py3: source-transform only call-sites of iteritems(), not definitions

py3: source-transform only call-sites of iteritems(), not definitions

branchmap.branchcache, among other classes, defines a
iteritems(). That currently gets replaced by items() by the source
transformer. That makes it harder for extensions to work with both py2
and py3, since they have to call either items() or iteritems() on
branchcache. Let's not replace definitions of iteritems() (and
itervalues()) and only replace the call-sites. We need to also add an
items() alias to branchcache (etc) so our transformer call-sites will
find it.

Differential Revision: https://phab.mercurial-scm.org/D6641

--- a/hgext/remotenames.py	Sun Jul 14 23:21:28 2019 -0700
+++ b/hgext/remotenames.py	Fri Jul 12 23:34:24 2019 -0700
@@ -167,6 +167,8 @@
         for k, vtup in self.potentialentries.iteritems():
             yield (k, [bin(vtup[0])])
 
+    items = iteritems
+
 class remotenames(object):
     """
     This class encapsulates all the remotenames state. It also contains

--- a/mercurial/__init__.py	Sun Jul 14 23:21:28 2019 -0700
+++ b/mercurial/__init__.py	Fri Jul 12 23:34:24 2019 -0700
@@ -225,7 +225,9 @@
 
                 # It changes iteritems/values to items/values as they are not
                 # present in Python 3 world.
-                elif fn in ('iteritems', 'itervalues'):
+                elif (fn in ('iteritems', 'itervalues') and
+                      not (tokens[i - 1].type == token.NAME and
+                           tokens[i - 1].string == 'def')):
                     yield t._replace(string=fn[4:])
                     continue
 
@@ -236,7 +238,7 @@
     # ``replacetoken`` or any mechanism that changes semantics of module
     # loading is changed. Otherwise cached bytecode may get loaded without
     # the new transformation mechanisms applied.
-    BYTECODEHEADER = b'HG\x00\x0b'
+    BYTECODEHEADER = b'HG\x00\x0c'
 
     class hgloader(importlib.machinery.SourceFileLoader):
         """Custom module loader that transforms source code.

--- a/mercurial/branchmap.py	Sun Jul 14 23:21:28 2019 -0700
+++ b/mercurial/branchmap.py	Fri Jul 12 23:34:24 2019 -0700
@@ -218,6 +218,8 @@
             self._verifybranch(k)
             yield k, v
 
+    items = iteritems
+
     def hasbranch(self, label):
         """ checks whether a branch of this name exists or not """
         self._verifybranch(label)