Removal of _Py_ForgetReference from public header in 3.9 issue
Please excuse if this is the wrong mailing list. I couldn't find one for module maintainers. I maintain an open source Python module in C. I'm trying to verify for the first time that the module still works with cpython 3.9. This module does *not* use the "limited" C API. In building my module against 3.9b3, I'm getting a missing declaration warning on _Py_ForgetReference. My module builds and passes test fine, this is just a compiler warning issue. The change that caused this was made in: commit f58bd7c1693fe041f7296a5778d0a11287895648 Author: Victor Stinner <vstinner@python.org> Date: Wed Feb 5 13:12:19 2020 +0100 bpo-39542: Make PyObject_INIT() opaque in limited C API (GH-18363) ... I definitely need the _Py_ForgetReference call for a particularly hairy error condition (https://github.com/jnwatson/py-lmdb/blob/master/lmdb/cpython.c#L888 if you're curious). In fact, my tests will seg fault if I don't have that call and trace refs is enabled. Should I put an #ifdef Py_TRACE_REFS around the call? Ignore it? What do you think is the proper resolution? Nic Watson
On 2020-06-14 22:10, cpython@nicwatson.org wrote:
Please excuse if this is the wrong mailing list. I couldn't find one for module maintainers.
This is relevant to capi-sig@python.org; let's continue here.
I maintain an open source Python module in C. I'm trying to verify for the first time that the module still works with cpython 3.9. This module does *not* use the "limited" C API.
In building my module against 3.9b3, I'm getting a missing declaration warning on _Py_ForgetReference. My module builds and passes test fine, this is just a compiler warning issue.
What does the _Py_ForgetReference function do? The [documentation] says it's only for use in the interpereter core, so I'd assume it's . [documentation]: https://docs.python.org/3/c-api/refcounting.html
The change that caused this was made in:
commit f58bd7c1693fe041f7296a5778d0a11287895648 Author: Victor Stinner <vstinner@python.org> Date: Wed Feb 5 13:12:19 2020 +0100
bpo-39542: Make PyObject_INIT() opaque in limited C API (GH-18363) ...
I definitely need the _Py_ForgetReference call for a particularly hairy error condition (https://github.com/jnwatson/py-lmdb/blob/master/lmdb/cpython.c#L888 if you're curious). In fact, my tests will seg fault if I don't have that call and trace refs is enabled.
I can't follow the reasoning behind the code easily. Why do you use _Py_ForgetReference and PyObject_Del, instead of Py_DECREF(self)?
Should I put an #ifdef Py_TRACE_REFS around the call? Ignore it? What do you think is the proper resolution?
On 15.06.2020 11:02, Petr Viktorin wrote:
On 2020-06-14 22:10, cpython@nicwatson.org wrote:
I maintain an open source Python module in C. I'm trying to verify for the first time that the module still works with cpython 3.9. This module does *not* use the "limited" C API.
In building my module against 3.9b3, I'm getting a missing declaration warning on _Py_ForgetReference. My module builds and passes test fine, this is just a compiler warning issue.
What does the _Py_ForgetReference function do? The [documentation] says it's only for use in the interpereter core, so I'd assume it's .
[documentation]: https://docs.python.org/3/c-api/refcounting.html
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participants (3)
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cpython＠nicwatson.org -
M.-A. Lemburg -
Petr Viktorin