Make UnboundLocalError message same as in CPython

Cython/Compiler/Code.py

@@ -1419,6 +1419,13 @@ class CCodeWriter(object):
 #        return self.putln("if (unlikely(%s < 0)) %s" % (value, self.error_goto(pos)))  # TODO this path is almost _never_ taken, yet this macro makes is slower!
         return self.putln("if (%s < 0) %s" % (value, self.error_goto(pos)))
 
+    def put_error_if_unbound(self, pos, entry):
+        self.put('if (unlikely(!%s)) { '
+                 'PyErr_SetString(PyExc_UnboundLocalError, "'
+                 "local variable '%s' referenced before assignment"
+                 '"); %s }' %
+                 (entry.cname, entry.name, self.error_goto(pos)))
+
     def set_error_info(self, pos):
         self.funcstate.should_declare_error_indicator = True
         if self.c_line_in_traceback:

Cython/Compiler/ExprNodes.py

@@ -1558,9 +1558,9 @@ class NameNode(AtomicExprNode):
 
         elif entry.is_local or entry.in_closure or entry.from_closure:
             if entry.type.is_pyobject:
-                if (self.cf_maybe_null or self.cf_is_null) and not self.allow_null:
-                    code.putln('if (unlikely(!%s)) { PyErr_SetString(PyExc_UnboundLocalError, "%s"); %s }' %
-                               (entry.cname, entry.name, code.error_goto(self.pos)))
+                if (self.cf_maybe_null or self.cf_is_null) \
+                       and not self.allow_null:
+                    code.put_error_if_unbound(self.pos, entry)
 
     def generate_assignment_code(self, rhs, code):
         #print "NameNode.generate_assignment_code:", self.name ###
@@ -1693,8 +1693,7 @@ class NameNode(AtomicExprNode):
         elif self.entry.type.is_pyobject:
             if not self.cf_is_null:
                 if self.cf_maybe_null:
-                    code.putln('if (unlikely(!%s)) { PyErr_SetString(PyExc_UnboundLocalError, "%s"); %s }' %
-                               (self.entry.cname, self.entry.name, code.error_goto(self.pos)))
+                    code.put_error_if_unbound(self.pos, self.entry)
                 code.put_decref(self.result(), self.ctype())
                 code.putln('%s = NULL;' % self.result())
         else:

tests/run/uninitialized.pyx

@@ -8,7 +8,7 @@ def conditional(cond):
     >>> conditional(False)
     Traceback (most recent call last):
     ...
-    UnboundLocalError: a
+    UnboundLocalError: local variable 'a' referenced before assignment
     """
     if cond:
         a = []
@@ -21,7 +21,7 @@ def inside_loop(iter):
     >>> inside_loop([])
     Traceback (most recent call last):
     ...
-    UnboundLocalError: i
+    UnboundLocalError: local variable 'i' referenced before assignment
     """
     for i in iter:
         pass
@@ -34,7 +34,7 @@ def try_except(cond):
     >>> try_except(False)
     Traceback (most recent call last):
     ...
-    UnboundLocalError: a
+    UnboundLocalError: local variable 'a' referenced before assignment
     """
     try:
         if cond:
@@ -50,7 +50,7 @@ def try_finally(cond):
     >>> try_finally(False)
     Traceback (most recent call last):
     ...
-    UnboundLocalError: a
+    UnboundLocalError: local variable 'a' referenced before assignment
     """
     try:
         if cond:
@@ -66,7 +66,7 @@ def deleted(cond):
     >>> deleted(True)
     Traceback (most recent call last):
     ...
-    UnboundLocalError: a
+    UnboundLocalError: local variable 'a' referenced before assignment
     """
     a = {}
     if cond:
@@ -80,7 +80,7 @@ def test_nested(cond):
     >>> test_nested(False)
     Traceback (most recent call last):
     ...
-    UnboundLocalError: a
+    UnboundLocalError: local variable 'a' referenced before assignment
     """
     if cond:
         def a():
@@ -94,7 +94,7 @@ def test_outer(cond):
     >>> test_outer(False)
     Traceback (most recent call last):
     ...
-    UnboundLocalError: a
+    UnboundLocalError: local variable 'a' referenced before assignment
     """
     if cond:
         a = {}
@@ -109,7 +109,7 @@ def test_inner(cond):
     >>> test_inner(False)
     Traceback (most recent call last):
     ...
-    UnboundLocalError: a
+    UnboundLocalError: local variable 'a' referenced before assignment
     """
     if cond:
         a = {}
@@ -124,7 +124,7 @@ def test_class(cond):
     >>> test_class(False)
     Traceback (most recent call last):
     ...
-    UnboundLocalError: A
+    UnboundLocalError: local variable 'A' referenced before assignment
     """
     if cond:
         class A: