Repository navigation
Crash during cache serialization when checking select projects in mypy_primer #19844
Description
Crash Report
I haven't been able to reproduce this locally yet, but it seems to be occurring consistently when running mypy_primer in the CI. Examples: #19832 (comment), #19073 (comment), #19486 (comment)
Common factors:
- Occurs when checking the projects
scipy-stubsandAutoSplit - Traceback ending with
Error serializing zipimport.
See brianschubert#4 for the full output from a primer run.
Traceback
Traceback (most recent call last):
File "/tmp/mypy_primer/mypy_old/venv/bin/mypy", line 7, in <module>
sys.exit(console_entry())
~~~~~~~~~~~~~^^
File "/tmp/mypy_primer/mypy_old/venv/lib/python3.13/site-packages/mypy/__main__.py", line 15, in console_entry
main()
~~~~^^
File "/tmp/mypy_primer/mypy_old/venv/lib/python3.13/site-packages/mypy/main.py", line 127, in main
res, messages, blockers = run_build(sources, options, fscache, t0, stdout, stderr)
~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/tmp/mypy_primer/mypy_old/venv/lib/python3.13/site-packages/mypy/main.py", line 211, in run_build
res = build.build(sources, options, None, flush_errors, fscache, stdout, stderr)
File "/tmp/mypy_primer/mypy_old/venv/lib/python3.13/site-packages/mypy/build.py", line 196, in build
result = _build(
sources, options, alt_lib_path, flush_errors, fscache, stdout, stderr, extra_plugins
)
File "/tmp/mypy_primer/mypy_old/venv/lib/python3.13/site-packages/mypy/build.py", line 272, in _build
graph = dispatch(sources, manager, stdout)
File "/tmp/mypy_primer/mypy_old/venv/lib/python3.13/site-packages/mypy/build.py", line 2946, in dispatch
process_graph(graph, manager)
~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
File "/tmp/mypy_primer/mypy_old/venv/lib/python3.13/site-packages/mypy/build.py", line 3346, in process_graph
process_stale_scc(graph, scc, manager)
~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^
File "/tmp/mypy_primer/mypy_old/venv/lib/python3.13/site-packages/mypy/build.py", line 3475, in process_stale_scc
meta_tuples[id] = graph[id].write_cache()
~~~~~~~~~~~~~~~~~~~~~^^
File "/tmp/mypy_primer/mypy_old/venv/lib/python3.13/site-packages/mypy/build.py", line 2493, in write_cache
data = Buffer()
File "/tmp/mypy_primer/mypy_old/venv/lib/python3.13/site-packages/mypy/cache.py", line 28, in __init__
raise NotImplementedError
NotImplementedError
Error serializing zipimport
Activity
brianschubert commentedon Sep 13, 2025
cc @ilevkivskyi
ilevkivskyi commentedon Sep 13, 2025
--fixed-format-cacheis not officially supported for interpreted mypy yet (see release notes). If you really want to use it you can runpip install -U mypyc/lib-rt(from mypy repo root).ilevkivskyi commentedon Sep 13, 2025
Oh I guess this is because those projects are using
--fixed-format-cache. I guess @hauntsaninja you will need to add that command tomypy_primer. It may actually be beneficial in general, since this will detect effects of changes inlib-rtby a PR.ilevkivskyi commentedon Sep 13, 2025
(to clear this needs to be run only once per venv)
NotImplementedError#19861 as a duplicate of this issuebrianschubert commentedon Sep 16, 2025
Reopening for now for visibility until there’s a workaround for mypy_primer
Install librt in mypy_primer (python#19925)