basefilectx: move _filenode from filectx

mercurial/context.py

@@ -432,6 +432,13 b' class basefilectx(object):'
         else:
             return self._filelog.linkrev(self._filerev)
 
+    @propertycache
+    def _filenode(self):
+        if '_fileid' in self.__dict__:
+            return self._filelog.lookup(self._fileid)
+        else:
+            return self._changectx.filenode(self._path)
+
 class filectx(basefilectx):
     """A filecontext object makes access to data related to a particular
        filerevision convenient."""
@@ -482,13 +489,6 b' class filectx(basefilectx):'
             return changectx(self._repo.unfiltered(), self._changeid)
 
     @propertycache
-    def _filenode(self):
-        if '_fileid' in self.__dict__:
-            return self._filelog.lookup(self._fileid)
-        else:
-            return self._changectx.filenode(self._path)
-
-    @propertycache
     def _filerev(self):
         return self._filelog.rev(self._filenode)