[Python-checkins] cpython (2.7): Issue #26906: Resolving special methods of uninitialized type now causes

Sat Oct 8 05:28:51 EDT 2016

https://hg.python.org/cpython/rev/3119f08802a5
changeset: 104366:3119f08802a5
branch: 2.7
parent: 104364:4ed5f0e9bba2
user: Serhiy Storchaka <storchaka at gmail.com>
date: Sat Oct 08 12:24:09 2016 +0300
summary:
 Issue #26906: Resolving special methods of uninitialized type now causes
implicit initialization of the type instead of a fail.
files:
 Misc/NEWS | 3 +++
 Objects/typeobject.c | 24 +++++++++++++++++++-----
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,9 @@
 Core and Builtins
 -----------------
 
+- Issue #26906: Resolving special methods of uninitialized type now causes
+ implicit initialization of the type instead of a fail.
+
 - Issue #18287: PyType_Ready() now checks that tp_name is not NULL.
 Original patch by Niklas Koep.
 
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -2545,11 +2545,25 @@
 /* Look in tp_dict of types in MRO */
 mro = type->tp_mro;
 
- /* If mro is NULL, the type is either not yet initialized
- by PyType_Ready(), or already cleared by type_clear().
- Either way the safest thing to do is to return NULL. */
- if (mro == NULL)
- return NULL;
+ if (mro == NULL) {
+ if ((type->tp_flags & Py_TPFLAGS_READYING) == 0 &&
+ PyType_Ready(type) < 0) {
+ /* It's not ideal to clear the error condition,
+ but this function is documented as not setting
+ an exception, and I don't want to change that.
+ When PyType_Ready() can't proceed, it won't
+ set the "ready" flag, so future attempts to ready
+ the same type will call it again -- hopefully
+ in a context that propagates the exception out.
+ */
+ PyErr_Clear();
+ return NULL;
+ }
+ mro = type->tp_mro;
+ if (mro == NULL) {
+ return NULL;
+ }
+ }
 
 res = NULL;
 assert(PyTuple_Check(mro));
-- 
Repository URL: https://hg.python.org/cpython
