basefilectx: move filerev from filectx

mercurial/context.py

@@ -477,6 +477,9 b' class basefilectx(object):'
     def __ne__(self, other):
         return not (self == other)
 
+    def filerev(self):
+        return self._filerev
+
 class filectx(basefilectx):
     """A filecontext object makes access to data related to a particular
        filerevision convenient."""
@@ -532,8 +535,6 b' class filectx(basefilectx):'
         return filectx(self._repo, self._path, fileid=fileid,
                        filelog=self._filelog)
 
-    def filerev(self):
-        return self._filerev
     def filenode(self):
         return self._filenode
     def flags(self):