From d1bf0eeb0fb0c485da076075a15ffdfd5fb68303 Mon Sep 17 00:00:00 2001 From: David Lechner Date: Thu, 17 Nov 2022 14:15:46 -0600 Subject: [PATCH] tests/cpydiff: Add diff for overriding __init__. This adds a CPython diff that explains why calling `super().__init__()` is required in MicroPython when subclassing a native type (because `__new__` and `__init__` are not separate functions). Signed-off-by: David Lechner --- tests/cpydiff/core_class_super_init.py | 31 ++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) create mode 100644 tests/cpydiff/core_class_super_init.py diff --git a/tests/cpydiff/core_class_super_init.py b/tests/cpydiff/core_class_super_init.py new file mode 100644 index 0000000000..1774f61dd8 --- /dev/null +++ b/tests/cpydiff/core_class_super_init.py @@ -0,0 +1,31 @@ +""" +categories: Core,Classes +description: When inheriting native types, calling a method in ``__init__(self, ...)`` before ``super().__init__()`` raises an ``AttributeError`` (or segfaults if ``MICROPY_BUILTIN_METHOD_CHECK_SELF_ARG`` is not enabled). +cause: MicroPython does not have separate ``__new__`` and ``__init__`` methods in native types. +workaround: Call ``super().__init__()`` first. +""" + + +class L1(list): + def __init__(self, a): + self.append(a) + + +try: + L1(1) + print("OK") +except AttributeError: + print("AttributeError") + + +class L2(list): + def __init__(self, a): + super().__init__() + self.append(a) + + +try: + L2(1) + print("OK") +except AttributeError: + print("AttributeError")