On 1/12/21 4:34 PM, Antoine Pitrou wrote:
On Tue, 12 Jan 2021 15:22:36 +0100
Petr Viktorin <encu...@gmail.com> wrote:
On 1/11/21 5:26 PM, Victor Stinner wrote:
Hi,
There are multiple PEPs covering heap types. The latest one refers to
other PEPs: PEP 630 "Isolating Extension Modules" by Petr Viktorin.
https://www.python.org/dev/peps/pep-0630/#motivation
The use case is to embed multiple Python instances (interpreters) in
the same application process, or to embed Python with multiple calls
to Py_Initialize/Py_Finalize (sequentially, not in parallel). Static
types are causing different issues for these use cases.
If a type is immutable and has no references to heap-allocated objects,
it could stay as a static type.
The issue is that very many types don't fit that. For example, if some
method needs to raise a module-specific exception, that's a reference to
a heap-allocated type, because custom exceptions generally aren't static.
Aren't we confusing two different things here?
- a mutable *type*, i.e. a type with mutable state attached to itself
(not to instances)
- a mutable *instance*, where the mutable state is per-instance
While it's very common for custom exceptions to have mutable instance
state (e.g. a backend-specific error number), I can't think of any
custom exception that has mutable state attached to the exception
*type*.
You're right, exception types *could* generally be static. However, the
most common API for creating them, PyErr_NewException[WithDoc], creates
heap types.
_______________________________________________
Python-Dev mailing list -- python-dev@python.org
To unsubscribe send an email to python-dev-le...@python.org
https://mail.python.org/mailman3/lists/python-dev.python.org/
Message archived at
https://mail.python.org/archives/list/python-dev@python.org/message/ZSQ4HGBIMFBOVXBUKB7C7UPIJPW76OLA/
Code of Conduct: http://python.org/psf/codeofconduct/
