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Intermittent test failure on iOS during test_interpreters stress test: RuntimeError: Failed to import encodings module #131485

Closed as duplicate
Closed as duplicate
Intermittent test failure on iOS during test_interpreters stress test: RuntimeError: Failed to import encodings module#131485
Labels
3.13only security fixes3.14bugs and security fixestopic-subinterpreterstype-bugAn unexpected behavior, bug, or error

Description

@freakboy3742
freakboy3742
opened on Mar 20, 2025

Bug report

Bug description:

We've seen intermittent failures on the iOS buildbot during the execution of the test_interpreters test:

...
test_create_many_sequential (test.test_interpreters.test_stress.StressTests.test_create_many_sequential) ... ok
test_create_many_threaded (test.test_interpreters.test_stress.StressTests.test_create_many_threaded) ... ok
test_many_threads_running_interp_in_other_interp (test.test_interpreters.test_stress.StressTests.test_many_threads_running_interp_in_other_interp) ... Warning -- Uncaught thread exception: InterpreterError
Exception in thread Thread-1571 (run):
RuntimeError: Failed to import encodings module

During handling of the above exception, another exception occurred:

interpreters.InterpreterError: sub-interpreter creation failed

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/buildbot/Library/Developer/XCTestDevices/4F6EA510-4EA0-4706-8B1F-020FE958C08F/data/Containers/Bundle/Application/DBFDCCFF-85B7-4B66-9B7D-D1A7666166D0/iOSTestbed.app/python/lib/python3.14/threading.py", line 1054, in _bootstrap_inner
    self.run()    
    ~~~~~~~~^^  
  File "/Users/buildbot/Library/Developer/XCTestDevices/4F6EA510-4EA0-4706-8B1F-020FE958C08F/data/Containers/Bundle/Application/DBFDCCFF-85B7-4B66-9B7D-D1A7666166D0/iOSTestbed.app/python/lib/python3.14/threading.py", line 996, in run
    self._target(*self._args, **self._kwargs)    
    ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
  File "/Users/buildbot/Library/Developer/XCTestDevices/4F6EA510-4EA0-4706-8B1F-020FE958C08F/data/Containers/Bundle/Application/DBFDCCFF-85B7-4B66-9B7D-D1A7666166D0/iOSTestbed.app/python/lib/python3.14/test/test_interpreters/test_stress.py", line 47, in run
    interp = interpreters.create()  
  File "/Users/buildbot/Library/Developer/XCTestDevices/4F6EA510-4EA0-4706-8B1F-020FE958C08F/data/Containers/Bundle/Application/DBFDCCFF-85B7-4B66-9B7D-D1A7666166D0/iOSTestbed.app/python/lib/python3.14/test/support/interpreters/__init__.py", line 76, in create    
    id = _interpreters.create(reqrefs=True)
interpreters.InterpreterError: interpreter creation failed
ok

----------------------------------------------------------------------
Ran 152 tests in 7.483s
OK (skipped=14)
0:05:31 load avg: 4.70 [248/486/1] test_interpreters failed (env changed)

The test itself passes seems to pass; the failure that is reported is a change in environment. The test passes on a re-run.

There have been 6 examples of this in the last 2 months:

It has also been observed in 3.13

It's not clear to me if this is an iOS issue (falling apart under the stress), or an issue with the underlying subinterpreter setup that iOS is able to (intermittently) expose. The "Failed to import encodings module" is the bit that gives me pause - There's no diagnostics on why the import failed, but that sort of error would be consistent with a path not being fully configured. It clearly is configured (in the normal case at least), but I'm wondering if having multiple threads start simultaneously could be exposing a leak where one thread thinks something has been configured but another thread is still initialising.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Other

Activity

  1. freakboy3742
    added
    3.13only security fixes
    3.14bugs and security fixes
    OS-ios
    topic-subinterpreters
    type-bugAn unexpected behavior, bug, or error
    on Mar 20, 2025
  2. github-project-automation
    added this to Subinterpreterson Mar 20, 2025
  3. github-project-automation
    moved this to Todo in Subinterpreterson Mar 20, 2025
  4. vstinner
    changed the title [-]Intermittent test failure on iOS during `test_interpreters` stress test[/-] [+]Intermittent test failure on iOS during `test_interpreters` stress test: RuntimeError: Failed to import encodings module[/+] on Mar 20, 2025

  5. vstinner commented on Mar 20, 2025

    @vstinner
    vstinner
    on Mar 20, 2025
    Member

    I'm able to reproduce the issue on Linux with the command ./python -m test test_interpreters.test_stress -u all -v -F -j2 --fail-env-changed:

    0:00:49 load avg: 7.92 [ 16/1] test_interpreters.test_stress worker non-zero exit code (Exit code -6 (SIGABRT))
test_create_many_sequential (test.test_interpreters.test_stress.StressTests.test_create_many_sequential) ... ok
test_create_many_threaded (test.test_interpreters.test_stress.StressTests.test_create_many_threaded) ... Warning -- Uncaught thread exception: InterpreterError
Exception in thread Thread-134 (task):
RuntimeError: Failed to import encodings module

During handling of the above exception, another exception occurred:

interpreters.InterpreterError: sub-interpreter creation failed

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/vstinner/python/main/Lib/threading.py", line 1054, in _bootstrap_inner
    self.run()
    ~~~~~~~~^^
  File "/home/vstinner/python/main/Lib/threading.py", line 996, in run
    self._target(*self._args, **self._kwargs)
    ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/vstinner/python/main/Lib/test/test_interpreters/test_stress.py", line 30, in task
    interp = interpreters.create()
  File "/home/vstinner/python/main/Lib/test/support/interpreters/__init__.py", line 76, in create
    id = _interpreters.create(reqrefs=True)
interpreters.InterpreterError: interpreter creation failed
ok
test_many_threads_running_interp_in_other_interp (test.test_interpreters.test_stress.StressTests.test_many_threads_running_interp_in_other_interp) ... ok

----------------------------------------------------------------------
Ran 3 tests in 6.056s

OK
python: Objects/typeobject.c:301: managed_static_type_state_clear: Assertion `!_PyRuntime.types.managed_static.types[full_index].interp_count' failed.
  6. freakboy3742
    removed
    OS-ios
    on Mar 20, 2025

  7. freakboy3742 commented on Mar 20, 2025

    @freakboy3742
    freakboy3742
    on Mar 20, 2025
    ContributorAuthor

    Thanks @vstinner - that seems to confirm it's not an iOS error, just something iOS is good at exposing for some reason.

  8. ZeroIntensity commented on Mar 20, 2025

    @ZeroIntensity
    ZeroIntensity
    on Mar 20, 2025
    Member

    Yeah, this is a known issue. See also #127108 and #129824. Static types are a bit racy right now; I've been working on a PR to fix it over the past week or two, but due to some burnout and lack of time, it's not going to be ready for at least a few more days.

  9. freakboy3742 commented on Mar 20, 2025

    @freakboy3742
    freakboy3742
    on Mar 20, 2025
    ContributorAuthor

    In which case, I'll close this in favor of #127108, and copy over the useful details. Thanks for letting me know about the other tickets.

  10. freakboy3742
    closed this as completedon Mar 20, 2025
  11. github-project-automation
    moved this from Todo to Done in Subinterpreterson Mar 20, 2025
  12. serhiy-storchaka
    closed this as a duplicateof test_interpreters: test_create_many_threaded() failed on FreeBSD: log: RuntimeError: interpreter creation failed #109700 on Jul 7, 2025
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