Remove the optional reason argument to on_change_input.

theano/gof/destroyhandler.py

@@ -442,7 +442,7 @@ if 0:
 
             self.stale_droot = True
 
-        def on_change_input(self, fgraph, app, i, old_r, new_r):
+        def on_change_input(self, fgraph, app, i, old_r, new_r, reason):
             """app.inputs[i] changed from old_r to new_r """
             if app == 'output':
                 # app == 'output' is special key that means FunctionGraph is redefining which nodes are being
@@ -827,7 +827,7 @@ class DestroyHandler(toolbox.Bookkeeper):
 
         self.stale_droot = True
 
-    def on_change_input(self, fgraph, app, i, old_r, new_r):
+    def on_change_input(self, fgraph, app, i, old_r, new_r, reason):
         """app.inputs[i] changed from old_r to new_r """
         if app == 'output':
             # app == 'output' is special key that means FunctionGraph is redefining which nodes are being

theano/gof/fg.py

@@ -376,7 +376,7 @@ class FunctionGraph(utils.object2):
         current value of node.inputs[i] which we want to replace.
 
         For each feature that has a 'on_change_input' method, calls:
-          feature.on_change_input(function_graph, node, i, old_r, new_r, [reason])
+          feature.on_change_input(function_graph, node, i, old_r, new_r, reason)
         """
         # TODO: ERROR HANDLING FOR LISTENERS (should it complete the change or revert it?)
         if node == 'output':
@@ -512,14 +512,7 @@ class FunctionGraph(utils.object2):
                 # not existing
                 continue
 
-            #####HORRIBLE OPTIONAL ARGUMENT HACK
-            try:
-                fn(self, *args, **kwargs)
-            except TypeError, e:
-                if str(e) == "on_change_input() got an unexpected keyword argument 'reason'" and len(kwargs) == 1:
-                    fn(self, *args)
-                else:
-                    raise
+            fn(self, *args, **kwargs)
 
     def collect_callbacks(self, name, *args):
         """WRITEME

theano/gof/opt.py

@@ -423,7 +423,7 @@ class MergeFeature(object):
         for node in fgraph.toposort():
             self.on_import(fgraph, node, "on_attach")
 
-    def on_change_input(self, fgraph, node, i, r, new_r):
+    def on_change_input(self, fgraph, node, i, r, new_r, reason):
         # If inputs to node change, it is not guaranteed that it is distinct
         # from the other nodes in nodes_seen
         if node in self.nodes_seen:
@@ -1171,7 +1171,7 @@ class NavigatorOptimizer(Optimizer):
                 def on_prune(self, fgraph, node, reason):
                     pruner(node)
             if chin is not None:
-                def on_change_input(self, fgraph, node, i, r, new_r):
+                def on_change_input(self, fgraph, node, i, r, new_r, reason):
                     chin(node, i, r, new_r)
 
         u = Updater()
@@ -1360,7 +1360,7 @@ class ChangeTracker:
     def on_import(self, fgraph, node, reason):
         self.changed = True
 
-    def on_change_input(self, fgraph, node, i, r, new_r):
+    def on_change_input(self, fgraph, node, i, r, new_r, reason):
         self.changed = True
 
     def reset(self):

theano/sandbox/linalg/ops.py

@@ -159,7 +159,7 @@ class HintsFeature(object):
             if k not in new_hints:
                 new_hints[k] = v
 
-    def on_change_input(self, fgraph, node, i, r, new_r):
+    def on_change_input(self, fgraph, node, i, r, new_r, reason):
         # TODO:
         # This tells us that r and new_r must have the same shape
         # if we didn't know that the shapes are related, now we do.

theano/tensor/opt.py

@@ -1075,7 +1075,7 @@ class ShapeFeature(object):
         for r, s in izip(node.outputs, o_shapes):
             self.set_shape(r, s)
 
-    def on_change_input(self, fgraph, node, i, r, new_r):
+    def on_change_input(self, fgraph, node, i, r, new_r, reason):
         if new_r not in self.shape_of:
             # It happen that the fgraph didn't called on_import for some
             # new_r.  This happen when new_r don't have an