Update on merged work for #4659

theano/gof/fg.py

@@ -53,7 +53,7 @@ class MissingInputError(Exception):
             # The call to list is needed for Python 3
             assert list(kwargs.keys()) == ["variable"]
             tr = getattr(list(kwargs.values())[0].tag, 'trace', [])
-            if type(tr) is list and len(tr) > 0:
+            if isinstance(tr, list) is list and len(tr) > 0:
                 sio = StringIO()
                 print("\nBacktrace when the variable is created:", file=sio)
                 for subtr in list(kwargs.values())[0].tag.trace:

theano/gof/link.py

@@ -179,7 +179,7 @@ def raise_with_op(node, thunk=None, exc_info=None, storage_map=None):
 
     # Print node backtraces
     tr = getattr(node.outputs[0].tag, 'trace', [])
-    if type(tr) is list and len(tr) > 0:
+    if isinstance(tr, list) is list and len(tr) > 0:
         detailed_err_msg += "\nBacktrace when the node is created(use Theano flag traceback.limit=N to make it longer):\n"
 
         # Print separate message for each element in the list of batcktraces

theano/gof/opt.py

@@ -3010,9 +3010,17 @@ def check_stack_trace(f_or_fgraph, ops_to_check='last', bug_print='raise'):
         else:
             raise ValueError('The string bug_print is not recognised')
 
+    print("apply_nodes_to_check")
+    print(apply_nodes_to_check)
     for node in apply_nodes_to_check:
         for output in node.outputs:
+            print('Checking node')
+            print (node)            
             if (not hasattr(output.tag, 'trace') or not output.tag.trace):
+                print ('Failed on node')
+                print (node)
+                #print(node.outputs[0].tag.trace)
+                #print(node.tag.trace)
                 return False
 
     return True

theano/tensor/opt.py

@@ -4226,7 +4226,7 @@ def local_flatten_lift(node):
         # Copy over stacktrace from previous output node and from unary
         # elementwise output node since if there was an error, it would
         # probably have come from that operation.
-        copy_stack_trace(node.outputs + node.inputs[0], e)
+        copy_stack_trace(node.outputs + node.inputs, e)
 
         return [e]
 
@@ -5186,7 +5186,7 @@ def local_sum_prod_mul_by_scalar(node):
                 ret = T.mul(*mul_inputs)
                 # Copy over stacktrace from previous output to new mul op,
                 # for same reason as above.
-                copy_stack_trace(node.outputs, ret+mul_inputs)
+                copy_stack_trace(node.outputs, [ret]+mul_inputs)
 
                 return [ret]
 
@@ -5196,7 +5196,7 @@ def local_sum_prod_mul_by_scalar(node):
             # There are never errors in the negative op, thus
             # we need only to copy over stacktrace from previous output node to
             # the two new ops.
-            copy_stack_trace(node.outputs, s+ret)
+            copy_stack_trace(node.outputs, [s, ret])
 
             return [ret]
 
@@ -5212,8 +5212,8 @@ def local_elemwise_sub_zeros(node):
             node.op.scalar_op == scalar.sub and
             node.inputs[0] == node.inputs[1]):
         res = T.zeros_like(node.inputs[0])
+
         # Copy over stacktrace from previous output.
-        # Julian: Pascal, is this really necessary? Is there anyway zeros_like can ever fail?
         copy_stack_trace(node.outputs, res)
         return [res]