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As noted in the issue: https://bugs.python.org/issue15870#msg402800 `PyType_FromSpec` assumes that the `name` passed is persistent for the program lifetime. This seems wrong/unnecessary: We are creating a heap-type, a heap-type's name is stored as a unicode object anyway!
So, there is no reason to require the string be persistent, and a program that decides to build a custom name dynamically (for whatever reasons) would run into a crash when the name is accessed.
The code:
https://github.com/python/cpython/blob/0c50b8c0b8274d54d6b71ed7bd21057d3642f138/Objects/typeobject.c#L3427
Should be modified to point to to the `ht_name` (utf8) data instead. My guess is, the simplest solution is calling `type_set_name`, even if that runs some unnecessary checks.
I understand that the FromSpec API is mostly designed to replace the static type definition rather than extend it, but it seems an unintentional/strange requirement.

> the simplest solution is calling `type_set_name`, even if that runs some unnecessary checks.
Hm, I haven't find any case who use dynamical tp_name of Type_Spec temporarily.
If we meet this user case, Adding a new object pointer of type name in is an other option maybe:)

> Hm, I haven't find any case who use dynamical tp_name of Type_Spec temporarily.
The use case is creating types entirely on demand, with dynamically created specs.
This is useful e.g. for wrapping objects of a different object system, like C++ classes or Qt/GTK widgets.
But this issue is not about adding new API to enable a new use case. The *current* API can reasonably be used with a dynamic name string. So we shouldn't wait until someone tells us they need this fixed :)
So this should either be fixed or the requirement should be documented. (And the documentation would IMO sound like we're acknowledging a design bug, so it's better to fix.)

> the simplest solution is calling `type_set_name`, even if that runs some unnecessary checks.
Unfortunately this won't work, because it sets ht_name to the same value as tp_name. For historical reasons, the two can be different (and often are) for types created with PyType_From*Spec*.
I haven't found a way to fix this issue without adding yet another pointer to the PyHeapTypeObject struct.

New changeset 8a310dd5f4242b5d28013c1905c6573477e3b957 by Petr Viktorin in branch 'main':
bpo-45315: PyType_FromSpec: Copy spec->name and have the type own the memory for its name (GH-29103)
https://github.com/python/cpython/commit/8a310dd5f4242b5d28013c1905c6573477e3b957

Since the fix changes the size of PyObject, it can't be backported.