[3.14] GH-148726: Forward-port generational GC by sergey-miryanov · Pull Request #148720 · python/cpython

sergey-miryanov · 2026-04-18T10:55:10Z

📚 Documentation preview 📚: https://cpython-previews--148720.org.readthedocs.build/

Issue: Forward-port generational GC #148726

Co-Authored-By: Neil Schemenauer <nas@arctrix.com> Co-Authored-By: Sergey Miryanov <sergey.miryanov@gmail.com>

Co-Authored-By: Zanie Blue <contact@zanie.dev>

nascheme · 2026-04-24T16:34:46Z

I've done a second pass of review and this looks good to merge. One minor nit, the Include/internal/pycore_interp_structs.h still has the _GCPhase enum, which is now unused.

nascheme · 2026-04-24T21:56:43Z

@hugovk I believe as release manager, you need to review the ABI changes (should be compatible, IMHO). I think when that's done, we need to commit the updated ABI file into this branch, before we can merge.

bedevere-bot · 2026-04-25T14:50:32Z

🤖 New build scheduled with the buildbot fleet by @hugovk for commit 39e803e 🤖

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…e-142516.GcGen315.rst Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>

Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>

bedevere-bot · 2026-04-26T06:29:48Z

🤖 New build scheduled with the buildbot fleet by @hugovk for commit ba7443e 🤖

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hugovk · 2026-04-26T13:56:58Z

These buildbots failures look unrelated: pre-existing failures or flaky tests.

This MR contains the following updates: | Package | Update | Change | |---|---|---| | [uv](https://github.com/astral-sh/uv) | patch | `0.11.7` → `0.11.11` | MR created with the help of [el-capitano/tools/renovate-bot](https://gitlab.com/el-capitano/tools/renovate-bot). **Proposed changes to behavior should be submitted there as MRs.** --- ### Release Notes <details> <summary>astral-sh/uv (uv)</summary> ### [`v0.11.11`](https://github.com/astral-sh/uv/blob/HEAD/CHANGELOG.md#01111) [Compare Source](astral-sh/uv@0.11.10...0.11.11) Released on 2026-05-06. ##### Bug fixes - Accept legacy ID format from pre-0.11.9 cache entries ([#19301](astral-sh/uv#19301)) ### [`v0.11.10`](https://github.com/astral-sh/uv/blob/HEAD/CHANGELOG.md#01110) [Compare Source](astral-sh/uv@0.11.9...0.11.10) Released on 2026-05-05. ##### Bug fixes - Allow pre-release Python requests with non-zero patch versions ([#19286](astral-sh/uv#19286)) ### [`v0.11.9`](https://github.com/astral-sh/uv/blob/HEAD/CHANGELOG.md#0119) [Compare Source](astral-sh/uv@0.11.8...0.11.9) Released on 2026-05-04. This release includes a special release candidate for the next Python 3.14 patch release. Python 3.14 included a new garbage collection implementation, which reduced pause times but caused significant unexpected memory pressure in production environments. In 3.14.5 and 3.15, the previous garbage collection implementation will be restored. We would greatly appreciate if you tested the 3.14.5rc1 version included in this release. The stable version is expected to be released soon and any feedback on potential issues would be helpful to the Python development team. For more context, see the [announcement](https://discuss.python.org/t/reverting-the-incremental-gc-in-python-3-14-and-3-15/107014), [issue](python/cpython#148726), and [pull request](python/cpython#148720). Issues with the new release can be reported in the uv or CPython issue trackers. ##### Python - Upgrade PyPy to v7.3.22 - Add CPython 3.14.5rc1 - On macOS, CPython statically links `libpython` to match Linux ##### Enhancements - Omit compatible release desugaring for pre-release hints ([#19267](astral-sh/uv#19267)) - Fix file locks on Android ([#18323](astral-sh/uv#18323)) ##### Preview - `uv audit` add reporting for adverse project statuses ([#19128](astral-sh/uv#19128)) ##### Bug fixes - Discover versioned Python executables when `requires-python` pins a version ([#18700](astral-sh/uv#18700)) - Fix URL prefix matching to require path boundaries ([#19154](astral-sh/uv#19154)) - Fix transitive Git path dependencies in lockfiles ([#19269](astral-sh/uv#19269)) - Handle incorrect unlock error in `LockedFile::drop` on Wine ([#19229](astral-sh/uv#19229)) - Prevent uninstalling site-packages for empty `top_level.txt` in `.egg-info` ([#19114](astral-sh/uv#19114)) - Use symlinks instead of junctions on Wine ([#19213](astral-sh/uv#19213)) - Fix floating-point environment handling on ARMv7 ([#19157](astral-sh/uv#19157)) - Redact credentials from remote requirements URL in offline errors ([#19216](astral-sh/uv#19216)) - Windows tramplolines no longer set `PYTHONHOME` and only set `__PYVENV_LAUNCHER__` for virtual environments ([#19199](astral-sh/uv#19199)) ##### Documentation - Mark `--native-tls` and `UV_NATIVE_TLS` as deprecated ([#18705](astral-sh/uv#18705)) - Re-add `pytorch-triton-rocm` to PyTorch ROCm docs ([#19241](astral-sh/uv#19241)) - Tweak changelog entries for 0.11.8 ([#19188](astral-sh/uv#19188)) - Add 'Exporting lockfiles' to the Concepts->Projects index ([#19209](astral-sh/uv#19209)) - Clarify that `uv init` creates git files / folders in the projects guide ([#19183](astral-sh/uv#19183)) ### [`v0.11.8`](https://github.com/astral-sh/uv/blob/HEAD/CHANGELOG.md#0118) [Compare Source](astral-sh/uv@0.11.7...0.11.8) Released on 2026-04-27. ##### Enhancements - Add `--python-downloads-json-url` to `python pin` ([#19092](astral-sh/uv#19092)) - Fetch uv from Astral mirror during self-update ([#18682](astral-sh/uv#18682)) - Support `pip uninstall -y` ([#19082](astral-sh/uv#19082)) - Allow `exclude-newer` to be missing from the lockfile when `exclude-newer-span` is present ([#19024](astral-sh/uv#19024)) - Only show the version number in `uv self version --short` ([#19019](astral-sh/uv#19019)) - Silence warnings on empty `SSL_CERT_DIR` directory ([#19018](astral-sh/uv#19018)) - Use a sentinel timestamp for relative `exclude-newer` and `exclude-newer-package` values in lockfiles ([#19022](astral-sh/uv#19022), [#19101](astral-sh/uv#19101)) ##### Configuration - Add `UV_PYTHON_NO_REGISTRY` ([#19035](astral-sh/uv#19035)) - Add an environment variable for `UV_NO_PROJECT` ([#19052](astral-sh/uv#19052)) - Expose `UV_PYTHON_SEARCH_PATH` for Python discovery `PATH` overrides ([#19034](astral-sh/uv#19034)) ##### Bug fixes - Add `rust-toolchain.toml` to uv-build sdist ([#19131](astral-sh/uv#19131)) - Ensure uv invocations of git do not inherit repository location environment variables ([#19088](astral-sh/uv#19088)) - Redact pre-signed upload URLs in verbose output ([#19146](astral-sh/uv#19146)) - Handle transitive URL dependencies in PEP 517 build requirements ([#19076](astral-sh/uv#19076), [#19086](astral-sh/uv#19086)) - Support `uv lock` on a `pyproject.toml` that only contains dependency-groups ([#19087](astral-sh/uv#19087)) - Disable transparent Python upgrades in projects when a patch version is requested via `.python-version` ([#19102](astral-sh/uv#19102)) - Fix Python variant tagging in the Windows registry ([#19012](astral-sh/uv#19012)) - Ban external symlinks in `.tar.zst` wheels ([#19144](astral-sh/uv#19144)) ##### Distributions - Remove deprecated license classifiers from uv-build and add Python 3.14 classifier ([#19130](astral-sh/uv#19130)) ##### Documentation - Bump astral-sh/setup-uv version in docs ([#19030](astral-sh/uv#19030)) - Update PyTorch documentation for PyTorch 2.11 ([#19095](astral-sh/uv#19095)) </details> --- ### Configuration 📅 **Schedule**: (UTC) - Branch creation - At any time (no schedule defined) - Automerge - At any time (no schedule defined) 🚦 **Automerge**: Disabled by config. 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sergey-miryanov added 3 commits April 18, 2026 15:54

Forward-port generational GC.

1d75f5d

Co-Authored-By: Neil Schemenauer <nas@arctrix.com> Co-Authored-By: Sergey Miryanov <sergey.miryanov@gmail.com>

Update gc.rst

00a7baa

Co-Authored-By: Zanie Blue <contact@zanie.dev>

Update InternalDocs/garbge_collector.md

14547a0

Co-Authored-By: Zanie Blue <contact@zanie.dev>

sergey-miryanov changed the title ~~Feat/gc gen 3.14~~ Forward-port generational GC Apr 18, 2026

Fix tests, typos, add news entry

e989c16

Co-Authored-By: Zanie Blue <contact@zanie.dev>

sergey-miryanov changed the title ~~Forward-port generational GC~~ [3.14] GH-148726: Forward-port generational GC Apr 18, 2026

bedevere-app Bot mentioned this pull request Apr 18, 2026

Forward-port generational GC #148726

Closed

sergey-miryanov mentioned this pull request Apr 18, 2026

gh-142516: Forward-port generational GC #148687

Closed

sergey-miryanov and others added 7 commits April 18, 2026 22:43

Recheck and remove self notes

bfc44ab

Remove vestigial comment about "old space bit'.

dbd944e

Remove reference to "incremental GC".

9c22083

Revert to 3.13 limits for these tests.

b50da36

Add notes about untrack_dicts() change.

8153914

Merge branch '3.14' into feat/gc-gen-3.14

e8035ec

Use PyErr_FormatUnraisable

3cba502

sergey-miryanov marked this pull request as ready for review April 23, 2026 19:30

sergey-miryanov requested review from ericsnowcurrently and pablogsal as code owners April 23, 2026 19:30

bedevere-app Bot added the awaiting review label Apr 23, 2026

zanieb mentioned this pull request Apr 23, 2026

[3.14] Forward-port generational GC (GH-142516) #148694

Closed

sergey-miryanov and others added 3 commits April 24, 2026 22:33

Remove _GCPhase

a9a948f

Merge branch '3.14' into feat/gc-gen-3.14

ed6ab86

Merge branch '3.14' into feat/gc-gen-3.14

a6fd7cc

nascheme enabled auto-merge (squash) April 24, 2026 21:08

hugovk reviewed Apr 25, 2026

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Comment thread Doc/library/gc.rst

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hugovk disabled auto-merge April 25, 2026 12:16

Update ABI dump

39e803e

hugovk requested a review from encukou as a code owner April 25, 2026 14:27

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sergey-miryanov and others added 3 commits April 26, 2026 01:01

Update Misc/NEWS.d/next/Core_and_Builtins/2026-04-17-11-30-00.gh-issu…

3e1f41b

…e-142516.GcGen315.rst Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>

Update gc.rst

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More fixes for gc.rst

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Update Doc/library/gc.rst

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Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>

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hugovk merged commit 9a7e205 into python:3.14 Apr 26, 2026
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sergey-miryanov mentioned this pull request Apr 28, 2026

[3.14] GH-148726: Add heap_size to _gc_runtime_state #149025

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vstinner mentioned this pull request Apr 30, 2026

Observed memory leak in ssl library: Python 3.14 GC issue #142516

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BrewTestBot mentioned this pull request May 5, 2026

uv 0.11.9 Homebrew/homebrew-core#280944

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[3.14] GH-148726: Forward-port generational GC#148720

[3.14] GH-148726: Forward-port generational GC#148720
hugovk merged 19 commits intopython:3.14from
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