https://github.com/python/cpython/commit/67862fc75e6cf991af757b5184602bbaeac97cae commit: 67862fc75e6cf991af757b5184602bbaeac97cae branch: 3.14 author: Miss Islington (bot) <[email protected]> committer: kumaraditya303 <[email protected]> date: 2026-03-27T13:07:37Z summary:
[3.14] gh-142518: add thread safety docs on bytes C-API (GH-146415) (#146515) gh-142518: add thread safety docs on bytes C-API (GH-146415) (cherry picked from commit 6a94980301b880b7ac1178efd31d14f031f690f5) Co-authored-by: Kumar Aditya <[email protected]> files: M Doc/c-api/bytes.rst M Doc/data/threadsafety.dat diff --git a/Doc/c-api/bytes.rst b/Doc/c-api/bytes.rst index 7d8a511e100cf4..3a34b5329eb7ef 100644 --- a/Doc/c-api/bytes.rst +++ b/Doc/c-api/bytes.rst @@ -123,6 +123,10 @@ called with a non-bytes parameter. Return the bytes representation of object *o* that implements the buffer protocol. + .. note:: + If the object implements the buffer protocol, then the buffer + must not be mutated while the bytes object is being created. + .. c:function:: Py_ssize_t PyBytes_Size(PyObject *o) @@ -181,6 +185,9 @@ called with a non-bytes parameter. created, the old reference to *bytes* will still be discarded and the value of *\*bytes* will be set to ``NULL``; the appropriate exception will be set. + .. note:: + If *newpart* implements the buffer protocol, then the buffer + must not be mutated while the new bytes object is being created. .. c:function:: void PyBytes_ConcatAndDel(PyObject **bytes, PyObject *newpart) @@ -188,6 +195,10 @@ called with a non-bytes parameter. appended to *bytes*. This version releases the :term:`strong reference` to *newpart* (i.e. decrements its reference count). + .. note:: + If *newpart* implements the buffer protocol, then the buffer + must not be mutated while the new bytes object is being created. + .. c:function:: PyObject* PyBytes_Join(PyObject *sep, PyObject *iterable) @@ -206,6 +217,9 @@ called with a non-bytes parameter. .. versionadded:: 3.14 + .. note:: + If *iterable* objects implement the buffer protocol, then the buffers + must not be mutated while the new bytes object is being created. .. c:function:: int _PyBytes_Resize(PyObject **bytes, Py_ssize_t newsize) diff --git a/Doc/data/threadsafety.dat b/Doc/data/threadsafety.dat index 103e8ef3e97ed1..1210ab17aaa35b 100644 --- a/Doc/data/threadsafety.dat +++ b/Doc/data/threadsafety.dat @@ -66,10 +66,44 @@ PyList_Reverse:shared: # is a list PyList_SetSlice:shared: -# Sort - per-object lock held; comparison callbacks may execute -# arbitrary Python code +# Sort - per-object lock held; the list is emptied before sorting +# so other threads may observe an empty list, but they won't see the +# intermediate states of the sort PyList_Sort:shared: # Extend - lock target list; also lock source when it is a # list, set, or dict PyList_Extend:shared: + +# Creation - pure allocation, no shared state +PyBytes_FromString:atomic: +PyBytes_FromStringAndSize:atomic: +PyBytes_DecodeEscape:atomic: + +# Creation from formatting C primitives - pure allocation, no shared state +PyBytes_FromFormat:atomic: +PyBytes_FromFormatV:atomic: + +# Creation from object - uses buffer protocol so may call arbitrary code; +# safe as long as the buffer is not mutated by another thread during the operation +PyBytes_FromObject:shared: + +# Size - uses atomic load on free-threaded builds +PyBytes_Size:atomic: +PyBytes_GET_SIZE:atomic: + +# Raw data - no locking; mutating it is unsafe if the bytes object is shared between threads +PyBytes_AsString:compatible: +PyBytes_AS_STRING:compatible: +PyBytes_AsStringAndSize:compatible: + +# Concatenation - uses buffer protocol; safe as long as buffer is not mutated by another thread during the operation +PyBytes_Concat:shared: +PyBytes_ConcatAndDel:shared: +PyBytes_Join:shared: + +# Resizing - safe if the object is unique +_PyBytes_Resize:distinct: + +# Repr - atomic as bytes are immutable +PyBytes_Repr:atomic: _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
