--- a/hgext/lfs/wireprotolfsserver.py	Thu May 24 21:54:31 2018 +0900
+++ b/hgext/lfs/wireprotolfsserver.py	Thu May 31 09:19:09 2018 -0400
@@ -18,6 +18,7 @@
 
 from mercurial import (
     pycompat,
+    util,
 )
 
 from . import blobstore
@@ -40,6 +41,9 @@
     if not rctx.repo.ui.configbool('experimental', 'lfs.serve'):
         return False
 
+    if not util.safehasattr(rctx.repo.svfs, 'lfslocalblobstore'):
+        return False
+
     if not req.dispatchpath:
         return False
 

--- a/hgext/lfs/wrapper.py	Thu May 24 21:54:31 2018 +0900
+++ b/hgext/lfs/wrapper.py	Thu May 31 09:19:09 2018 -0400
@@ -37,8 +37,9 @@
 def _capabilities(orig, repo, proto):
     '''Wrap server command to announce lfs server capability'''
     caps = orig(repo, proto)
-    # XXX: change to 'lfs=serve' when separate git server isn't required?
-    caps.append('lfs')
+    if util.safehasattr(repo.svfs, 'lfslocalblobstore'):
+        # XXX: change to 'lfs=serve' when separate git server isn't required?
+        caps.append('lfs')
     return caps
 
 def bypasscheckhash(self, text):
@@ -118,16 +119,18 @@
 def filelogaddrevision(orig, self, text, transaction, link, p1, p2,
                        cachedelta=None, node=None,
                        flags=revlog.REVIDX_DEFAULT_FLAGS, **kwds):
-    textlen = len(text)
-    # exclude hg rename meta from file size
-    meta, offset = revlog.parsemeta(text)
-    if offset:
-        textlen -= offset
+    # The matcher isn't available if reposetup() wasn't called.
+    lfstrack = self.opener.options.get('lfstrack')
 
-    lfstrack = self.opener.options['lfstrack']
+    if lfstrack:
+        textlen = len(text)
+        # exclude hg rename meta from file size
+        meta, offset = revlog.parsemeta(text)
+        if offset:
+            textlen -= offset
 
-    if lfstrack(self.filename, textlen):
-        flags |= revlog.REVIDX_EXTSTORED
+        if lfstrack(self.filename, textlen):
+            flags |= revlog.REVIDX_EXTSTORED
 
     return orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta,
                 node=node, flags=flags, **kwds)
@@ -247,6 +250,9 @@
 def _prefetchfiles(repo, revs, match):
     """Ensure that required LFS blobs are present, fetching them as a group if
     needed."""
+    if not util.safehasattr(repo.svfs, 'lfslocalblobstore'):
+        return
+
     pointers = []
     oids = set()
     localstore = repo.svfs.lfslocalblobstore
@@ -266,10 +272,18 @@
         blobstore.remote(repo).readbatch(pointers, localstore)
 
 def _canskipupload(repo):
+    # Skip if this hasn't been passed to reposetup()
+    if not util.safehasattr(repo.svfs, 'lfsremoteblobstore'):
+        return True
+
     # if remotestore is a null store, upload is a no-op and can be skipped
     return isinstance(repo.svfs.lfsremoteblobstore, blobstore._nullremote)
 
 def candownload(repo):
+    # Skip if this hasn't been passed to reposetup()
+    if not util.safehasattr(repo.svfs, 'lfsremoteblobstore'):
+        return False
+
     # if remotestore is a null store, downloads will lead to nothing
     return not isinstance(repo.svfs.lfsremoteblobstore, blobstore._nullremote)
 
@@ -389,13 +403,16 @@
 def upgradefinishdatamigration(orig, ui, srcrepo, dstrepo, requirements):
     orig(ui, srcrepo, dstrepo, requirements)
 
-    srclfsvfs = srcrepo.svfs.lfslocalblobstore.vfs
-    dstlfsvfs = dstrepo.svfs.lfslocalblobstore.vfs
+    # Skip if this hasn't been passed to reposetup()
+    if (util.safehasattr(srcrepo.svfs, 'lfslocalblobstore') and
+        util.safehasattr(dstrepo.svfs, 'lfslocalblobstore')):
+        srclfsvfs = srcrepo.svfs.lfslocalblobstore.vfs
+        dstlfsvfs = dstrepo.svfs.lfslocalblobstore.vfs
 
-    for dirpath, dirs, files in srclfsvfs.walk():
-        for oid in files:
-            ui.write(_('copying lfs blob %s\n') % oid)
-            lfutil.link(srclfsvfs.join(oid), dstlfsvfs.join(oid))
+        for dirpath, dirs, files in srclfsvfs.walk():
+            for oid in files:
+                ui.write(_('copying lfs blob %s\n') % oid)
+                lfutil.link(srclfsvfs.join(oid), dstlfsvfs.join(oid))
 
 def upgraderequirements(orig, repo):
     reqs = orig(repo)

--- a/tests/test-lfs-serve.t	Thu May 24 21:54:31 2018 +0900
+++ b/tests/test-lfs-serve.t	Thu May 31 09:19:09 2018 -0400
@@ -23,6 +23,15 @@
 .            | 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"
 
@@ -55,13 +64,76 @@
   $ 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
-  $ hg ci -Aqm 'non-lfs'
+  >>> 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 132 bytes in store; 129 bytes tracked data
+  migrating 1 filelogs containing 1 revisions (9 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 (53 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 (70 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]