keyword: make wrapped repository and kwtemplater refer to each other

Wrapper functions of keyword extension are defined in reposetup(),
because they refer to kwtemplater instantiated in reposetup().

But these functions can be defined statically, if kwtemplater can be
obtained via repository at runtime.

This is a part of preparations for defining them statically.

To avoid cyclic reference, this patch makes kwtemplater use weakref to
refer related repository instance.

hgext/keyword.py

@@ -88,6 +88,7 @@ from __future__ import absolute_import
 import os
 import re
 import tempfile
+import weakref
 
 from mercurial.i18n import _
 from mercurial.hgweb import webcommands
@@ -212,7 +213,7 @@ class kwtemplater(object):
 
     def __init__(self, ui, repo, inc, exc):
         self.ui = ui
-        self.repo = repo
+        self._repo = weakref.ref(repo)
         self.match = match.match(repo.root, '', [], inc, exc)
         self.restrict = kwtools['hgcmd'] in restricted.split()
         self.postcommit = False
@@ -223,6 +224,10 @@ class kwtemplater(object):
         else:
             self.templates = _defaultkwmaps(self.ui)
 
+    @property
+    def repo(self):
+        return self._repo()
+
     @util.propertycache
     def escape(self):
         '''Returns bar-separated and escaped keywords.'''
@@ -658,6 +663,9 @@ def reposetup(ui, repo):
                 finally:
                     kwt.restrict = origrestrict
 
+    repo.__class__ = kwrepo
+    repo._keywordkwt = kwt
+
     # monkeypatches
     def kwpatchfile_init(orig, self, ui, gp, backend, store, eolmode=None):
         '''Monkeypatch/wrap patch.patchfile.__init__ to avoid
@@ -768,4 +776,3 @@ def reposetup(ui, repo):
     extensions.wrapfunction(cmdutil, 'dorecord', kw_dorecord)
     for c in nokwwebcommands.split():
         extensions.wrapfunction(webcommands, c, kwweb_skip)
-    repo.__class__ = kwrepo