Python 3.15 by swap357 · Pull Request #10732 · numba/numba

swap357 · 2026-07-27T18:27:53Z

This PR adds Python 3.15 support to Numba.

Co-Authored-By: Claude Sonnet 4.6

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

… and op_GET_ITER stack behavior

…TANT. Python 3.15 emits this opcode for literals like -1 as well as builtins, so generalize the byteflow tracer and interpreter beyond AssertionError.

Locate LOAD_CONST dynamically instead of assuming a fixed offset after RESUME, which overwrote CACHE and triggered a fatal interpreter error.

…nstead of __cached__)

…itional comprehensions

esc · 2026-08-05T09:17:14Z

I ran [b65616d](https://github.com/numba/numba/pull/10732/commits/b65616d22572794422f068e5fd2d1484adec98ff) through numba-hatchery at numba/numba-hatchery#15 and the test suite passed without errors, this is a good sign.

esc

One version guard needs to be be brought into line.

And also the file:

docs/source/reference/support_tiers.rst

References the 3.14 free threaded build. I presume we want to indicate somehow that this also includes the 3/15 free threaded build, as I assume we wish to produce an artifact for those too?

See screenshot below:

Review-assisted by: Kimi K3 via kilo-cli

esc · 2026-08-05T15:39:42Z


    def op_GET_ITER(self, state, inst):
-        value = state.pop()
+        if PYVERSION >= (3, 15):


Suggested change

if PYVERSION >= (3, 15):

if PYVERSION in ((3, 15), ):

For consistency. The other version guards use this style.

Please also change the else if and else parts, such that a NotImplementedError is raised.

I've fixed two places which had open branches and made them explicit - fa3221e and 6bd6783

…eflow

swap357 · 2026-08-05T23:04:07Z

One version guard needs to be be brought into line.

And also the file:
docs/source/reference/support_tiers.rst
References the 3.14 free threaded build. I presume we want to indicate somehow that this also includes the 3/15 free threaded build, as I assume we wish to produce an artifact for those too?

See screenshot below:
Review-assisted by: Kimi K3 via `kilo-cli`

Yes we'd build 3.15t artifacts as well. Not adding yet, but I'll make sure to change the docs when we add CI changes for python3.15 here or on different PR.

…3.15

sklam

I reviewed 0591e68. The changes are solid. I cannot find any case that is a problem.

Other notes:

NOT_TAKEN appears when any conditional branching opcode occur (after any POP_JUMP_IF_):

>>> def f(x):
...     if x: return True
...     else: return False
... 
>>> import dis
>>> dis.dis(f)
  1           RESUME                   0

  2           LOAD_FAST_BORROW         0 (x)
              TO_BOOL
              POP_JUMP_IF_FALSE        3 (to L1)
              NOT_TAKEN
              LOAD_COMMON_CONSTANT     9 (True)
              RETURN_VALUE

  3   L1:     LOAD_COMMON_CONSTANT    10 (False)
              RETURN_VALUE

swap357 · 2026-08-11T00:11:15Z

I added CI changes needed for py3.15 here with 463b08b to 8408d58.

With changes, osx-arm64 and linux-aarch64 build and tests do pass with py3.15.
https://github.com/numba/numba/actions/runs/31421954123/job/93566352238?pr=10732
About CI failures with py3.15 on other platforms :

conda builders are failing because there's no numpy available on distribution yet for py3.15.
linux wheel builders are failing because CI uses manylinux2014_x86_64 and manylinux_2_28_aarch64 images to build, for which there are no numpy wheels, and when it does try to build wheel, numpy now need GCC >=10.3.
../meson.build:25:4: ERROR: Problem encountered: NumPy requires GCC >= 10.3
For this, it might be worth upgrading manylinux images on linux-64 and linux-aarch64 to newer ones.
win-64 wheel builder - MSVC needs /std:c++20 for Python 3.15 headers
(https://github.com/numba/numba/actions/runs/31421952358/job/93564657449?pr=10732)

…ystems

This reverts commit f3bd7bd.

…sed on python3.13+

…test section

swap357 · 2026-08-20T23:19:09Z

With f7e61d3, these test dependencies have been skipped on conda recipe test section for Python 3.15 until they are available -
jinja2, cffi, scipy, ipython, pyyaml, pygments, pexpect, ipykernel, psutil

swap357 · 2026-09-04T02:34:39Z

-#include "internal/pycore_call.h"
-#include "cpython/code.h"
-
-#elif (PY_MAJOR_VERSION >= 3) && (PY_MINOR_VERSION == 11)


Why is the code here moved ?

Python 3.13+ (including 3.15) uses the public PyMonitoring APIs for sys-monitoring. (see: #10578)
The moved code are internal headers are only needed for the 3.12 invoke_monitoring() path, so they are now gated under the 3.12-only block. One of those headers also conflicted with the MSVC /std:c++20 change, which is why they were moved.

swap357 · 2026-09-04T02:53:45Z

        ("3.13", "2.1"),
        ("3.14", "2.3"),
+        ("3.15", "2.5"),
    )


Why no free-threaded (3.15t) on CI build/test matrix ?

3.15t is intentionally omitted from this PR and will be added separately. From experiments on my fork (https://github.com/swap357/numba/actions/runs/33830492988/job/100892610519) looks like all build env dependencies might not have 3.15t (free-threading) support yet.

Replace index-based lookup with identity comparison (`is`) when searching for entries in the exception table. Additionally, add an assertion to verify depth consistency when merging adjacent entries.

esc

Ok, I gave this a final review and it's totally fine!

For the record, these are the 3.15 limitations, not addressed by this PR:

No 3.15t (free threading) on wheels or condas
3.15 condas have unmet dependencies because not all packages have been built out
No 3.15 win-arm64 support just yet

We are merging this now to enable 3.15 on the bulk of our officially supported platforms with the goal of fixing up the rest in subsequent PRs.

Thank you @swap357 for the patches and thank you @sklam and @stuartarchibald for the additional reviews, feedback and suggestions. ❤️

esc · 2026-09-04T14:26:36Z

FWIW: there was one CI failure on linux-64:

github.com/numba/numba/actions/runs/33847524840/job/100943453103?pr=10732

======================================================================
FAIL: test_set_num_threads_inside_guvectorize_tbb_4_threads (numba.tests.test_num_threads.TestNumThreadsBackends.test_set_num_threads_inside_guvectorize_tbb_4_threads)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.15.0-rc.2/x64/lib/python3.15/site-packages/numba/tests/test_num_threads.py", line 602, in test_template
    o, e = self.run_test_in_separate_process(injected_method, backend,
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^
                                             num_threads)
                                             ^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.15.0-rc.2/x64/lib/python3.15/site-packages/numba/tests/test_num_threads.py", line 593, in run_test_in_separate_process
    return self.run_cmd(cmdline, env_copy)
           ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.15.0-rc.2/x64/lib/python3.15/site-packages/numba/tests/test_parallel_backend.py", line 363, in run_cmd
    raise AssertionError(
        "process failed with code %s: stderr follows\n%s\n" %
        (popen.returncode, err.decode()))
AssertionError: process failed with code -11: stderr follows
_test_set_num_threads_inside_guvectorize (numba.tests.test_num_threads.TestNumThreads._test_set_num_threads_inside_guvectorize) ... ok

From OOB conversations with @stuartarchibald and @swap357 this is most likely a latent bug that has existed for years. It's probably not 3.15 specific and should not block the merge of this PR. May need to open a new issue to track it

swap357 · 2026-09-04T15:24:15Z

FWIW: there was one CI failure on linux-64:

github.com/numba/numba/actions/runs/33847524840/job/100943453103?pr=10732

======================================================================
FAIL: test_set_num_threads_inside_guvectorize_tbb_4_threads (numba.tests.test_num_threads.TestNumThreadsBackends.test_set_num_threads_inside_guvectorize_tbb_4_threads)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.15.0-rc.2/x64/lib/python3.15/site-packages/numba/tests/test_num_threads.py", line 602, in test_template
    o, e = self.run_test_in_separate_process(injected_method, backend,
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^
                                             num_threads)
                                             ^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.15.0-rc.2/x64/lib/python3.15/site-packages/numba/tests/test_num_threads.py", line 593, in run_test_in_separate_process
    return self.run_cmd(cmdline, env_copy)
           ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.15.0-rc.2/x64/lib/python3.15/site-packages/numba/tests/test_parallel_backend.py", line 363, in run_cmd
    raise AssertionError(
        "process failed with code %s: stderr follows\n%s\n" %
        (popen.returncode, err.decode()))
AssertionError: process failed with code -11: stderr follows
_test_set_num_threads_inside_guvectorize (numba.tests.test_num_threads.TestNumThreads._test_set_num_threads_inside_guvectorize) ... ok

From OOB conversations with @stuartarchibald and @swap357 this is most likely a latent bug that has existed for years. It's probably not 3.15 specific and should not block the merge of this PR. May need to open a new issue to track it

there's a related issue here - #10563.

swap357 and others added 15 commits July 23, 2026 14:59

Add Python 3.15 support

e845583

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Add Python 3.15 to supported minor versions in NB_SUPPORTED_PYTHON_MINOR

73b2666

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Extend _Py_IsFinalizing compat shim to cover Python 3.15

deb6d08

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Extend _dispatcher.cpp version guards to include Python 3.15

10aac69

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Extend _typeof.cpp pycore_setobject.h include guard to Python 3.15

c1cd82d

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Extend _helperlib.c traceback_add version guards to Python 3.15

b8011a4

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Add Python 3.15 to controlflow.py version guards

8f39631

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Add Python 3.15 to byteflow.py version guards

29fb078

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Add Python 3.15 to interpreter.py version guards

2faecae

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Add Python 3.15 to version guards across core and test files

82f3575

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

[py] avoid no op GET_ITER for py3.15+

028f9cf

[py] update byteflow.py to handle Python 3.15 changes for op_POP_ITER…

2c89e48

… and op_GET_ITER stack behavior

[py] handle all entries in dis._common_constants for LOAD_COMMON_CONS…

a40ccf1

…TANT. Python 3.15 emits this opcode for literals like -1 as well as builtins, so generalize the byteflow tracer and interpreter beyond AssertionError.

[py] fix EXTENDED_ARG test injection offset for Python 3.15 CACHE slots.

d96e633

Locate LOAD_CONST dynamically instead of assuming a fixed offset after RESUME, which overwrote CACHE and triggered a fatal interpreter error.

[py] skip/xfail known test failures on python 3.15

0fd1b2e

swap357 added the 2 - In Progress label Jul 27, 2026

swap357 added 5 commits August 2, 2026 23:49

[py] update comments for py315 changes

a360c72

[py] adapt caching tests to Python 3.15 import API (__spec__.cached i…

abcfc62

…nstead of __cached__)

[py] merge exception table entries split by NOT_TAKEN for py3.15 cond…

0591e68

…itional comprehensions

resolve flake8 errors

3970015

[py] make LOAD_COMMON_CONSTANT allowlists explicit

1a856b9

swap357 added 3 - Ready for Review and removed 2 - In Progress labels Aug 5, 2026

add release note

b65616d

swap357 marked this pull request as ready for review August 5, 2026 06:31

swap357 requested a review from sklam as a code owner August 5, 2026 06:31

swap357 requested a review from esc August 5, 2026 06:32

esc requested changes Aug 5, 2026

View reviewed changes

address review: use explicit py-version branch for op_GET_ITER on byt…

fa3221e

…eflow

address review: use explicit py-version branch on bytecode.py

6bd6783

sklam reviewed Aug 7, 2026

View reviewed changes

Comment thread numba/core/bytecode.py

swap357 added 3 commits August 10, 2026 11:59

[ci] add py315 to wheel build and test matrix

463b08b

[ci] add py315 to conda build and test matrix

e484d7e

[ci] use temporary ad-testing/label/py315 conda channel to get python…

8408d58

…3.15

sklam reviewed Aug 10, 2026

View reviewed changes

swap357 and others added 5 commits August 13, 2026 08:50

Merge branch 'main' into python-3.15

0aa12f1

update setup.py to use c++20 std for compiling c extensions on MSVC s…

f449b0a

…ystems

add permissive flag with std:c++20 for msvc extra_compile_args

f3bd7bd

Revert "add permissive flag with std:c++20 for msvc extra_compile_args"

a5066a6

This reverts commit f3bd7bd.

move internal headers to the 3.12 sys.monitoring path, they are not u…

6c6b324

…sed on python3.13+

swap357 added this to the 0.68.0rc1 milestone Aug 14, 2026

swap357 and others added 2 commits August 19, 2026 11:11

Merge branch 'main' into python-3.15

3abe965

skip numba test dependencies not available on py315 on conda receipe …

f7e61d3

…test section

Merge remote-tracking branch 'upstream/main' into python-3.15

b3a6ddf

swap357 requested a review from esc September 2, 2026 23:05

swap357 added 3 commits September 3, 2026 19:19

remove unused skip condition for Python 3.15 on support.py

cb1c25a

line wrap long condition on test_operators.py

c2dff3e

use hardcoded offset for LOAD_CONST on test_extended_arg.py

8bd2fae

swap357 commented Sep 4, 2026

View reviewed changes

use identity comparison for exception table entry merging

17781f8

Replace index-based lookup with identity comparison (`is`) when searching for entries in the exception table. Additionally, add an assertion to verify depth consistency when merging adjacent entries.

esc approved these changes Sep 4, 2026

View reviewed changes

swap357 merged commit 1979f73 into numba:main Sep 4, 2026
226 of 227 checks passed

esc mentioned this pull request Sep 10, 2026

Python 3.15 #10581

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