De-optimise the unicode methods ".upper()", ".lower()" and ".title()" on...

De-optimise the unicode methods ".upper()", ".lower()" and ".title()" on single character values since they must still be able to return multiple characters.

CHANGES.rst

@@ -20,6 +20,11 @@ Features added
 Bugs fixed
 ----------
 
+* The unicode methods ``.upper()``, ``.lower()`` and ``.title()`` were
+  incorrectly optimised for single character input values and only returned
+  the first character if multiple characters should have been returned.
+  They now use the original Python methods again.
+
 * The ``Py_hash_t`` type failed to accept arbitrary "index" values.
   (Github issue #2752)
 

Cython/Compiler/Optimize.py

@@ -3374,6 +3374,8 @@ class OptimizeBuiltinCalls(Visitor.NodeRefCleanupMixin,
             PyrexTypes.CFuncTypeArg("uchar", PyrexTypes.c_py_ucs4_type, None),
             ])
 
+    # DISABLED: Return value can only be one character, which is not correct.
+    '''
     def _inject_unicode_character_conversion(self, node, function, args, is_unbound_method):
         if is_unbound_method or len(args) != 1:
             return node
@@ -3392,9 +3394,10 @@ class OptimizeBuiltinCalls(Visitor.NodeRefCleanupMixin,
             func_call = func_call.coerce_to_pyobject(self.current_env)
         return func_call
 
-    _handle_simple_method_unicode_lower = _inject_unicode_character_conversion
-    _handle_simple_method_unicode_upper = _inject_unicode_character_conversion
-    _handle_simple_method_unicode_title = _inject_unicode_character_conversion
+    #_handle_simple_method_unicode_lower = _inject_unicode_character_conversion
+    #_handle_simple_method_unicode_upper = _inject_unicode_character_conversion
+    #_handle_simple_method_unicode_title = _inject_unicode_character_conversion
+    '''
 
     PyUnicode_Splitlines_func_type = PyrexTypes.CFuncType(
         Builtin.list_type, [

tests/run/py_ucs4_type.pyx

@@ -132,15 +132,24 @@ def unicode_type_methods(Py_UCS4 uchar):
         uchar.isupper(),
         ]
 
-@cython.test_assert_path_exists('//PythonCapiCallNode')
-@cython.test_fail_if_path_exists('//SimpleCallNode')
+#@cython.test_assert_path_exists('//PythonCapiCallNode')
+#@cython.test_fail_if_path_exists('//SimpleCallNode')
 def unicode_methods(Py_UCS4 uchar):
     """
-    >>> unicode_methods(ord('A')) == ['a', 'A', 'A']
+    >>> unicode_methods(ord('A')) == ['a', 'A', 'A'] or unicode_methods(ord('A'))
+    True
+    >>> unicode_methods(ord('a')) == ['a', 'A', 'A'] or unicode_methods(ord('a'))
     True
-    >>> unicode_methods(ord('a')) == ['a', 'A', 'A']
+    >>> unicode_methods(0x1E9E) == [u'\\xdf', u'\\u1e9e', u'\\u1e9e'] or unicode_methods(0x1E9E)
+    True
+    >>> unicode_methods(0x0130) in (
+    ...     [u'i\\u0307', u'\\u0130', u'\\u0130'],  # Py3
+    ...     [u'i', u'\\u0130', u'\\u0130'],  # Py2
+    ... ) or unicode_methods(0x0130)
     True
     """
+    # \u1E9E == 'LATIN CAPITAL LETTER SHARP S'
+    # \u0130 == 'LATIN CAPITAL LETTER I WITH DOT ABOVE'
     return [
         # character conversion
         uchar.lower(),
@@ -149,11 +158,11 @@ def unicode_methods(Py_UCS4 uchar):
         ]
 
 
-@cython.test_assert_path_exists('//PythonCapiCallNode')
-@cython.test_fail_if_path_exists(
-    '//SimpleCallNode',
-    '//CoerceFromPyTypeNode',
-)
+#@cython.test_assert_path_exists('//PythonCapiCallNode')
+#@cython.test_fail_if_path_exists(
+#    '//SimpleCallNode',
+#    '//CoerceFromPyTypeNode',
+#)
 def unicode_method_return_type(Py_UCS4 uchar):
     """
     >>> unicode_method_return_type(ord('A'))
@@ -366,5 +375,5 @@ def uchar_lookup_in_dict(obj, Py_UCS4 uchar):
 
 
 _WARNINGS = """
-364:16: Item lookup of unicode character codes now always converts to a Unicode string. Use an explicit C integer cast to get back the previous integer lookup behaviour.
+373:16: Item lookup of unicode character codes now always converts to a Unicode string. Use an explicit C integer cast to get back the previous integer lookup behaviour.
 """

tests/run/py_unicode_type.pyx

@@ -123,8 +123,8 @@ def unicode_type_methods(Py_UNICODE uchar):
         uchar.isupper(),
         ]
 
-@cython.test_assert_path_exists('//PythonCapiCallNode')
-@cython.test_fail_if_path_exists('//SimpleCallNode')
+#@cython.test_assert_path_exists('//PythonCapiCallNode')
+#@cython.test_fail_if_path_exists('//SimpleCallNode')
 def unicode_methods(Py_UNICODE uchar):
     """
     >>> unicode_methods(ord('A')) == ['a', 'A', 'A']