lfs: register the flag processors per repository

Previously, enabling the extension for any repo in commandserver or hgweb would
enable the flags on all repos.  Since localrepo.resolverevlogstorevfsoptions()
is called so early, the check to see if the extension is enabled on the repo
(which hasn't been instantiated yet) is a bit awkward.  But I don't see a better
way.

hgext/lfs/__init__.py

@@ -1,401 +1,416
 # lfs - hash-preserving large file support using Git-LFS protocol
 #
 # Copyright 2017 Facebook, Inc.
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 """lfs - large file support (EXPERIMENTAL)
 
 This extension allows large files to be tracked outside of the normal
 repository storage and stored on a centralized server, similar to the
 ``largefiles`` extension.  The ``git-lfs`` protocol is used when
 communicating with the server, so existing git infrastructure can be
 harnessed.  Even though the files are stored outside of the repository,
 they are still integrity checked in the same manner as normal files.
 
 The files stored outside of the repository are downloaded on demand,
 which reduces the time to clone, and possibly the local disk usage.
 This changes fundamental workflows in a DVCS, so careful thought
 should be given before deploying it.  :hg:`convert` can be used to
 convert LFS repositories to normal repositories that no longer
 require this extension, and do so without changing the commit hashes.
 This allows the extension to be disabled if the centralized workflow
 becomes burdensome.  However, the pre and post convert clones will
 not be able to communicate with each other unless the extension is
 enabled on both.
 
 To start a new repository, or to add LFS files to an existing one, just
 create an ``.hglfs`` file as described below in the root directory of
 the repository.  Typically, this file should be put under version
 control, so that the settings will propagate to other repositories with
 push and pull.  During any commit, Mercurial will consult this file to
 determine if an added or modified file should be stored externally.  The
 type of storage depends on the characteristics of the file at each
 commit.  A file that is near a size threshold may switch back and forth
 between LFS and normal storage, as needed.
 
 Alternately, both normal repositories and largefile controlled
 repositories can be converted to LFS by using :hg:`convert` and the
 ``lfs.track`` config option described below.  The ``.hglfs`` file
 should then be created and added, to control subsequent LFS selection.
 The hashes are also unchanged in this case.  The LFS and non-LFS
 repositories can be distinguished because the LFS repository will
 abort any command if this extension is disabled.
 
 Committed LFS files are held locally, until the repository is pushed.
 Prior to pushing the normal repository data, the LFS files that are
 tracked by the outgoing commits are automatically uploaded to the
 configured central server.  No LFS files are transferred on
 :hg:`pull` or :hg:`clone`.  Instead, the files are downloaded on
 demand as they need to be read, if a cached copy cannot be found
 locally.  Both committing and downloading an LFS file will link the
 file to a usercache, to speed up future access.  See the `usercache`
 config setting described below.
 
 .hglfs::
 
     The extension reads its configuration from a versioned ``.hglfs``
     configuration file found in the root of the working directory. The
     ``.hglfs`` file uses the same syntax as all other Mercurial
     configuration files. It uses a single section, ``[track]``.
 
     The ``[track]`` section specifies which files are stored as LFS (or
     not). Each line is keyed by a file pattern, with a predicate value.
     The first file pattern match is used, so put more specific patterns
     first.  The available predicates are ``all()``, ``none()``, and
     ``size()``. See "hg help filesets.size" for the latter.
 
     Example versioned ``.hglfs`` file::
 
       [track]
       # No Makefile or python file, anywhere, will be LFS
       **Makefile = none()
       **.py = none()
 
       **.zip = all()
       **.exe = size(">1MB")
 
       # Catchall for everything not matched above
       ** = size(">10MB")
 
 Configs::
 
     [lfs]
     # Remote endpoint. Multiple protocols are supported:
     # - http(s)://user:[e-mail]/path
     #   git-lfs endpoint
     # - file:///tmp/path
     #   local filesystem, usually for testing
     # if unset, lfs will assume the remote repository also handles blob storage
     # for http(s) URLs.  Otherwise, lfs will prompt to set this when it must
     # use this value.
     # (default: unset)
     url = https://example.com/repo.git/info/lfs
 
     # Which files to track in LFS.  Path tests are "**.extname" for file
     # extensions, and "path:under/some/directory" for path prefix.  Both
     # are relative to the repository root.
     # File size can be tested with the "size()" fileset, and tests can be
     # joined with fileset operators.  (See "hg help filesets.operators".)
     #
     # Some examples:
     # - all()                       # everything
     # - none()                      # nothing
     # - size(">20MB")               # larger than 20MB
     # - !**.txt                     # anything not a *.txt file
     # - **.zip | **.tar.gz | **.7z  # some types of compressed files
     # - path:bin                    # files under "bin" in the project root
     # - (**.php & size(">2MB")) | (**.js & size(">5MB")) | **.tar.gz
     #     | (path:bin & !path:/bin/README) | size(">1GB")
     # (default: none())
     #
     # This is ignored if there is a tracked '.hglfs' file, and this setting
     # will eventually be deprecated and removed.
     track = size(">10M")
 
     # how many times to retry before giving up on transferring an object
     retry = 5
 
     # the local directory to store lfs files for sharing across local clones.
     # If not set, the cache is located in an OS specific cache location.
     usercache = /path/to/global/cache
 """
 
 from __future__ import absolute_import
 
+import sys
+
 from mercurial.i18n import _
 
 from mercurial import (
     bundle2,
     changegroup,
     cmdutil,
     config,
     context,
     error,
     exchange,
     extensions,
     filelog,
     filesetlang,
     localrepo,
     minifileset,
     node,
     pycompat,
     registrar,
     repository,
     revlog,
     scmutil,
     templateutil,
     upgrade,
     util,
     vfs as vfsmod,
     wireprotoserver,
     wireprotov1server,
 )
 
 from . import (
     blobstore,
     wireprotolfsserver,
     wrapper,
 )
 
 # 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'
 
 configtable = {}
 configitem = registrar.configitem(configtable)
 
 configitem('experimental', 'lfs.serve',
     default=True,
 )
 configitem('experimental', 'lfs.user-agent',
     default=None,
 )
 configitem('experimental', 'lfs.disableusercache',
     default=False,
 )
 configitem('experimental', 'lfs.worker-enable',
     default=False,
 )
 
 configitem('lfs', 'url',
     default=None,
 )
 configitem('lfs', 'usercache',
     default=None,
 )
 # Deprecated
 configitem('lfs', 'threshold',
     default=None,
 )
 configitem('lfs', 'track',
     default='none()',
 )
 configitem('lfs', 'retry',
     default=5,
 )
 
 cmdtable = {}
 command = registrar.command(cmdtable)
 
 templatekeyword = registrar.templatekeyword()
 filesetpredicate = registrar.filesetpredicate()
 
+lfsprocessor = (
+    wrapper.readfromstore,
+    wrapper.writetostore,
+    wrapper.bypasscheckhash,
+)
+
 def featuresetup(ui, supported):
     # don't die on seeing a repo with the lfs requirement
     supported |= {'lfs'}
 
 def uisetup(ui):
     localrepo.featuresetupfuncs.add(featuresetup)
 
 def reposetup(ui, repo):
     # Nothing to do with a remote repo
     if not repo.local():
         return
 
     repo.svfs.lfslocalblobstore = blobstore.local(repo)
     repo.svfs.lfsremoteblobstore = blobstore.remote(repo)
 
     class lfsrepo(repo.__class__):
         @localrepo.unfilteredmethod
         def commitctx(self, ctx, error=False):
             repo.svfs.options['lfstrack'] = _trackedmatcher(self)
             return super(lfsrepo, self).commitctx(ctx, error)
 
     repo.__class__ = lfsrepo
 
     if 'lfs' not in repo.requirements:
         def checkrequireslfs(ui, repo, **kwargs):
             if 'lfs' not in repo.requirements:
                 last = kwargs.get(r'node_last')
                 _bin = node.bin
                 if last:
                     s = repo.set('%n:%n', _bin(kwargs[r'node']), _bin(last))
                 else:
                     s = repo.set('%n', _bin(kwargs[r'node']))
             match = repo.narrowmatch()
             for ctx in s:
                 # TODO: is there a way to just walk the files in the commit?
                 if any(ctx[f].islfs() for f in ctx.files()
                        if f in ctx and match(f)):
                     repo.requirements.add('lfs')
                     repo.features.add(repository.REPO_FEATURE_LFS)
                     repo._writerequirements()
                     repo.prepushoutgoinghooks.add('lfs', wrapper.prepush)
                     break
 
         ui.setconfig('hooks', 'commit.lfs', checkrequireslfs, 'lfs')
         ui.setconfig('hooks', 'pretxnchangegroup.lfs', checkrequireslfs, 'lfs')
     else:
         repo.prepushoutgoinghooks.add('lfs', wrapper.prepush)
 
 def _trackedmatcher(repo):
     """Return a function (path, size) -> bool indicating whether or not to
     track a given file with lfs."""
     if not repo.wvfs.exists('.hglfs'):
         # No '.hglfs' in wdir.  Fallback to config for now.
         trackspec = repo.ui.config('lfs', 'track')
 
         # deprecated config: lfs.threshold
         threshold = repo.ui.configbytes('lfs', 'threshold')
         if threshold:
             filesetlang.parse(trackspec)  # make sure syntax errors are confined
             trackspec = "(%s) | size('>%d')" % (trackspec, threshold)
 
         return minifileset.compile(trackspec)
 
     data = repo.wvfs.tryread('.hglfs')
     if not data:
         return lambda p, s: False
 
     # Parse errors here will abort with a message that points to the .hglfs file
     # and line number.
     cfg = config.config()
     cfg.parse('.hglfs', data)
 
     try:
         rules = [(minifileset.compile(pattern), minifileset.compile(rule))
                  for pattern, rule in cfg.items('track')]
     except error.ParseError as e:
         # The original exception gives no indicator that the error is in the
         # .hglfs file, so add that.
 
         # TODO: See if the line number of the file can be made available.
         raise error.Abort(_('parse error in .hglfs: %s') % e)
 
     def _match(path, size):
         for pat, rule in rules:
             if pat(path, size):
                 return rule(path, size)
 
         return False
 
     return _match
 
 def wrapfilelog(filelog):
     wrapfunction = extensions.wrapfunction
 
     wrapfunction(filelog, 'addrevision', wrapper.filelogaddrevision)
     wrapfunction(filelog, 'renamed', wrapper.filelogrenamed)
     wrapfunction(filelog, 'size', wrapper.filelogsize)
 
+def _resolverevlogstorevfsoptions(orig, ui, requirements, features):
+    opts = orig(ui, requirements, features)
+    for name, module in extensions.extensions(ui):
+        if module is sys.modules[__name__]:
+            if revlog.REVIDX_EXTSTORED in opts[b'flagprocessors']:
+                msg = (_(b"cannot register multiple processors on flag '%#x'.")
+                       % revlog.REVIDX_EXTSTORED)
+                raise error.Abort(msg)
+
+            opts[b'flagprocessors'][revlog.REVIDX_EXTSTORED] = lfsprocessor
+            break
+
+    return opts
+
 def extsetup(ui):
     wrapfilelog(filelog.filelog)
 
     wrapfunction = extensions.wrapfunction
 
     wrapfunction(localrepo, 'makefilestorage', wrapper.localrepomakefilestorage)
+    wrapfunction(localrepo, 'resolverevlogstorevfsoptions',
+                 _resolverevlogstorevfsoptions)
 
     wrapfunction(cmdutil, '_updatecatformatter', wrapper._updatecatformatter)
     wrapfunction(scmutil, 'wrapconvertsink', wrapper.convertsink)
 
     wrapfunction(upgrade, '_finishdatamigration',
                  wrapper.upgradefinishdatamigration)
 
     wrapfunction(upgrade, 'preservedrequirements',
                  wrapper.upgraderequirements)
 
     wrapfunction(upgrade, 'supporteddestrequirements',
                  wrapper.upgraderequirements)
 
     wrapfunction(changegroup,
                  'allsupportedversions',
                  wrapper.allsupportedversions)
 
     wrapfunction(exchange, 'push', wrapper.push)
     wrapfunction(wireprotov1server, '_capabilities', wrapper._capabilities)
     wrapfunction(wireprotoserver, 'handlewsgirequest',
                  wireprotolfsserver.handlewsgirequest)
 
     wrapfunction(context.basefilectx, 'cmp', wrapper.filectxcmp)
     wrapfunction(context.basefilectx, 'isbinary', wrapper.filectxisbinary)
     context.basefilectx.islfs = wrapper.filectxislfs
 
-    revlog.addflagprocessor(
-        revlog.REVIDX_EXTSTORED,
-        (
-            wrapper.readfromstore,
-            wrapper.writetostore,
-            wrapper.bypasscheckhash,
-        ),
-    )
-
     scmutil.fileprefetchhooks.add('lfs', wrapper._prefetchfiles)
 
     # Make bundle choose changegroup3 instead of changegroup2. This affects
     # "hg bundle" command. Note: it does not cover all bundle formats like
     # "packed1". Using "packed1" with lfs will likely cause trouble.
     exchange._bundlespeccontentopts["v2"]["cg.version"] = "03"
 
     # bundlerepo uses "vfsmod.readonlyvfs(othervfs)", we need to make sure lfs
     # options and blob stores are passed from othervfs to the new readonlyvfs.
     wrapfunction(vfsmod.readonlyvfs, '__init__', wrapper.vfsinit)
 
     # when writing a bundle via "hg bundle" command, upload related LFS blobs
     wrapfunction(bundle2, 'writenewbundle', wrapper.writenewbundle)
 
 @filesetpredicate('lfs()')
 def lfsfileset(mctx, x):
     """File that uses LFS storage."""
     # i18n: "lfs" is a keyword
     filesetlang.getargs(x, 0, 0, _("lfs takes no arguments"))
     ctx = mctx.ctx
     def lfsfilep(f):
         return wrapper.pointerfromctx(ctx, f, removed=True) is not None
     return mctx.predicate(lfsfilep, predrepr='<lfs>')
 
 @templatekeyword('lfs_files', requires={'ctx'})
 def lfsfiles(context, mapping):
     """List of strings. All files modified, added, or removed by this
     changeset."""
     ctx = context.resource(mapping, 'ctx')
 
     pointers = wrapper.pointersfromctx(ctx, removed=True) # {path: pointer}
     files = sorted(pointers.keys())
 
     def pointer(v):
         # In the file spec, version is first and the other keys are sorted.
         sortkeyfunc = lambda x: (x[0] != 'version', x)
         items = sorted(pointers[v].iteritems(), key=sortkeyfunc)
         return util.sortdict(items)
 
     makemap = lambda v: {
         'file': v,
         'lfsoid': pointers[v].oid() if pointers[v] else None,
         'lfspointer': templateutil.hybriddict(pointer(v)),
     }
 
     # TODO: make the separator ', '?
     f = templateutil._showcompatlist(context, mapping, 'lfs_file', files)
     return templateutil.hybrid(f, files, makemap, pycompat.identity)
 
 @command('debuglfsupload',
          [('r', 'rev', [], _('upload large files introduced by REV'))])
 def debuglfsupload(ui, repo, **opts):
     """upload lfs blobs added by the working copy parent or given revisions"""
     revs = opts.get(r'rev', [])
     pointers = wrapper.extractpointers(repo, scmutil.revrange(repo, revs))
     wrapper.uploadblobs(repo, pointers)

tests/test-lfs-serve.t

@@ -1,523 +1,644
 #testcases lfsremote-on lfsremote-off
 #require serve no-reposimplestore no-chg
 
 This test splits `hg serve` with and without using the extension into separate
 tests cases.  The tests are broken down as follows, where "LFS"/"No-LFS"
 indicates whether or not there are commits that use an LFS file, and "D"/"E"
 indicates whether or not the extension is loaded.  The "X" cases are not tested
 individually, because the lfs requirement causes the process to bail early if
 the extension is disabled.
 
 .                        Server
 .
 .                    No-LFS        LFS
 .            +----------------------------+
 .            |   ||  D  |  E  |  D  |  E  |
 .            |---++=======================|
 .  C         | D || N/A | #1  |  X  | #4  |
 .  l    No   +---++-----------------------|
 .  i    LFS  | E || #2  | #2  |  X  | #5  |
 .  e         +---++-----------------------|
 .  n         | D ||  X  |  X  |  X  |  X  |
 .  t    LFS  |---++-----------------------|
 .            | E || #3  | #3  |  X  | #6  |
 .            |---++-----------------------+
 
 make command server magic visible
 
 #if windows
   $ PYTHONPATH="$TESTDIR/../contrib;$PYTHONPATH"
 #else
   $ PYTHONPATH="$TESTDIR/../contrib:$PYTHONPATH"
 #endif
   $ export PYTHONPATH
 
   $ hg init server
   $ SERVER_REQUIRES="$TESTTMP/server/.hg/requires"
 
+  $ cat > $TESTTMP/debugprocessors.py <<EOF
+  > from mercurial import (
+  >     cmdutil,
+  >     commands,
+  >     pycompat,
+  >     registrar,
+  > )
+  > cmdtable = {}
+  > command = registrar.command(cmdtable)
+  > @command(b'debugprocessors', [], b'FILE')
+  > def debugprocessors(ui, repo, file_=None, **opts):
+  >     opts = pycompat.byteskwargs(opts)
+  >     opts[b'changelog'] = False
+  >     opts[b'manifest'] = False
+  >     opts[b'dir'] = False
+  >     rl = cmdutil.openrevlog(repo, b'debugprocessors', file_, opts)
+  >     for flag, proc in rl._flagprocessors.iteritems():
+  >         ui.status(b"registered processor '%#x'\n" % (flag))
+  > EOF
+
 Skip the experimental.changegroup3=True config.  Failure to agree on this comes
 first, and causes a "ValueError: no common changegroup version" or "abort:
 HTTP Error 500: Internal Server Error", if the extension is only loaded on one
 side.  If that *is* enabled, the subsequent failure is "abort: missing processor
 for flag '0x2000'!" if the extension is only loaded on one side (possibly also
 masked by the Internal Server Error message).
   $ cat >> $HGRCPATH <<EOF
+  > [extensions]
+  > debugprocessors = $TESTTMP/debugprocessors.py
   > [experimental]
   > lfs.disableusercache = True
   > [lfs]
   > threshold=10
   > [web]
   > allow_push=*
   > push_ssl=False
   > EOF
 
+  $ cp $HGRCPATH $HGRCPATH.orig
+
 #if lfsremote-on
   $ hg --config extensions.lfs= -R server \
   >    serve -p $HGPORT -d --pid-file=hg.pid --errorlog=$TESTTMP/errors.log
 #else
   $ hg --config extensions.lfs=! -R server \
   >    serve -p $HGPORT -d --pid-file=hg.pid --errorlog=$TESTTMP/errors.log
 #endif
 
   $ cat hg.pid >> $DAEMON_PIDS
   $ hg clone -q http://localhost:$HGPORT client
   $ grep 'lfs' client/.hg/requires $SERVER_REQUIRES
   [1]
 
 This trivial repo will force commandserver to load the extension, but not call
 reposetup() on another repo actually being operated on.  This gives coverage
 that wrapper functions are not assuming reposetup() was called.
 
   $ hg init $TESTTMP/cmdservelfs
   $ cat >> $TESTTMP/cmdservelfs/.hg/hgrc << EOF
   > [extensions]
   > lfs =
   > EOF
 
 --------------------------------------------------------------------------------
 Case #1: client with non-lfs content and the extension disabled; server with
 non-lfs content, and the extension enabled.
 
   $ cd client
   $ echo 'non-lfs' > nonlfs.txt
   >>> from __future__ import absolute_import
   >>> from hgclient import check, readchannel, runcommand
   >>> @check
   ... def diff(server):
   ...     readchannel(server)
   ...     # run an arbitrary command in the repo with the extension loaded
   ...     runcommand(server, ['id', '-R', '../cmdservelfs'])
   ...     # now run a command in a repo without the extension to ensure that
   ...     # files are added safely..
   ...     runcommand(server, ['ci', '-Aqm', 'non-lfs'])
   ...     # .. and that scmutil.prefetchfiles() safely no-ops..
   ...     runcommand(server, ['diff', '-r', '.~1'])
   ...     # .. and that debugupgraderepo safely no-ops.
   ...     runcommand(server, ['debugupgraderepo', '-q', '--run'])
   *** runcommand id -R ../cmdservelfs
   000000000000 tip
   *** runcommand ci -Aqm non-lfs
   *** runcommand diff -r .~1
   diff -r 000000000000 nonlfs.txt
   --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
   +++ b/nonlfs.txt	Thu Jan 01 00:00:00 1970 +0000
   @@ -0,0 +1,1 @@
   +non-lfs
   *** runcommand debugupgraderepo -q --run
   upgrade will perform the following actions:
   
   requirements
      preserved: dotencode, fncache, generaldelta, revlogv1, store
   
   beginning upgrade...
   repository locked and read-only
   creating temporary repository to stage migrated data: * (glob)
   (it is safe to interrupt this process any time before data migration completes)
   migrating 3 total revisions (1 in filelogs, 1 in manifests, 1 in changelog)
   migrating 324 bytes in store; 129 bytes tracked data
   migrating 1 filelogs containing 1 revisions (73 bytes in store; 8 bytes tracked data)
   finished migrating 1 filelog revisions across 1 filelogs; change in size: 0 bytes
   migrating 1 manifests containing 1 revisions (117 bytes in store; 52 bytes tracked data)
   finished migrating 1 manifest revisions across 1 manifests; change in size: 0 bytes
   migrating changelog containing 1 revisions (134 bytes in store; 69 bytes tracked data)
   finished migrating 1 changelog revisions; change in size: 0 bytes
   finished migrating 3 total revisions; total change in store size: 0 bytes
   copying phaseroots
   data fully migrated to temporary repository
   marking source repository as being upgraded; clients will be unable to read from repository
   starting in-place swap of repository data
   replaced files will be backed up at * (glob)
   replacing store...
   store replacement complete; repository was inconsistent for *s (glob)
   finalizing requirements file and making repository readable again
   removing temporary repository * (glob)
   copy of old repository backed up at * (glob)
   the old repository will not be deleted; remove it to free up disk space once the upgraded repository is verified
 
   $ grep 'lfs' .hg/requires $SERVER_REQUIRES
   [1]
 
 #if lfsremote-on
 
   $ hg push -q
   $ grep 'lfs' .hg/requires $SERVER_REQUIRES
   [1]
 
   $ hg clone -q http://localhost:$HGPORT $TESTTMP/client1_clone
   $ grep 'lfs' $TESTTMP/client1_clone/.hg/requires $SERVER_REQUIRES
   [1]
 
   $ hg init $TESTTMP/client1_pull
   $ hg -R $TESTTMP/client1_pull pull -q http://localhost:$HGPORT
   $ grep 'lfs' $TESTTMP/client1_pull/.hg/requires $SERVER_REQUIRES
   [1]
 
   $ hg identify http://localhost:$HGPORT
   d437e1d24fbd
 
 #endif
 
 --------------------------------------------------------------------------------
 Case #2: client with non-lfs content and the extension enabled; server with
 non-lfs content, and the extension state controlled by #testcases.
 
   $ cat >> $HGRCPATH <<EOF
   > [extensions]
   > lfs =
   > EOF
   $ echo 'non-lfs' > nonlfs2.txt
   $ hg ci -Aqm 'non-lfs file with lfs client'
 
 Since no lfs content has been added yet, the push is allowed, even when the
 extension is not enabled remotely.
 
   $ hg push -q
   $ grep 'lfs' .hg/requires $SERVER_REQUIRES
   [1]
 
   $ hg clone -q http://localhost:$HGPORT $TESTTMP/client2_clone
   $ grep 'lfs' $TESTTMP/client2_clone/.hg/requires $SERVER_REQUIRES
   [1]
 
   $ hg init $TESTTMP/client2_pull
   $ hg -R $TESTTMP/client2_pull pull -q http://localhost:$HGPORT
   $ grep 'lfs' $TESTTMP/client2_pull/.hg/requires $SERVER_REQUIRES
   [1]
 
   $ hg identify http://localhost:$HGPORT
   1477875038c6
 
 --------------------------------------------------------------------------------
 Case #3: client with lfs content and the extension enabled; server with
 non-lfs content, and the extension state controlled by #testcases.  The server
 should have an 'lfs' requirement after it picks up its first commit with a blob.
 
   $ echo 'this is a big lfs file' > lfs.bin
   $ hg ci -Aqm 'lfs'
   $ grep 'lfs' .hg/requires $SERVER_REQUIRES
   .hg/requires:lfs
 
 #if lfsremote-off
   $ hg push -q
   abort: required features are not supported in the destination: lfs
   (enable the lfs extension on the server)
   [255]
 #else
   $ hg push -q
 #endif
   $ grep 'lfs' .hg/requires $SERVER_REQUIRES
   .hg/requires:lfs
   $TESTTMP/server/.hg/requires:lfs (lfsremote-on !)
 
   $ hg clone -q http://localhost:$HGPORT $TESTTMP/client3_clone
   $ grep 'lfs' $TESTTMP/client3_clone/.hg/requires $SERVER_REQUIRES || true
   $TESTTMP/client3_clone/.hg/requires:lfs (lfsremote-on !)
   $TESTTMP/server/.hg/requires:lfs (lfsremote-on !)
 
   $ hg init $TESTTMP/client3_pull
   $ hg -R $TESTTMP/client3_pull pull -q http://localhost:$HGPORT
   $ grep 'lfs' $TESTTMP/client3_pull/.hg/requires $SERVER_REQUIRES || true
   $TESTTMP/client3_pull/.hg/requires:lfs (lfsremote-on !)
   $TESTTMP/server/.hg/requires:lfs (lfsremote-on !)
 
 The difference here is the push failed above when the extension isn't
 enabled on the server.
   $ hg identify http://localhost:$HGPORT
   8374dc4052cb (lfsremote-on !)
   1477875038c6 (lfsremote-off !)
 
 Don't bother testing the lfsremote-off cases- the server won't be able
 to launch if there's lfs content and the extension is disabled.
 
 #if lfsremote-on
 
 --------------------------------------------------------------------------------
 Case #4: client with non-lfs content and the extension disabled; server with
 lfs content, and the extension enabled.
 
   $ cat >> $HGRCPATH <<EOF
   > [extensions]
   > lfs = !
   > EOF
 
   $ hg init $TESTTMP/client4
   $ cd $TESTTMP/client4
   $ cat >> .hg/hgrc <<EOF
   > [paths]
   > default = http://localhost:$HGPORT
   > EOF
   $ echo 'non-lfs' > nonlfs2.txt
   $ hg ci -Aqm 'non-lfs'
   $ grep 'lfs' .hg/requires $SERVER_REQUIRES
   $TESTTMP/server/.hg/requires:lfs
 
   $ hg push -q --force
   warning: repository is unrelated
   $ grep 'lfs' .hg/requires $SERVER_REQUIRES
   $TESTTMP/server/.hg/requires:lfs
 
 TODO: fail more gracefully.
 
   $ hg clone -q http://localhost:$HGPORT $TESTTMP/client4_clone
   abort: HTTP Error 500: Internal Server Error
   [255]
   $ grep 'lfs' $TESTTMP/client4_clone/.hg/requires $SERVER_REQUIRES
   grep: $TESTTMP/client4_clone/.hg/requires: $ENOENT$
   $TESTTMP/server/.hg/requires:lfs
   [2]
 
 TODO: fail more gracefully.
 
   $ hg init $TESTTMP/client4_pull
   $ hg -R $TESTTMP/client4_pull pull -q http://localhost:$HGPORT
   abort: HTTP Error 500: Internal Server Error
   [255]
   $ grep 'lfs' $TESTTMP/client4_pull/.hg/requires $SERVER_REQUIRES
   $TESTTMP/server/.hg/requires:lfs
 
   $ hg identify http://localhost:$HGPORT
   03b080fa9d93
 
 --------------------------------------------------------------------------------
 Case #5: client with non-lfs content and the extension enabled; server with
 lfs content, and the extension enabled.
 
   $ cat >> $HGRCPATH <<EOF
   > [extensions]
   > lfs =
   > EOF
   $ echo 'non-lfs' > nonlfs3.txt
   $ hg ci -Aqm 'non-lfs file with lfs client'
 
   $ hg push -q
   $ grep 'lfs' .hg/requires $SERVER_REQUIRES
   $TESTTMP/server/.hg/requires:lfs
 
   $ hg clone -q http://localhost:$HGPORT $TESTTMP/client5_clone
   $ grep 'lfs' $TESTTMP/client5_clone/.hg/requires $SERVER_REQUIRES
   $TESTTMP/client5_clone/.hg/requires:lfs
   $TESTTMP/server/.hg/requires:lfs
 
   $ hg init $TESTTMP/client5_pull
   $ hg -R $TESTTMP/client5_pull pull -q http://localhost:$HGPORT
   $ grep 'lfs' $TESTTMP/client5_pull/.hg/requires $SERVER_REQUIRES
   $TESTTMP/client5_pull/.hg/requires:lfs
   $TESTTMP/server/.hg/requires:lfs
 
   $ hg identify http://localhost:$HGPORT
   c729025cc5e3
 
+  $ mv $HGRCPATH $HGRCPATH.tmp
+  $ cp $HGRCPATH.orig $HGRCPATH
+
+  >>> from __future__ import absolute_import
+  >>> from hgclient import check, readchannel, runcommand
+  >>> @check
+  ... def checkflags(server):
+  ...     readchannel(server)
+  ...     print('')
+  ...     print('# LFS required- both lfs and non-lfs revlogs have 0x2000 flag')
+  ...     runcommand(server, ['debugprocessors', 'lfs.bin', '-R',
+  ...                '../server'])
+  ...     runcommand(server, ['debugprocessors', 'nonlfs2.txt', '-R',
+  ...                '../server'])
+  ...     runcommand(server, ['config', 'extensions', '--cwd',
+  ...                '../server'])
+  ... 
+  ...     print("\n# LFS not enabled- revlogs don't have 0x2000 flag")
+  ...     runcommand(server, ['debugprocessors', 'nonlfs3.txt'])
+  ...     runcommand(server, ['config', 'extensions'])
+  
+  # LFS required- both lfs and non-lfs revlogs have 0x2000 flag
+  *** runcommand debugprocessors lfs.bin -R ../server
+  registered processor '0x8000'
+  registered processor '0x2000'
+  *** runcommand debugprocessors nonlfs2.txt -R ../server
+  registered processor '0x8000'
+  registered processor '0x2000'
+  *** runcommand config extensions --cwd ../server
+  extensions.debugprocessors=$TESTTMP/debugprocessors.py
+  extensions.lfs=
+  
+  # LFS not enabled- revlogs don't have 0x2000 flag
+  *** runcommand debugprocessors nonlfs3.txt
+  registered processor '0x8000'
+  *** runcommand config extensions
+  extensions.debugprocessors=$TESTTMP/debugprocessors.py
+
+  $ rm $HGRCPATH
+  $ mv $HGRCPATH.tmp $HGRCPATH
+
+  $ hg clone $TESTTMP/client $TESTTMP/nonlfs -qr 0 --config extensions.lfs=
+  $ cat >> $TESTTMP/nonlfs/.hg/hgrc <<EOF
+  > [extensions]
+  > lfs = !
+  > EOF
+
+  >>> from __future__ import absolute_import, print_function
+  >>> from hgclient import check, readchannel, runcommand
+  >>> @check
+  ... def checkflags2(server):
+  ...     readchannel(server)
+  ...     print('')
+  ...     print('# LFS enabled- both lfs and non-lfs revlogs have 0x2000 flag')
+  ...     runcommand(server, ['debugprocessors', 'lfs.bin', '-R',
+  ...                '../server'])
+  ...     runcommand(server, ['debugprocessors', 'nonlfs2.txt', '-R',
+  ...                '../server'])
+  ...     runcommand(server, ['config', 'extensions', '--cwd',
+  ...                '../server'])
+  ... 
+  ...     print('\n# LFS enabled without requirement- revlogs have 0x2000 flag')
+  ...     runcommand(server, ['debugprocessors', 'nonlfs3.txt'])
+  ...     runcommand(server, ['config', 'extensions'])
+  ... 
+  ...     print("\n# LFS disabled locally- revlogs don't have 0x2000 flag")
+  ...     runcommand(server, ['debugprocessors', 'nonlfs.txt', '-R',
+  ...                '../nonlfs'])
+  ...     runcommand(server, ['config', 'extensions', '--cwd',
+  ...                '../nonlfs'])
+  
+  # LFS enabled- both lfs and non-lfs revlogs have 0x2000 flag
+  *** runcommand debugprocessors lfs.bin -R ../server
+  registered processor '0x8000'
+  registered processor '0x2000'
+  *** runcommand debugprocessors nonlfs2.txt -R ../server
+  registered processor '0x8000'
+  registered processor '0x2000'
+  *** runcommand config extensions --cwd ../server
+  extensions.debugprocessors=$TESTTMP/debugprocessors.py
+  extensions.lfs=
+  
+  # LFS enabled without requirement- revlogs have 0x2000 flag
+  *** runcommand debugprocessors nonlfs3.txt
+  registered processor '0x8000'
+  registered processor '0x2000'
+  *** runcommand config extensions
+  extensions.debugprocessors=$TESTTMP/debugprocessors.py
+  extensions.lfs=
+  
+  # LFS disabled locally- revlogs don't have 0x2000 flag
+  *** runcommand debugprocessors nonlfs.txt -R ../nonlfs
+  registered processor '0x8000'
+  *** runcommand config extensions --cwd ../nonlfs
+  extensions.debugprocessors=$TESTTMP/debugprocessors.py
+  extensions.lfs=!
+
 --------------------------------------------------------------------------------
 Case #6: client with lfs content and the extension enabled; server with
 lfs content, and the extension enabled.
 
   $ echo 'this is another lfs file' > lfs2.txt
   $ hg ci -Aqm 'lfs file with lfs client'
 
   $ hg --config paths.default= push -v http://localhost:$HGPORT
   pushing to http://localhost:$HGPORT/
   lfs: assuming remote store: http://localhost:$HGPORT/.git/info/lfs
   searching for changes
   remote has heads on branch 'default' that are not known locally: 8374dc4052cb
   lfs: uploading a82f1c5cea0d40e3bb3a849686bb4e6ae47ca27e614de55c1ed0325698ef68de (25 bytes)
   lfs: processed: a82f1c5cea0d40e3bb3a849686bb4e6ae47ca27e614de55c1ed0325698ef68de
   lfs: uploaded 1 files (25 bytes)
   1 changesets found
   uncompressed size of bundle content:
        206 (changelog)
        172 (manifests)
        275  lfs2.txt
   remote: adding changesets
   remote: adding manifests
   remote: adding file changes
   remote: added 1 changesets with 1 changes to 1 files
   $ grep 'lfs' .hg/requires $SERVER_REQUIRES
   .hg/requires:lfs
   $TESTTMP/server/.hg/requires:lfs
 
   $ hg clone -q http://localhost:$HGPORT $TESTTMP/client6_clone
   $ grep 'lfs' $TESTTMP/client6_clone/.hg/requires $SERVER_REQUIRES
   $TESTTMP/client6_clone/.hg/requires:lfs
   $TESTTMP/server/.hg/requires:lfs
 
   $ hg init $TESTTMP/client6_pull
   $ hg -R $TESTTMP/client6_pull pull -u -v http://localhost:$HGPORT
   pulling from http://localhost:$HGPORT/
   requesting all changes
   adding changesets
   adding manifests
   adding file changes
   added 6 changesets with 5 changes to 5 files (+1 heads)
   calling hook pretxnchangegroup.lfs: hgext.lfs.checkrequireslfs
   new changesets d437e1d24fbd:d3b84d50eacb
   resolving manifests
   lfs: assuming remote store: http://localhost:$HGPORT/.git/info/lfs
   lfs: downloading a82f1c5cea0d40e3bb3a849686bb4e6ae47ca27e614de55c1ed0325698ef68de (25 bytes)
   lfs: processed: a82f1c5cea0d40e3bb3a849686bb4e6ae47ca27e614de55c1ed0325698ef68de
   lfs: downloaded 1 files (25 bytes)
   getting lfs2.txt
   lfs: found a82f1c5cea0d40e3bb3a849686bb4e6ae47ca27e614de55c1ed0325698ef68de in the local lfs store
   getting nonlfs2.txt
   getting nonlfs3.txt
   3 files updated, 0 files merged, 0 files removed, 0 files unresolved
   updated to "d3b84d50eacb: lfs file with lfs client"
   1 other heads for branch "default"
   (sent 3 HTTP requests and * bytes; received * bytes in responses) (glob)
   $ grep 'lfs' $TESTTMP/client6_pull/.hg/requires $SERVER_REQUIRES
   $TESTTMP/client6_pull/.hg/requires:lfs
   $TESTTMP/server/.hg/requires:lfs
 
   $ hg identify http://localhost:$HGPORT
   d3b84d50eacb
 
 --------------------------------------------------------------------------------
 Misc: process dies early if a requirement exists and the extension is disabled
 
   $ hg --config extensions.lfs=! summary
   abort: repository requires features unknown to this Mercurial: lfs!
   (see https://mercurial-scm.org/wiki/MissingRequirement for more information)
   [255]
 
   $ echo 'this is an lfs file' > $TESTTMP/client6_clone/lfspair1.bin
   $ echo 'this is an lfs file too' > $TESTTMP/client6_clone/lfspair2.bin
   $ hg -R $TESTTMP/client6_clone ci -Aqm 'add lfs pair'
   $ hg -R $TESTTMP/client6_clone push -q
 
   $ hg clone -qU http://localhost:$HGPORT $TESTTMP/bulkfetch
 
 Export will prefetch all needed files across all needed revisions
 
   $ hg -R $TESTTMP/bulkfetch -v export -r 0:tip -o all.export
   lfs: assuming remote store: http://localhost:$HGPORT/.git/info/lfs
   exporting patches:
   lfs: assuming remote store: http://localhost:$HGPORT/.git/info/lfs
   lfs: need to transfer 4 objects (92 bytes)
   lfs: downloading a82f1c5cea0d40e3bb3a849686bb4e6ae47ca27e614de55c1ed0325698ef68de (25 bytes)
   lfs: processed: a82f1c5cea0d40e3bb3a849686bb4e6ae47ca27e614de55c1ed0325698ef68de
   lfs: downloading bed80f00180ac404b843628ab56a1c1984d6145c391cd1628a7dd7d2598d71fc (23 bytes)
   lfs: processed: bed80f00180ac404b843628ab56a1c1984d6145c391cd1628a7dd7d2598d71fc
   lfs: downloading cf1b2787b74e66547d931b6ebe28ff63303e803cb2baa14a8f57c4383d875782 (20 bytes)
   lfs: processed: cf1b2787b74e66547d931b6ebe28ff63303e803cb2baa14a8f57c4383d875782
   lfs: downloading d96eda2c74b56e95cfb5ffb66b6503e198cc6fc4a09dc877de925feebc65786e (24 bytes)
   lfs: processed: d96eda2c74b56e95cfb5ffb66b6503e198cc6fc4a09dc877de925feebc65786e
   lfs: downloaded 4 files (92 bytes)
   all.export
   lfs: found bed80f00180ac404b843628ab56a1c1984d6145c391cd1628a7dd7d2598d71fc in the local lfs store
   lfs: found a82f1c5cea0d40e3bb3a849686bb4e6ae47ca27e614de55c1ed0325698ef68de in the local lfs store
   lfs: found cf1b2787b74e66547d931b6ebe28ff63303e803cb2baa14a8f57c4383d875782 in the local lfs store
   lfs: found d96eda2c74b56e95cfb5ffb66b6503e198cc6fc4a09dc877de925feebc65786e in the local lfs store
 
 Export with selected files is used with `extdiff --patch`
 
   $ rm -r $TESTTMP/bulkfetch/.hg/store/lfs
   $ hg --config extensions.extdiff= \
   >    -R $TESTTMP/bulkfetch -v extdiff -r 2:tip --patch $TESTTMP/bulkfetch/lfs.bin
   lfs: assuming remote store: http://localhost:$HGPORT/.git/info/lfs
   lfs: assuming remote store: http://localhost:$HGPORT/.git/info/lfs
   lfs: downloading bed80f00180ac404b843628ab56a1c1984d6145c391cd1628a7dd7d2598d71fc (23 bytes)
   lfs: processed: bed80f00180ac404b843628ab56a1c1984d6145c391cd1628a7dd7d2598d71fc
   lfs: downloaded 1 files (23 bytes)
   */hg-8374dc4052cb.patch (glob)
   lfs: found bed80f00180ac404b843628ab56a1c1984d6145c391cd1628a7dd7d2598d71fc in the local lfs store
   */hg-9640b57e77b1.patch (glob)
   --- */hg-8374dc4052cb.patch	* (glob)
   +++ */hg-9640b57e77b1.patch	* (glob)
   @@ -2,12 +2,7 @@
    # User test
    # Date 0 0
    #      Thu Jan 01 00:00:00 1970 +0000
   -# Node ID 8374dc4052cbd388e79d9dc4ddb29784097aa354
   -# Parent  1477875038c60152e391238920a16381c627b487
   -lfs
   +# Node ID 9640b57e77b14c3a0144fb4478b6cc13e13ea0d1
   +# Parent  d3b84d50eacbd56638e11abce6b8616aaba54420
   +add lfs pair
    
   -diff -r 1477875038c6 -r 8374dc4052cb lfs.bin
   ---- /dev/null	Thu Jan 01 00:00:00 1970 +0000
   -+++ b/lfs.bin	Thu Jan 01 00:00:00 1970 +0000
   -@@ -0,0 +1,1 @@
   -+this is a big lfs file
   cleaning up temp directory
   [1]
 
 Diff will prefetch files
 
   $ rm -r $TESTTMP/bulkfetch/.hg/store/lfs
   $ hg -R $TESTTMP/bulkfetch -v diff -r 2:tip
   lfs: assuming remote store: http://localhost:$HGPORT/.git/info/lfs
   lfs: assuming remote store: http://localhost:$HGPORT/.git/info/lfs
   lfs: need to transfer 4 objects (92 bytes)
   lfs: downloading a82f1c5cea0d40e3bb3a849686bb4e6ae47ca27e614de55c1ed0325698ef68de (25 bytes)
   lfs: processed: a82f1c5cea0d40e3bb3a849686bb4e6ae47ca27e614de55c1ed0325698ef68de
   lfs: downloading bed80f00180ac404b843628ab56a1c1984d6145c391cd1628a7dd7d2598d71fc (23 bytes)
   lfs: processed: bed80f00180ac404b843628ab56a1c1984d6145c391cd1628a7dd7d2598d71fc
   lfs: downloading cf1b2787b74e66547d931b6ebe28ff63303e803cb2baa14a8f57c4383d875782 (20 bytes)
   lfs: processed: cf1b2787b74e66547d931b6ebe28ff63303e803cb2baa14a8f57c4383d875782
   lfs: downloading d96eda2c74b56e95cfb5ffb66b6503e198cc6fc4a09dc877de925feebc65786e (24 bytes)
   lfs: processed: d96eda2c74b56e95cfb5ffb66b6503e198cc6fc4a09dc877de925feebc65786e
   lfs: downloaded 4 files (92 bytes)
   lfs: found bed80f00180ac404b843628ab56a1c1984d6145c391cd1628a7dd7d2598d71fc in the local lfs store
   lfs: found a82f1c5cea0d40e3bb3a849686bb4e6ae47ca27e614de55c1ed0325698ef68de in the local lfs store
   lfs: found cf1b2787b74e66547d931b6ebe28ff63303e803cb2baa14a8f57c4383d875782 in the local lfs store
   lfs: found d96eda2c74b56e95cfb5ffb66b6503e198cc6fc4a09dc877de925feebc65786e in the local lfs store
   diff -r 8374dc4052cb -r 9640b57e77b1 lfs.bin
   --- a/lfs.bin	Thu Jan 01 00:00:00 1970 +0000
   +++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
   @@ -1,1 +0,0 @@
   -this is a big lfs file
   diff -r 8374dc4052cb -r 9640b57e77b1 lfs2.txt
   --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
   +++ b/lfs2.txt	Thu Jan 01 00:00:00 1970 +0000
   @@ -0,0 +1,1 @@
   +this is another lfs file
   diff -r 8374dc4052cb -r 9640b57e77b1 lfspair1.bin
   --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
   +++ b/lfspair1.bin	Thu Jan 01 00:00:00 1970 +0000
   @@ -0,0 +1,1 @@
   +this is an lfs file
   diff -r 8374dc4052cb -r 9640b57e77b1 lfspair2.bin
   --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
   +++ b/lfspair2.bin	Thu Jan 01 00:00:00 1970 +0000
   @@ -0,0 +1,1 @@
   +this is an lfs file too
   diff -r 8374dc4052cb -r 9640b57e77b1 nonlfs.txt
   --- a/nonlfs.txt	Thu Jan 01 00:00:00 1970 +0000
   +++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
   @@ -1,1 +0,0 @@
   -non-lfs
   diff -r 8374dc4052cb -r 9640b57e77b1 nonlfs3.txt
   --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
   +++ b/nonlfs3.txt	Thu Jan 01 00:00:00 1970 +0000
   @@ -0,0 +1,1 @@
   +non-lfs
 
 Only the files required by diff are prefetched
 
   $ rm -r $TESTTMP/bulkfetch/.hg/store/lfs
   $ hg -R $TESTTMP/bulkfetch -v diff -r 2:tip $TESTTMP/bulkfetch/lfspair2.bin
   lfs: assuming remote store: http://localhost:$HGPORT/.git/info/lfs
   lfs: assuming remote store: http://localhost:$HGPORT/.git/info/lfs
   lfs: downloading d96eda2c74b56e95cfb5ffb66b6503e198cc6fc4a09dc877de925feebc65786e (24 bytes)
   lfs: processed: d96eda2c74b56e95cfb5ffb66b6503e198cc6fc4a09dc877de925feebc65786e
   lfs: downloaded 1 files (24 bytes)
   lfs: found d96eda2c74b56e95cfb5ffb66b6503e198cc6fc4a09dc877de925feebc65786e in the local lfs store
   diff -r 8374dc4052cb -r 9640b57e77b1 lfspair2.bin
   --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
   +++ b/lfspair2.bin	Thu Jan 01 00:00:00 1970 +0000
   @@ -0,0 +1,1 @@
   +this is an lfs file too
 
 #endif
 
   $ "$PYTHON" $TESTDIR/killdaemons.py $DAEMON_PIDS
 
 #if lfsremote-on
   $ cat $TESTTMP/errors.log | grep '^[A-Z]'
   Traceback (most recent call last):
   ValueError: no common changegroup version
   Traceback (most recent call last):
   ValueError: no common changegroup version
 #else
   $ cat $TESTTMP/errors.log
 #endif