René's URL Explorer Experiment


Title: gh-149816: #96 Fix a race condition in invoke_gc_callback with free threading by dzaramelcone · Pull Request #150029 · python/cpython · GitHub

Open Graph Title: gh-149816: #96 Fix a race condition in invoke_gc_callback with free threading by dzaramelcone · Pull Request #150029 · python/cpython

X Title: gh-149816: #96 Fix a race condition in invoke_gc_callback with free threading by dzaramelcone · Pull Request #150029 · python/cpython

Description: The optimization that avoided allocating an info dict when no gc callbacks were registered introduces a time of check to time of use race in free threaded mode (lineno 1943-1955). I just pulled out the check. Since info is always non-null, I also replaced XDECREF use with DECREF. (lineno 1959, lineno 1982). I implemented a stress test for this and uncovered what I believe to be a bug with _PyList_GetItemRef. I am following suit with python/cpython#149909 and not including the test with my PR for two reasons: My implementation was resource intensive and not deterministic. I didn't want to scope creep fixing the bug with _PyList_GetItemRef (but I'm happy to open an issue for it!) also, this is my first PR against CPython, I am doing it from PyCon US as part of the sprint! :) Hello world! Issue: gh-149816

Open Graph Description: The optimization that avoided allocating an info dict when no gc callbacks were registered introduces a time of check to time of use race in free threaded mode (lineno 1943-1955). I just pulled out...

X Description: The optimization that avoided allocating an info dict when no gc callbacks were registered introduces a time of check to time of use race in free threaded mode (lineno 1943-1955). I just pulled out...

Opengraph URL: https://github.com/python/cpython/pull/150029

X: @github

direct link

Domain: github.com

route-pattern/:user_id/:repository/pull/:id/files(.:format)
route-controllerpull_requests
route-actionfiles
fetch-noncev2:1ccebc78-58e1-ad33-e031-f91682607ed0
current-catalog-service-hashae870bc5e265a340912cde392f23dad3671a0a881730ffdadd82f2f57d81641b
request-idC000:17E40D:43B951:5BEC75:6A524A79
html-safe-nonce4f269f0b07f7a77305f58b7b27a1debaa1e53b187614e1e8b7ff0b02ea8efb5b
visitor-payloadeyJyZWZlcnJlciI6IiIsInJlcXVlc3RfaWQiOiJDMDAwOjE3RTQwRDo0M0I5NTE6NUJFQzc1OjZBNTI0QTc5IiwidmlzaXRvcl9pZCI6IjQ3NzAzNjAxMzgxMDMxNDcxMjkiLCJyZWdpb25fZWRnZSI6ImlhZCIsInJlZ2lvbl9yZW5kZXIiOiJpYWQifQ==
visitor-hmace1d4d1648d7946eb5327b6b1b1b01516f45fbeb823dadf60065076cc9f198e9e
hovercard-subject-tagpull_request:3704922916
github-keyboard-shortcutsrepository,pull-request-list,pull-request-conversation,pull-request-files-changed,copilot
google-site-verificationApib7-x98H0j5cPqHWwSMm6dNU4GmODRoqxLiDzdx9I
octolytics-urlhttps://collector.github.com/github/collect
analytics-location///pull_requests/show/files
fb:app_id1401488693436528
apple-itunes-appapp-id=1477376905, app-argument=https://github.com/python/cpython/pull/150029/files
twitter:imagehttps://avatars.githubusercontent.com/u/134235821?s=400&v=4
twitter:cardsummary_large_image
og:imagehttps://avatars.githubusercontent.com/u/134235821?s=400&v=4
og:image:altThe optimization that avoided allocating an info dict when no gc callbacks were registered introduces a time of check to time of use race in free threaded mode (lineno 1943-1955). I just pulled out...
og:site_nameGitHub
og:typeobject
hostnamegithub.com
expected-hostnamegithub.com
Noneb9a586c06a05a7a86fc7e3f4dbd03e42f6869085879aa184aa6369456dbd50fb
turbo-cache-controlno-preview
diff-viewunified
go-importgithub.com/python/cpython git https://github.com/python/cpython.git
octolytics-dimension-user_id1525981
octolytics-dimension-user_loginpython
octolytics-dimension-repository_id81598961
octolytics-dimension-repository_nwopython/cpython
octolytics-dimension-repository_publictrue
octolytics-dimension-repository_is_forkfalse
octolytics-dimension-repository_network_root_id81598961
octolytics-dimension-repository_network_root_nwopython/cpython
turbo-body-classeslogged-out env-production page-responsive full-width
disable-turbotrue
browser-stats-urlhttps://api.github.com/_private/browser/stats
browser-errors-urlhttps://api.github.com/_private/browser/errors
release7aed05249554b889eb33d002851a973eebcc7e91
ui-targetfull
theme-color#1e2327
color-schemelight dark

Links:

Skip to contenthttps://github.com/python/cpython/pull/150029/files#start-of-content
https://github.com/
Sign in https://github.com/login?return_to=https%3A%2F%2Fgithub.com%2Fpython%2Fcpython%2Fpull%2F150029%2Ffiles
GitHub CopilotWrite better code with AIhttps://github.com/features/copilot
GitHub Copilot appDirect agents from issue to mergehttps://github.com/features/ai/github-app
MCP RegistryNewIntegrate external toolshttps://github.com/mcp
ActionsAutomate any workflowhttps://github.com/features/actions
CodespacesInstant dev environmentshttps://github.com/features/codespaces
IssuesPlan and track workhttps://github.com/features/issues
Code ReviewManage code changeshttps://github.com/features/code-review
GitHub Advanced SecurityFind and fix vulnerabilitieshttps://github.com/security/advanced-security
Code securitySecure your code as you buildhttps://github.com/security/advanced-security/code-security
Secret protectionStop leaks before they starthttps://github.com/security/advanced-security/secret-protection
Why GitHubhttps://github.com/why-github
Documentationhttps://docs.github.com
Bloghttps://github.blog
Changeloghttps://github.blog/changelog
Marketplacehttps://github.com/marketplace
View all featureshttps://github.com/features
Enterpriseshttps://github.com/enterprise
Small and medium teamshttps://github.com/team
Startupshttps://github.com/enterprise/startups
Nonprofitshttps://github.com/solutions/industry/nonprofits
App Modernizationhttps://github.com/solutions/use-case/app-modernization
DevSecOpshttps://github.com/solutions/use-case/devsecops
DevOpshttps://github.com/solutions/use-case/devops
CI/CDhttps://github.com/solutions/use-case/ci-cd
View all use caseshttps://github.com/solutions/use-case
Healthcarehttps://github.com/solutions/industry/healthcare
Financial serviceshttps://github.com/solutions/industry/financial-services
Manufacturinghttps://github.com/solutions/industry/manufacturing
Governmenthttps://github.com/solutions/industry/government
View all industrieshttps://github.com/solutions/industry
View all solutionshttps://github.com/solutions
AIhttps://github.com/resources/articles?topic=ai
Software Developmenthttps://github.com/resources/articles?topic=software-development
DevOpshttps://github.com/resources/articles?topic=devops
Securityhttps://github.com/resources/articles?topic=security
View all topicshttps://github.com/resources/articles
Customer storieshttps://github.com/customer-stories
Events & webinarshttps://github.com/resources/events
Ebooks & reportshttps://github.com/resources/whitepapers
Business insightshttps://github.com/solutions/executive-insights
GitHub Skillshttps://skills.github.com
Documentationhttps://docs.github.com
Customer supporthttps://support.github.com
Community forumhttps://github.com/orgs/community/discussions
Trust centerhttps://github.com/trust-center
Partnershttps://github.com/partners
View all resourceshttps://github.com/resources
GitHub SponsorsFund open source developershttps://github.com/open-source/sponsors
Security Labhttps://securitylab.github.com
Maintainer Communityhttps://maintainers.github.com
Acceleratorhttps://github.com/open-source/accelerator
GitHub Starshttps://stars.github.com
Archive Programhttps://archiveprogram.github.com
Topicshttps://github.com/topics
Trendinghttps://github.com/trending
Collectionshttps://github.com/collections
Enterprise platformAI-powered developer platformhttps://github.com/enterprise
GitHub Advanced SecurityEnterprise-grade security featureshttps://github.com/security/advanced-security
Copilot for BusinessEnterprise-grade AI featureshttps://github.com/features/copilot/copilot-business
Premium SupportEnterprise-grade 24/7 supporthttps://github.com/enterprise/premium-support
Pricinghttps://github.com/pricing
Search syntax tipshttps://docs.github.com/search-github/github-code-search/understanding-github-code-search-syntax
documentationhttps://docs.github.com/search-github/github-code-search/understanding-github-code-search-syntax
Sign in https://github.com/login?return_to=https%3A%2F%2Fgithub.com%2Fpython%2Fcpython%2Fpull%2F150029%2Ffiles
Sign up https://github.com/signup?ref_cta=Sign+up&ref_loc=header+logged+out&ref_page=%2F%3Cuser-name%3E%2F%3Crepo-name%3E%2Fpull_requests%2Fshow%2Ffiles&source=header-repo&source_repo=python%2Fcpython
Reloadhttps://github.com/python/cpython/pull/150029/files
Reloadhttps://github.com/python/cpython/pull/150029/files
Reloadhttps://github.com/python/cpython/pull/150029/files
Please reload this pagehttps://github.com/python/cpython/pull/150029/files
python https://github.com/python
cpythonhttps://github.com/python/cpython
Please reload this pagehttps://github.com/python/cpython/pull/150029/files
Notifications https://github.com/login?return_to=%2Fpython%2Fcpython
Fork 35k https://github.com/login?return_to=%2Fpython%2Fcpython
Star 73.7k https://github.com/login?return_to=%2Fpython%2Fcpython
Code https://github.com/python/cpython
Issues 5k+ https://github.com/python/cpython/issues
Pull requests 2.3k https://github.com/python/cpython/pulls
Actions https://github.com/python/cpython/actions
Projects https://github.com/python/cpython/projects
Security and quality 0 https://github.com/python/cpython/security
Insights https://github.com/python/cpython/pulse
Code https://github.com/python/cpython
Issues https://github.com/python/cpython/issues
Pull requests https://github.com/python/cpython/pulls
Actions https://github.com/python/cpython/actions
Projects https://github.com/python/cpython/projects
Security and quality https://github.com/python/cpython/security
Insights https://github.com/python/cpython/pulse
Sign up for GitHub https://github.com/signup?return_to=%2Fpython%2Fcpython%2Fissues%2Fnew%2Fchoose
terms of servicehttps://docs.github.com/terms
privacy statementhttps://docs.github.com/privacy
Sign inhttps://github.com/login?return_to=%2Fpython%2Fcpython%2Fissues%2Fnew%2Fchoose
dzaramelconehttps://github.com/dzaramelcone
python:mainhttps://github.com/python/cpython/tree/main
dzaramelcone:gh-149816-96https://github.com/dzaramelcone/cpython/tree/gh-149816-96
Conversation 6 https://github.com/python/cpython/pull/150029
Commits 6 https://github.com/python/cpython/pull/150029/commits
Checks 50 https://github.com/python/cpython/pull/150029/checks
Files changed 3 https://github.com/python/cpython/pull/150029/files
gh-149816: #96 Fix a race condition in invoke_gc_callback with free threading https://github.com/python/cpython/pull/150029/files#top
Show all changes 6 commits https://github.com/python/cpython/pull/150029/files
2306df8 gh-149816: #96 Fix race condition in `invoke_gc_callback` with free t… dzaramelcone May 18, 2026 https://github.com/python/cpython/pull/150029/commits/2306df81e266a39094232b466ab78de2ee30caa7
c2b7dbe add gc callback mutation race regression test dzaramelcone May 29, 2026 https://github.com/python/cpython/pull/150029/commits/c2b7dbe6f66e07672833692c1ed8caaf401f5b3c
5c71bc1 Merge branch 'main' into gh-149816-96 dzaramelcone May 29, 2026 https://github.com/python/cpython/pull/150029/commits/5c71bc1bbe33d0f4a0e4eeb411bca34ce54b0ef6
a33bd91 Merge branch 'main' into gh-149816-96 dzaramelcone Jul 11, 2026 https://github.com/python/cpython/pull/150029/commits/a33bd91898450e73043d2277c9fa524783388681
062d75a gh-149816: Avoid allocating callback info for empty list dzaramelcone Jul 11, 2026 https://github.com/python/cpython/pull/150029/commits/062d75add98471658633d6ba74bbe84eda7947eb
f67ea2b Merge branch 'main' into gh-149816-96 dzaramelcone Jul 11, 2026 https://github.com/python/cpython/pull/150029/commits/f67ea2b066209adce775a6d6e3cdade84ca5f8ca
Clear filters https://github.com/python/cpython/pull/150029/files
Please reload this pagehttps://github.com/python/cpython/pull/150029/files
Please reload this pagehttps://github.com/python/cpython/pull/150029/files
test_gc.py https://github.com/python/cpython/pull/150029/files#diff-bd2c376990c346fa7609c27d99a8046ab27a0bd4465af51c0b645a803b771fe6
2026-05-18-12-32-33.gh-issue-149816.v18Ypf.rst https://github.com/python/cpython/pull/150029/files#diff-17792189f64c37fb5341c4038b252046a01665a61cd31d3033b4a46dbbb13c26
gc_free_threading.c https://github.com/python/cpython/pull/150029/files#diff-4722ae850a2da3e12f50815c0e3932627ebe67edeaa8b7f28a94f20c8698204d
Lib/test/test_free_threading/test_gc.pyhttps://github.com/python/cpython/pull/150029/files#diff-bd2c376990c346fa7609c27d99a8046ab27a0bd4465af51c0b645a803b771fe6
View file https://github.com/python/cpython/blob/f67ea2b066209adce775a6d6e3cdade84ca5f8ca/Lib/test/test_free_threading/test_gc.py
Open in desktop https://desktop.github.com
https://github.co/hiddenchars
https://github.com/python/cpython/pull/150029/{{ revealButtonHref }}
https://github.com/python/cpython/pull/150029/files#diff-bd2c376990c346fa7609c27d99a8046ab27a0bd4465af51c0b645a803b771fe6
https://github.com/python/cpython/pull/150029/files#diff-bd2c376990c346fa7609c27d99a8046ab27a0bd4465af51c0b645a803b771fe6
https://github.com/python/cpython/pull/150029/files#diff-bd2c376990c346fa7609c27d99a8046ab27a0bd4465af51c0b645a803b771fe6
https://github.com/python/cpython/pull/150029/files#diff-bd2c376990c346fa7609c27d99a8046ab27a0bd4465af51c0b645a803b771fe6
Misc/NEWS.d/next/Core_and_Builtins/2026-05-18-12-32-33.gh-issue-149816.v18Ypf.rsthttps://github.com/python/cpython/pull/150029/files#diff-17792189f64c37fb5341c4038b252046a01665a61cd31d3033b4a46dbbb13c26
View file https://github.com/python/cpython/blob/f67ea2b066209adce775a6d6e3cdade84ca5f8ca/Misc/NEWS.d/next/Core_and_Builtins/2026-05-18-12-32-33.gh-issue-149816.v18Ypf.rst
Open in desktop https://desktop.github.com
https://github.co/hiddenchars
https://github.com/python/cpython/pull/150029/{{ revealButtonHref }}
Python/gc_free_threading.chttps://github.com/python/cpython/pull/150029/files#diff-4722ae850a2da3e12f50815c0e3932627ebe67edeaa8b7f28a94f20c8698204d
View file https://github.com/python/cpython/blob/f67ea2b066209adce775a6d6e3cdade84ca5f8ca/Python/gc_free_threading.c
Open in desktop https://desktop.github.com
https://github.co/hiddenchars
https://github.com/python/cpython/pull/150029/{{ revealButtonHref }}
https://github.com/python/cpython/pull/150029/files#diff-4722ae850a2da3e12f50815c0e3932627ebe67edeaa8b7f28a94f20c8698204d
https://github.com/python/cpython/pull/150029/files#diff-4722ae850a2da3e12f50815c0e3932627ebe67edeaa8b7f28a94f20c8698204d
https://github.com/python/cpython/pull/150029/files#diff-4722ae850a2da3e12f50815c0e3932627ebe67edeaa8b7f28a94f20c8698204d
https://github.com/python/cpython/pull/150029/files#diff-4722ae850a2da3e12f50815c0e3932627ebe67edeaa8b7f28a94f20c8698204d
https://github.com/python/cpython/pull/150029/files#diff-4722ae850a2da3e12f50815c0e3932627ebe67edeaa8b7f28a94f20c8698204d
Please reload this pagehttps://github.com/python/cpython/pull/150029/files
https://github.com
Termshttps://docs.github.com/site-policy/github-terms/github-terms-of-service
Privacyhttps://docs.github.com/site-policy/privacy-policies/github-privacy-statement
Securityhttps://github.com/security
Statushttps://www.githubstatus.com/
Communityhttps://github.community/
Docshttps://docs.github.com/
Contacthttps://support.github.com?tags=dotcom-footer

Viewport: width=device-width

URLs of crawlers that visited me.