From fe0f574e20962325fd25508ee492737593b55c35 Mon Sep 17 00:00:00 2001 From: Serhiy Storchaka Date: Wed, 17 Oct 2018 20:57:29 +0300 Subject: [PATCH 1/2] bpo-32892: Support subclasses of base types in isinstance checks for AST constants. Some projects (e.g. Chameleon) create ast.Str containing an instance of the str subclass. --- Lib/ast.py | 2 +- Lib/test/test_ast.py | 3 +++ 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/Lib/ast.py b/Lib/ast.py index de3df1473e5ea21..4c8c7795ff822c1 100644 --- a/Lib/ast.py +++ b/Lib/ast.py @@ -346,7 +346,7 @@ def __instancecheck__(cls, inst): except AttributeError: return False else: - return type(value) in _const_types[cls] + return isinstance(value, _const_types[cls]) return type.__instancecheck__(cls, inst) def _new(cls, *args, **kwargs): diff --git a/Lib/test/test_ast.py b/Lib/test/test_ast.py index 10be02eee0c03c4..a3ffed74ae5bdcf 100644 --- a/Lib/test/test_ast.py +++ b/Lib/test/test_ast.py @@ -399,6 +399,9 @@ def test_isinstance(self): self.assertFalse(isinstance(ast.Constant(), ast.NameConstant)) self.assertFalse(isinstance(ast.Constant(), ast.Ellipsis)) + class S(str): pass + self.assertTrue(isinstance(ast.Constant(S('42')), ast.Str)) + def test_subclasses(self): class N(ast.Num): def __init__(self, *args, **kwargs): From cfe45afa0422285c6d5c5e578c0dcdfa102da4d5 Mon Sep 17 00:00:00 2001 From: Serhiy Storchaka Date: Fri, 26 Oct 2018 08:05:08 +0300 Subject: [PATCH 2/2] Add yet one test. --- Lib/test/test_ast.py | 1 + 1 file changed, 1 insertion(+) diff --git a/Lib/test/test_ast.py b/Lib/test/test_ast.py index a3ffed74ae5bdcf..4bbdc3b82daa527 100644 --- a/Lib/test/test_ast.py +++ b/Lib/test/test_ast.py @@ -401,6 +401,7 @@ def test_isinstance(self): class S(str): pass self.assertTrue(isinstance(ast.Constant(S('42')), ast.Str)) + self.assertFalse(isinstance(ast.Constant(S('42')), ast.Num)) def test_subclasses(self): class N(ast.Num):