* Count number of actually tracked objects, instead of trackable objects. This ensures that untracking tuples has the desired effect of reducing GC overhead
* Do not track most untrackable tuples during creation. This prevents large numbers of small tuples causing execessive GCs.
Fix memory leak in sub-interpreter creation caused by overwriting of the previously used `_malloced` field. Now the pointer is stored in the first word of the memory block to avoid it being overwritten accidentally.
Co-authored-by: Kumar Aditya <kumaraditya@python.org>
Previously, the _BlocksOutputBuffer code creates a list of bytes objects to handle the output data from compression libraries. This ends up being slow due to the output buffer code needing to copy each bytes element of the list into the final bytes object buffer at the end of compression.
The new PyBytesWriter API introduced in PEP 782 is an ergonomic and fast method of writing data into a buffer that will later turn into a bytes object. Benchmarks show that using the PyBytesWriter API is 10-30% faster for decompression across a variety of settings. The performance gains are greatest when the decompressor is very performant, such as for Zstandard (and likely zlib-ng). Otherwise the decompressor can bottleneck decompression and the gains are more modest, but still sizable (e.g. 10% faster for zlib)!
Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
Revert GH-131993.
Fix swallowing some syntax warnings in different modules if they accidentally
have the same message and are emitted from the same line.
Fix memory leak in sub-interpreter creation caused by overwriting of the previously used `_malloced` field. Now the pointer is stored in the first word of the memory block to avoid it being overwritten accidentally.
Co-authored-by: Kumar Aditya <kumaraditya@python.org>
* Move PyUnicode_Format() implementation from unicodeobject.c
to unicode_format.c.
* Replace unicode_modifiable() with _PyUnicode_IsModifiable()
* Add empty lines to have two empty lines between functions.
* Move Python/formatter_unicode.c to Objects/unicode_formatter.c.
* Move Objects/stringlib/localeutil.h content into
unicode_formatter.c. Remove localeutil.h.
* Move _PyUnicode_InsertThousandsGrouping() to unicode_formatter.c
and mark the function as static.
* Rename unicode_fill() to _PyUnicode_Fill() and export it in
pycore_unicodeobject.h.
* Move MAX_UNICODE to pycore_unicodeobject.h as _Py_MAX_UNICODE.
Expose the XML Expat 2.7.2 APIs to tune protections against
"billion laughs" [1] attacks.
The exposed APIs are available on Expat parsers, that is,
parsers created by `xml.parsers.expat.ParserCreate()`, as:
- `parser.SetBillionLaughsAttackProtectionActivationThreshold(threshold)`, and
- `parser.SetBillionLaughsAttackProtectionMaximumAmplification(max_factor)`.
This completes the work in f04bea44c3,
and improves the existing related documentation.
[1]: https://en.wikipedia.org/wiki/Billion_laughs_attack
Expose the XML Expat 2.7.2 mitigation APIs to disallow use of
disproportional amounts of dynamic memory from within an Expat
parser (see CVE-2025-59375 for instance).
The exposed APIs are available on Expat parsers, that is,
parsers created by `xml.parsers.expat.ParserCreate()`, as:
- `parser.SetAllocTrackerActivationThreshold(threshold)`, and
- `parser.SetAllocTrackerMaximumAmplification(max_factor)`.
Replace PyBytes_FromStringAndSize() and _PyBytes_Resize() with the
PyBytesWriter API.
Add _PyBytesWriter_GetSize() and _PyBytesWriter_GetData() static
inline functions.
With https://github.com/llvm/llvm-project/pull/150201 being merged, there is
now a better way to generate the Emscripten trampoline, instead of including
hand-generated binary WASM content. Requires Emscripten 4.0.12.
There was a deadlock originally seen by Memray when a daemon thread
enabled or disabled profiling while the interpreter was shutting down.
I think this could also happen with garbage collection, but I haven't
seen that in practice.
The daemon thread could be hung while trying acquire the global rwmutex
that prevents overlapping global and per-interpreter stop-the-world events.
Since it already held the main interpreter's stop-the-world lock, it
also deadlocked the main thread, which is trying to perform interpreter
finalization.
Swap the order of lock acquisition to prevent this deadlock.
Additionally, refactor `_PyParkingLot_Park` so that the global buckets
hashtable is left in a clean state if the thread is hung in
`PyEval_AcquireThread`.
Mikhail Efimov