Merge pull request #4013 from Sentient07/issue-3573

theano/gof/toolbox.py

@@ -273,6 +273,8 @@ class ReplaceValidate(History, Validator):
             if hasattr(fgraph, attr):
                 raise AlreadyThere("ReplaceValidate feature is already present"
                                    " or in conflict with another plugin.")
+        self._nodes_removed = set()
+        self.fail_validate = False
         History.on_attach(self, fgraph)
         Validator.on_attach(self, fgraph)
         self.unpickle(fgraph)
@@ -289,6 +291,7 @@ class ReplaceValidate(History, Validator):
     def on_detach(self, fgraph):
         History.on_detach(self, fgraph)
         Validator.on_detach(self, fgraph)
+        del self._nodes_removed
         del fgraph.replace_validate
         del fgraph.replace_all_validate
         del fgraph.replace_all_validate_remove
@@ -347,6 +350,7 @@ class ReplaceValidate(History, Validator):
 
         """
         chk = fgraph.replace_all_validate(replacements, reason)
+        self._nodes_removed.update(remove)
         for rm in remove:
             if rm in fgraph.apply_nodes or rm in fgraph.variables:
                 fgraph.revert(chk)
@@ -369,6 +373,15 @@ class ReplaceValidate(History, Validator):
             del d["history"]
         return d
 
+    def on_import(self, fgraph, node, reason):
+        if node in self._nodes_removed:
+            self.fail_validate = True
+
+    def validate(self, fgraph):
+        if self.fail_validate:
+            self.fail_validate = False
+            raise theano.gof.InconsistencyError("Trying to reintroduce a removed node")
+
 
 class NodeFinder(Bookkeeper):