@@ 880,33 880,29 @@ def choose_prodcomponent(ui, repo, cache
 
 
 class LazyDict(collections.abc.Mapping):
+    '''Dictionary that calls the given loader function when its contents are accessed.'''
     def __init__(self, loader):
         collections.abc.Mapping.__init__(self)
         self._loader = loader
         self._data = None
 
-    def __missing__(self, key):
-        if self._data is None:
-            self._data = self._loader()
-        return self._data.__getitem__(key)
-
-    def __getitem__(self, key):
+    def data(self):
         if self._data is None:
             self._data = self._loader()
-        return self._data.__getitem__(key)
+        return self._data
+
+    def __getitem__(self, key):
+        return self.data().__getitem__(key)
 
     def __iter__(self):
-        if self._data is None:
-            self._data = self._loader()
-        return self._data.__iter__()
+        return self.data().__iter__()
 
     def __len__(self):
-        if self._data is None:
-            self._data = self._loader()
-        return len(self._data)
+        return len(self.data())
 
 
 def fill_values(values, ui, repo, api_server, finalize=False, patchdata=None):
+    # If things are fully specified, the bugzilla configuration info may be unneeded.
     cache = LazyDict(lambda: bzauth.load_configuration(ui, api_server, BINARY_CACHE_FILENAME))
 
     if 'PRODUCT' in values: