gh-113570: reprlib.repr does not use builtin __repr__ for reshadowed builtins

Lib/reprlib.py

@@ -36,6 +36,17 @@ def wrapper(self):
     return decorating_function
 
 class Repr:
+    _lookup = {
+        "repr_tuple": ("builtins", "tuple"),
+        "repr_list": ("builtins", "list"),
+        "repr_array": ("array", "array"),
+        "repr_set": ("builtins", "set"),
+        "repr_frozenset": ("builtins", "frozenset"),
+        "repr_deque": ("collections", "deque"),
+        "repr_dict": ("builtins", "dict"),
+        "repr_str": ("builtins", "str"),
+        "repr_int": ("builtins", "int"),
+        }
 
     def __init__(
         self, *, maxlevel=6, maxtuple=6, maxlist=6, maxarray=5, maxdict=4,
@@ -60,15 +71,33 @@ def repr(self, x):
         return self.repr1(x, self.maxlevel)
 
     def repr1(self, x, level):
-        typename = type(x).__name__
-        if ' ' in typename:
+        _type = type(x)
+        typename = _type.__name__
+
+        if " " in typename:
             parts = typename.split()
-            typename = '_'.join(parts)
-        if hasattr(self, 'repr_' + typename):
-            return getattr(self, 'repr_' + typename)(x, level)
-        else:
+            typename = "_".join(parts)
+
+        method_name = "repr_" + typename
+
+        if not hasattr(self, method_name):
             return self.repr_instance(x, level)
 
+        # we have a predefined method for this type,
+        # but it has been set in a subclass
+        if method_name not in self._lookup:
+            return getattr(self, method_name)(x, level)
+
+        module = getattr(_type, "__module__", None)
+        is_shadowed = (module, typename) != self._lookup[method_name]
+
+        if is_shadowed:
+            # we have a predefined method for a class with
+            # the same name as x, but it is not x
+            return self.repr_instance(x, level)
+
+        return getattr(self, method_name)(x, level)
+
     def _join(self, pieces, level):
         if self.indent is None:
             return ', '.join(pieces)

Lib/test/test_reprlib.py

@@ -580,6 +580,42 @@ def test_invalid_indent(self):
                 with self.assertRaisesRegex(expected_error, expected_msg):
                     r.repr(test_object)
 
+    def test_shadowed_builtin(self):
+        # Issue #113570: repr() should not be fooled by a shadowed builtin
+        # function
+        class array:
+            def __repr__(self):
+                return "not array.array"
+
+        self.assertEqual(r(array()), "not array.array")
+
+    def test_custom_repr(self):
+        class MyRepr(Repr):
+
+            def repr_TextIOWrapper(self, obj, level):
+                if obj.name in {'<stdin>', '<stdout>', '<stderr>'}:
+                    return obj.name
+                return repr(obj)
+
+        aRepr = MyRepr()
+        self.assertEqual(aRepr.repr(sys.stdin), "<stdin>")
+
+    def test_custom_repr_class_with_spaces(self):
+        class TypeWithSpaces:
+            pass
+
+        t = TypeWithSpaces()
+        type(t).__name__ = "type with spaces"
+        self.assertEqual(type(t).__name__, "type with spaces")
+
+        class MyRepr(Repr):
+            def repr_type_with_spaces(self, obj, level):
+                return "Type With Spaces"
+
+
+        aRepr = MyRepr()
+        self.assertEqual(aRepr.repr(t), "Type With Spaces")
+
 def write_file(path, text):
     with open(path, 'w', encoding='ASCII') as fp:
         fp.write(text)

Misc/NEWS.d/next/Core and Builtins/2023-12-30-00-21-45.gh-issue-113570._XQgsW.rst

@@ -0,0 +1 @@
+Fixed a bug in ``reprlib.repr`` where it incorrectly called the repr method on shadowed Python built-in types.