changegroup: inline prune() logic from narrow

changegroup: inline prune() logic from narrow

prune() needs to ellide manifests that aren't part of the narrow
matcher.

The code is violating storage abstractions, so a comment has been
added. Keep in mind the impetus for moving this code to core
is so changegroup code can be refactored to be storage agnostic.

Differential Revision: https://phab.mercurial-scm.org/D4012

--- a/hgext/narrow/narrowchangegroup.py	Sun Jul 22 15:50:45 2018 +0900
+++ b/hgext/narrow/narrowchangegroup.py	Sat Jul 28 14:52:46 2018 -0700
@@ -12,7 +12,6 @@
     changegroup,
     error,
     extensions,
-    manifest,
     mdiff,
     node,
     pycompat,
@@ -21,15 +20,6 @@
 )
 
 def setup():
-    def prune(orig, self, revlog, missing, commonrevs):
-        if isinstance(revlog, manifest.manifestrevlog):
-            if not self._filematcher.visitdir(revlog._dir[:-1] or '.'):
-                return []
-
-        return orig(self, revlog, missing, commonrevs)
-
-    extensions.wrapfunction(changegroup.cg1packer, 'prune', prune)
-
     def generatefiles(orig, self, changedfiles, linknodes, commonrevs,
                       source):
         changedfiles = list(filter(self._filematcher, changedfiles))

--- a/mercurial/changegroup.py	Sun Jul 22 15:50:45 2018 +0900
+++ b/mercurial/changegroup.py	Sat Jul 28 14:52:46 2018 -0700
@@ -21,6 +21,7 @@
 from . import (
     dagutil,
     error,
+    manifest,
     match as matchmod,
     mdiff,
     phases,
@@ -589,6 +590,11 @@
 
     # filter any nodes that claim to be part of the known set
     def prune(self, revlog, missing, commonrevs):
+        # TODO this violates storage abstraction for manifests.
+        if isinstance(revlog, manifest.manifestrevlog):
+            if not self._filematcher.visitdir(revlog._dir[:-1] or '.'):
+                return []
+
         rr, rl = revlog.rev, revlog.linkrev
         return [n for n in missing if rl(rr(n)) not in commonrevs]