Deactivate merge of assert as it cause cycle in the graph

theano/gof/opt.py

@@ -575,7 +575,8 @@ class MergeFeature(object):
                                 if c in self.nodes_seen]
 
             # Put all clients of Assert inputs (if exist) into merge_candidates
-            for i in node.inputs:
+            # TODO: Deactivated for now as this cause cycle in the graph.
+            for i in []:  # node.inputs:
                 if i.owner and isinstance(i.owner.op,
                                           theano.tensor.opt.Assert):
                     node_has_assert = True

theano/gof/tests/test_opt.py

@@ -362,7 +362,7 @@ class TestMergeOptimizer:
         strg = str(g)
         assert strg == '[Op1(y, y)]' or strg == '[Op1(z, z)]'
 
-    def test_one_assert_merge(self):
+    def est_one_assert_merge(self):
         # Merge two nodes, one has assert, the other not.
         x1 = T.matrix('x1')
         x2 = T.matrix('x2')
@@ -383,7 +383,7 @@ class TestMergeOptimizer:
 '''
         assert strg == strref, (strg, strref)
 
-    def test_both_assert_merge_1(self):
+    def est_both_assert_merge_1(self):
         # Merge two nodes, both have assert on the same node
         # with different conditions.
         x1 = T.matrix('x1')
@@ -427,7 +427,7 @@ class TestMergeOptimizer:
         # print(strg)
         assert strg == strref1 or strg == strref2, (strg, strref1, strref2)
 
-    def test_both_assert_merge_2(self):
+    def est_both_assert_merge_2(self):
         # Merge two nodes, both have assert on different node
         x1 = T.matrix('x1')
         x2 = T.matrix('x2')
@@ -456,7 +456,7 @@ class TestMergeOptimizer:
         # print(strg)
         assert strg == strref, (strg, strref)
 
-    def test_both_assert_merge_2_reverse(self):
+    def est_both_assert_merge_2_reverse(self):
         # Test case "test_both_assert_merge_2" but in reverse order
         x1 = T.matrix('x1')
         x2 = T.matrix('x2')