repoview: define filteredchangelog as a top-level (non-local) class

As suggested by Greg. This makes it easier for extensions to override
the filtering.

Differential Revision: https://phab.mercurial-scm.org/D7256

mercurial/repoview.py

@@ -227,7 +227,14 b' def wrapchangelog(unfichangelog, filtere'
     cl = copy.copy(unfichangelog)
     cl.filteredrevs = filteredrevs
 
-    class filteredchangelog(cl.__class__):
+    cl.__class__ = type(
+        'filteredchangelog', (filteredchangelogmixin, cl.__class__), {}
+    )
+
+    return cl
+
+
+class filteredchangelogmixin(object):
         def tiprev(self):
             """filtered version of revlog.tiprev"""
             for i in pycompat.xrange(len(self) - 1, -2, -1):
@@ -250,7 +257,7 b' def wrapchangelog(unfichangelog, filtere'
 
         def revs(self, start=0, stop=None):
             """filtered version of revlog.revs"""
-            for i in super(filteredchangelog, self).revs(start, stop):
+        for i in super(filteredchangelogmixin, self).revs(start, stop):
                 if i not in self.filteredrevs:
                     yield i
 
@@ -285,17 +292,17 b' def wrapchangelog(unfichangelog, filtere'
                     return self._headrevs()
 
             revs = self._checknofilteredinrevs(revs)
-            return super(filteredchangelog, self).headrevs(revs)
+        return super(filteredchangelogmixin, self).headrevs(revs)
 
         def strip(self, *args, **kwargs):
             # XXX make something better than assert
             # We can't expect proper strip behavior if we are filtered.
             assert not self.filteredrevs
-            super(filteredchangelog, self).strip(*args, **kwargs)
+        super(filteredchangelogmixin, self).strip(*args, **kwargs)
 
         def rev(self, node):
             """filtered version of revlog.rev"""
-            r = super(filteredchangelog, self).rev(node)
+        r = super(filteredchangelogmixin, self).rev(node)
             if r in self.filteredrevs:
                 raise error.FilteredLookupError(
                     hex(node), self.indexfile, _(b'filtered node')
@@ -306,29 +313,25 b' def wrapchangelog(unfichangelog, filtere'
             """filtered version of revlog.node"""
             if rev in self.filteredrevs:
                 raise error.FilteredIndexError(rev)
-            return super(filteredchangelog, self).node(rev)
+        return super(filteredchangelogmixin, self).node(rev)
 
         def linkrev(self, rev):
             """filtered version of revlog.linkrev"""
             if rev in self.filteredrevs:
                 raise error.FilteredIndexError(rev)
-            return super(filteredchangelog, self).linkrev(rev)
+        return super(filteredchangelogmixin, self).linkrev(rev)
 
         def parentrevs(self, rev):
             """filtered version of revlog.parentrevs"""
             if rev in self.filteredrevs:
                 raise error.FilteredIndexError(rev)
-            return super(filteredchangelog, self).parentrevs(rev)
+        return super(filteredchangelogmixin, self).parentrevs(rev)
 
         def flags(self, rev):
             """filtered version of revlog.flags"""
             if rev in self.filteredrevs:
                 raise error.FilteredIndexError(rev)
-            return super(filteredchangelog, self).flags(rev)
-
-    cl.__class__ = filteredchangelog
-
-    return cl
+        return super(filteredchangelogmixin, self).flags(rev)
 
 
 class repoview(object):