Add theano flag on_shape_error.

NEWS.txt

@@ -164,6 +164,7 @@ Others:
  * Filtering update. (James)
  * The buidbot now raises optimization errors instead of just printing a warning. (Frederic)
  * On Windows, the default compiledir changed to be local to the computer/user and not transferred with roaming profile. (Sebastian Urban)
+ * New theano flag "on_shape_error". Default to "warn" (same as previous behavior): it print a warning when an error occur when infering the shape of some apply node. The other accepted value is "raise" to raise an error when this happen.
 
 Reviewers (alphabetical order):
  * David, Frederic, Ian, James, Olivier, Razvan

doc/library/config.txt

@@ -243,6 +243,16 @@ import theano and print the config variable, as in:
     the user and skip this optimization ('warn'), or raise the exception
     ('raise').
 
+.. attribute:: on_shape_error
+
+    String value: 'warn' or 'raise'
+
+    Default: 'warn'
+
+    When an exception is raised when infering the shape of some apply
+    node, either warn the user and use a default value ('warn'), or
+    raise the exception ('raise').
+
 .. attribute:: config.warn.ignore_bug_before
 
     String value: 'None', 'all', '0.3', '0.4', '0.4.1', '0.5'

theano/tensor/opt.py

@@ -34,6 +34,12 @@ from theano.gof import toolbox, DestroyHandler
 from basic import get_constant_value, ShapeError
 
 
+theano.configparser.AddConfigVar('on_shape_error',
+                                 "warn: print a warning and use the default"
+                                 " value. raise: raise an error",
+                                 theano.configparser.EnumStr("warn", "raise"),
+        in_c_key=False)
+
 # Utilities
 
 
@@ -906,11 +912,15 @@ class ShapeFeature(object):
                     'supported, and one should now use tensor.ShapeError '
                     'instead. The original exception message is: %s' % e)
         except Exception, e:
-            _logger.error(('Failed to infer_shape from Op %s.\nInput shapes:'
-                           '%s\nException encountered during infer_shape: '
-                           '%s\nException message: %s\nTraceback: %s') %
-                          (node.op, [self.shape_of[r] for r in node.inputs],
-                           type(e), str(e), traceback.format_exc()))
+            msg = ('Failed to infer_shape from Op %s.\nInput shapes:'
+                   '%s\nException encountered during infer_shape: '
+                   '%s\nException message: %s\nTraceback: %s') % (
+                node.op, [self.shape_of[r] for r in node.inputs],
+                type(e), str(e), traceback.format_exc())
+            if config.on_shape_error == "raise":
+                raise Exception(msg)
+            else:
+                _logger.error(msg)
             o_shapes = self.default_infer_shape(
                 node, [self.shape_of[r] for r in node.inputs])