infer_shape does not survive through all exceptions anymore, and now uses…

theano/tensor/opt.py

@@ -32,6 +32,12 @@ from basic import get_constant_value
 
 # Utilities
 
+
+class ShapeError(Exception):
+    """Raised when the shape cannot be computed."""
+    pass
+
+
 def out2in(*local_opts):
     """WRITEME """
     return opt.TopoOptimizer(opt.LocalOptGroup(*local_opts),
@@ -528,7 +534,7 @@ class ShapeFeature(object):
     the cost of many Ops accurately, and generate c-code that is specific [e.g. unrolled] to
     particular sizes.
 
-    If you can determine the shape only in some case, return NotImplementedError when you can't
+    In cases where you cannot figure out the shape, raise a ShapeError.
 
     .. note::
 
@@ -714,13 +720,22 @@ class ShapeFeature(object):
 
         try:
             o_shapes = shape_infer(node, [self.shape_of[r] for r in node.inputs])
-        except NotImplementedError:
+        except ShapeError:
             o_shapes = self.default_infer_shape(node, [self.shape_of[r] for r in node.inputs])
+        except NotImplementedError, e:
+            raise NotImplementedError(
+                    'Code called by infer_shape failed raising a '
+                    'NotImplementedError. Raising NotImplementedError to '
+                    'indicate that a shape cannot be computed is no longer '
+                    'supported, and one should now use tensor.opt.ShapeError '
+                    'instead. The original exception message is: %s' % e)
         except Exception, e:
             _logger.error('Failed to infer_shape from Op %s (i_shapes=%s): %s %s'% (node.op,
                 [self.shape_of[r] for r in node.inputs],
                 type(e), str(e)))
-            o_shapes = self.default_infer_shape(node, [self.shape_of[r] for r in node.inputs])
+            # We raise the exception to make sure the user knows something bad
+            # is going on.
+            raise
 
         # this is packed information
         # an element of o_shapes is either None or a tuple