Add error_on_uninitialized option and disable it for pyregr testsuite

Cython/Compiler/FlowControl.py

@@ -9,6 +9,7 @@ cython.declare(PyrexTypes=object, ExprNodes=object, Nodes=object,
 import Builtin
 import ExprNodes
 import Nodes
+import Options
 from PyrexTypes import py_object_type, unspecified_type
 import PyrexTypes
 
@@ -574,7 +575,8 @@ def check_definitions(flow, compiler_directives):
             if node.allow_null or entry.from_closure or entry.is_pyclass_attr:
                 pass # Can be uninitialized here
             elif node.cf_is_null:
-                if (entry.type.is_pyobject or entry.type.is_unspecified or
+                if Options.error_on_uninitialized and (
+                        entry.type.is_pyobject or entry.type.is_unspecified or
                         entry.error_on_uninitialized):
                     messages.error(
                         node.pos,

Cython/Compiler/Options.py

@@ -34,6 +34,12 @@ warning_errors = False
 # you should disable this option and also 'cache_builtins'.
 error_on_unknown_names = True
 
+# Make uninitialized local variable reference a compile time error.
+# Python raises UnboundLocalError at runtime, whereas this option makes
+# them a compile time error. Note that this option affects only variables
+# of "python object" type.
+error_on_uninitialized = True
+
 # This will convert statements of the form "for i in range(...)"
 # to "for i from ..." when i is a cdef'd integer type, and the direction
 # (i.e. sign of step) can be determined.

runtests.py

@@ -520,7 +520,9 @@ class CythonCompileTestCase(unittest.TestCase):
     def setUp(self):
         from Cython.Compiler import Options
         self._saved_options = [ (name, getattr(Options, name))
-                                for name in ('warning_errors', 'error_on_unknown_names') ]
+                                for name in ('warning_errors',
+                                             'error_on_unknown_names',
+                                             'error_on_uninitialized') ]
         self._saved_default_directives = Options.directive_defaults.items()
         Options.warning_errors = self.warning_errors
 
@@ -989,6 +991,7 @@ class CythonPyregrTestCase(CythonRunTestCase):
         CythonRunTestCase.setUp(self)
         from Cython.Compiler import Options
         Options.error_on_unknown_names = False
+        Options.error_on_uninitialized = False
         Options.directive_defaults.update(dict(
             binding=True, always_allow_keywords=True,
             set_initial_path="SOURCEFILE"))