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Perf trampoline fails to build on macOS < 10.12 #140421
Description
Bug report
Bug description:
The code uses clock_gettime which was added in macOS 10.12, and also MAP_ANONYMOUS which is sometimes spelled MAP_ANON. I was initially going to suggest just disabling this feature on the older systems, but actually fixing it for all x86 Macs turned out to be fairly simple, so I'll be opening a PR that does that shortly.
CPython versions tested on:
3.15
Operating systems tested on:
macOS
Activity
pythongh-140421: Fix perf trampoline on older macOS
hugovk commentedon Oct 21, 2025
macOS 10.11 El Capitan is pretty old, it was EOL in 2018.
macOS 10.12 Sierra was released in 2016, and the Python macOS installer supports 10.15 Catalina and later:
https://docs.python.org/3/using/mac.html#using-python-for-macos-from-python-org
But I'll let the JIT maintainers decide about this change.
gpshead commentedon Nov 11, 2025
Closing this as 10.12 has been unsupported by Apple for 6 years.
jmroot commentedon Nov 11, 2025
@gpshead Would you accept a patch to simply disable the feature where it won't build?
barracuda156 commentedon Jan 21, 2026
@gpshead @hugovk This should be reconsidered. There are a lot of users of < 10.12, and pretty much all of them are using Python in some way (at least for dependents). @jmroot maintains Python ports in MacPorts for years, and unless you see an error in his fix, it is a good idea to accept it.
hugovk commentedon Jan 21, 2026
The oldest version of Python accepting bugfixes, and with a macOS installer, is 3.13. The 3.13 installer requires macOS 10.13 or later and
3.14 requires 10.15 or later.
That means if you're using Python for older macOS, you're already need to build from source, so can also patch as needed.
I don't have numbers for how many < 10.12 users there are.
To try and get an idea, here's a week's worth of PyPI downloads for urllib3, which is has a billion downloads per month and is the most-downloaded, non-AWS-specific package, so hard to avoid.
Out of 283,920,840 total downloads, 3,153,585 or 1.1% are for macOS:
4520 downloads out of 3.1mscript-and-data.zip
barracuda156 commentedon Jan 21, 2026
Of course; nobody asks for pre-compiled binaries for legacy macOS. But the same case is with a lot of platforms, including modern ones; I don’t think Python upstream provides pre-built pythons for every feasible combo of latest release of every OS and every arch supported by it.
Yes, but a) that leaves it broken for anyone who tries to build without MacPorts; b) multiple downstreams should either repeat the same work to fix it or find an existing fix across other downstreams; c) requires every downstream to keep rebasing a patch for likely completely unrelated changes in the source (i.e. there is zero maintenance effort for the upstream, but a lot of ongoing maintenance for every downstream).
barracuda156 commentedon Jan 21, 2026
P. S. This also de-incentivizes potential contributors to submit any fixes later on, which won’t be limited to a platform that is not supported by upstream. This is an unseen consequence, but it is there.
pythongh-140421: Disable perf trampoline on older macOS
gh-140421: Disable perf trampoline on older macOS (#144647)
ned-deily commentedon Feb 11, 2026
Thanks for the PR. I think this is a minor but very low-risk change that makes life a bit easier for projects (like MacPorts) that support older macOS versions and older Mac hardware.
pythongh-140421: Disable perf trampoline on older macOS (python#144647)
pythongh-140421: Disable perf trampoline on older macOS (python#144647)
pythongh-140421: Disable perf trampoline on older macOS (python#144647)