narrow: remove narrowrevlog

Core now automatically enables ellipsis support on revlogs when
repositories have narrow enabled. So, we no longer need to globally
register the revlog flag as part of activating the narrow extension
and this code can be deleted.

A side effect of this change is that repositories will now raise an
error on encountering an ellipsis flag when the narrow extension is
loaded. Previously, loading the narrow extension on a non-narrow repo
could result in silent usage of the ellipsis flag. This could lead
to undetected bugs. I think the new behavior is more correct.

Differential Revision: https://phab.mercurial-scm.org/D4649

hgext/narrow/TODO.rst

@@ -1,30 +1,23 b''
 Integration with the share extension needs improvement. Right now
 we've seen some odd bugs, and the way we modify the contents of the
 .hg/shared file is unfortunate. See wrappostshare() and unsharenarrowspec().
 
 Resolve commentary on narrowrepo.wraprepo.narrowrepository.status
 about the filtering of status being done at an awkward layer. This
 came up the import to hgext, but nobody's got concrete improvement
 ideas as of then.
 
-Fold most (or preferably all) of narrowrevlog.py into core.
-
-Address commentary in narrowrevlog.excludedmanifestrevlog.add -
+Address commentary in manifest.excludedmanifestrevlog.add -
 specifically we should improve the collaboration with core so that
 add() never gets called on an excluded directory and we can improve
 the stand-in to raise a ProgrammingError.
 
-Figure out how to correctly produce narrowmanifestrevlog and
-narrowfilelog instances instead of monkeypatching regular revlogs at
-runtime to our subclass. Even better, merge the narrowing logic
-directly into core.
-
 Reason more completely about rename-filtering logic in
 narrowfilelog. There could be some surprises lurking there.
 
 Formally document the narrowspec format. Unify with sparse, if at all
 possible. For bonus points, unify with the server-specified narrowspec
 format.
 
 narrowrepo.setnarrowpats() or narrowspec.save() need to make sure
 they're holding the wlock.

hgext/narrow/__init__.py

@@ -1,88 +1,86 b''
 # __init__.py - narrowhg extension
 #
 # Copyright 2017 Google, Inc.
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 '''create clones which fetch history data for subset of files (EXPERIMENTAL)'''
 
 from __future__ import absolute_import
 
 # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
 # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
 # be specifying the version(s) of Mercurial they are tested with, or
 # leave the attribute unspecified.
 testedwith = 'ships-with-hg-core'
 
 from mercurial import (
     extensions,
     localrepo,
     registrar,
     repository,
     verify as verifymod,
 )
 
 from . import (
     narrowbundle2,
     narrowcommands,
     narrowcopies,
     narrowpatch,
     narrowrepo,
-    narrowrevlog,
     narrowtemplates,
     narrowwirepeer,
 )
 
 configtable = {}
 configitem = registrar.configitem(configtable)
 # Narrowhg *has* support for serving ellipsis nodes (which are used at
 # least by Google's internal server), but that support is pretty
 # fragile and has a lot of problems on real-world repositories that
 # have complex graph topologies. This could probably be corrected, but
 # absent someone needing the full support for ellipsis nodes in
 # repositories with merges, it's unlikely this work will get done. As
 # of this writining in late 2017, all repositories large enough for
 # ellipsis nodes to be a hard requirement also enforce strictly linear
 # history for other scaling reasons.
 configitem('experimental', 'narrowservebrokenellipses',
            default=False,
            alias=[('narrow', 'serveellipses')],
 )
 
 # Export the commands table for Mercurial to see.
 cmdtable = narrowcommands.table
 
 def featuresetup(ui, features):
     features.add(repository.NARROW_REQUIREMENT)
 
 def uisetup(ui):
     """Wraps user-facing mercurial commands with narrow-aware versions."""
     localrepo.featuresetupfuncs.add(featuresetup)
-    narrowrevlog.setup()
     narrowbundle2.setup()
     narrowcommands.setup()
     narrowwirepeer.uisetup()
 
 def reposetup(ui, repo):
     """Wraps local repositories with narrow repo support."""
     if not repo.local():
         return
 
     if repository.NARROW_REQUIREMENT in repo.requirements:
         narrowrepo.wraprepo(repo)
         narrowcopies.setup(repo)
         narrowpatch.setup(repo)
         narrowwirepeer.reposetup(repo)
 
 def _verifierinit(orig, self, repo, matcher=None):
     # The verifier's matcher argument was desgined for narrowhg, so it should
     # be None from core. If another extension passes a matcher (unlikely),
     # we'll have to fail until matchers can be composed more easily.
     assert matcher is None
     orig(self, repo, repo.narrowmatch())
 
 def extsetup(ui):
     extensions.wrapfunction(verifymod.verifier, '__init__', _verifierinit)
 
 templatekeyword = narrowtemplates.templatekeyword
 revsetpredicate = narrowtemplates.revsetpredicate