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v0.5.1
https://github.com/python/cpython
09 December 2020, 11:06:31 UTC
Revision 972aba86ede0bf254e16a760639a1ff8df298578 authored by Antoine Pitrou on 10 June 2020, 20:38:42 UTC, committed by GitHub on 10 June 2020, 20:38:42 UTC 
[3.8] bpo-40895: Update weakref documentation to remove old warnings (GH-20687) (GH-20792)
 


The doccumentation at https://docs.python.org/3.10/library/weakref.html cautions that the `WeakKeyDictionary` and `WeakValueDictionary` are susceptible to the problem of dictionary mutation during iteration.

These notes present the user with a problem that has no easy solution.

I dug into the implementation and found that fortunately, Antoine Pitrou already addressed this challenge (10 years ago!) by introducing an `_IterationGuard` context manager to the implementation, which delays mutation while an iteration is in progress.

I asked for confirmation and @pitrou agreed that these notes could be removed:
https://github.com/python/cpython/commit/c1baa601e2b558deb690edfdf334fceee3b03327GH-commitcomment-39514438.
(cherry picked from commit 1642c0ef750f96664a98cadb09301d492098d2fb)

Co-authored-by: Daniel Fortunov <asqui@users.noreply.github.com>

Automerge-Triggered-By: @pitrou
1 parent c7a6c7b
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Tip revision: 972aba86ede0bf254e16a760639a1ff8df298578 authored by Antoine Pitrou on 10 June 2020, 20:38:42 UTC
[3.8] bpo-40895: Update weakref documentation to remove old warnings (GH-20687) (GH-20792)
Tip revision: 972aba8
warnings.h 
#ifndef Py_WARNINGS_H
#define Py_WARNINGS_H
#ifdef __cplusplus
extern "C" {
#endif

#ifndef Py_LIMITED_API
PyAPI_FUNC(PyObject*) _PyWarnings_Init(void);
#endif

PyAPI_FUNC(int) PyErr_WarnEx(
    PyObject *category,
    const char *message,        /* UTF-8 encoded string */
    Py_ssize_t stack_level);
PyAPI_FUNC(int) PyErr_WarnFormat(
    PyObject *category,
    Py_ssize_t stack_level,
    const char *format,         /* ASCII-encoded string  */
    ...);

#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03060000
/* Emit a ResourceWarning warning */
PyAPI_FUNC(int) PyErr_ResourceWarning(
    PyObject *source,
    Py_ssize_t stack_level,
    const char *format,         /* ASCII-encoded string  */
    ...);
#endif
#ifndef Py_LIMITED_API
PyAPI_FUNC(int) PyErr_WarnExplicitObject(
    PyObject *category,
    PyObject *message,
    PyObject *filename,
    int lineno,
    PyObject *module,
    PyObject *registry);
#endif
PyAPI_FUNC(int) PyErr_WarnExplicit(
    PyObject *category,
    const char *message,        /* UTF-8 encoded string */
    const char *filename,       /* decoded from the filesystem encoding */
    int lineno,
    const char *module,         /* UTF-8 encoded string */
    PyObject *registry);

#ifndef Py_LIMITED_API
PyAPI_FUNC(int)
PyErr_WarnExplicitFormat(PyObject *category,
                         const char *filename, int lineno,
                         const char *module, PyObject *registry,
                         const char *format, ...);
#endif

/* DEPRECATED: Use PyErr_WarnEx() instead. */
#ifndef Py_LIMITED_API
#define PyErr_Warn(category, msg) PyErr_WarnEx(category, msg, 1)
#endif

#ifndef Py_LIMITED_API
void _PyErr_WarnUnawaitedCoroutine(PyObject *coro);
#endif

#ifdef __cplusplus
}
#endif
#endif /* !Py_WARNINGS_H */
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