoheads(unfichangelog):
cl = copy.copy(unfichangelog)
def poison(*args, **kwargs):
raise error.ProgrammingError('called method on changelog that requries '
'filtering, but filtering was not requested')
class filteredchangelog(cl.__class__):
tiprev = poison
headrevs = poison
__iter__ = poison
children = poison
cl.__class__ = filteredchangelog
return cl
class repoview(object): class repoview(object):
"""Provide a read/write view of a repo through a filtered changelog """Provide a read/write view of a repo through a filtered changelog
This object is used to access a filtered version of a repository without This object is used to access a filtered version of a repository without
altering the original repository object itself. We can not alter the altering the original repository object itself. We can not alter the
original object for two main reasons: original object for two main reasons:
- It prevents the use of a repo with multiple filters at the same time. In - It prevents the use of a repo with multiple filters at the same time. In
particular when multiple threads are involved. particular when multiple threads are involved.
# if cl.index is not unfiindex, unfi.changelog would be # if cl.index is not unfiindex, unfi.changelog would be
# recreated, and our clcache refers to garbage object # recreated, and our clcache refers to garbage object
if cl is not None and ( if cl is not None and (
cl.index is not unfiindex or newkey != self._clcachekey cl.index is not unfiindex or newkey != self._clcachekey
): ):
cl = None cl = None
# could have been made None by the previous if # could have been made None by the previous if
if cl is None: if cl is None:
if self.filtername == b'notreally':
cl = poisonwalktoheads(unfichangelog)
elif revs:
# Only filter if there's something to filter # Only filter if there's something to filter
cl = wrapchangelog(unfichangelog, revs) if revs else unfichangelog cl = wrapchangelog(unfichangelog, revs)
else:
cl = unfichangelog
object.__setattr__(self, '_clcache', cl) object.__setattr__(self, '_clcache', cl)
object.__setattr__(self, '_clcachekey', newkey) object.__setattr__(self, '_clcachekey', newkey)
return cl return cl
def unfiltered(self): def unfiltered(self):
"""Return an unfiltered version of a repo""" """Return an unfiltered version of a repo"""
return self._unfilteredrepo return self._unfilteredrepo