RuntimeError: cannot cache function

[WanderingStar]

I've been getting this error (and broken spectrogram links):

birdcage-birdcage_backend-1   | [2023-09-03 19:32:10,419] ERROR in app: Exception on /api/spectrogram/thumb/43626abc-3a49-465f-aa87-18513ff810fd.mp3.png [GET]
birdcage-birdcage_backend-1   | Traceback (most recent call last):
birdcage-birdcage_backend-1   |   File "/usr/local/lib/python3.10/site-packages/flask/app.py", line 2190, in wsgi_app
birdcage-birdcage_backend-1   |     response = self.full_dispatch_request()
birdcage-birdcage_backend-1   |   File "/usr/local/lib/python3.10/site-packages/flask/app.py", line 1486, in full_dispatch_request
birdcage-birdcage_backend-1   |     rv = self.handle_user_exception(e)
birdcage-birdcage_backend-1   |   File "/usr/local/lib/python3.10/site-packages/flask_cors/extension.py", line 165, in wrapped_function
birdcage-birdcage_backend-1   |     return cors_after_request(app.make_response(f(*args, **kwargs)))
birdcage-birdcage_backend-1   |   File "/usr/local/lib/python3.10/site-packages/flask/app.py", line 1484, in full_dispatch_request
birdcage-birdcage_backend-1   |     rv = self.dispatch_request()
birdcage-birdcage_backend-1   |   File "/usr/local/lib/python3.10/site-packages/flask/app.py", line 1469, in dispatch_request
birdcage-birdcage_backend-1   |     return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)
birdcage-birdcage_backend-1   |   File "/app/views/audio_files.py", line 79, in serve_thumb_spectrogram
birdcage-birdcage_backend-1   |     image_binary = create_spectrogram(audio_path, height=70)
birdcage-birdcage_backend-1   |   File "/app/views/audio_files.py", line 20, in create_spectrogram
birdcage-birdcage_backend-1   |     clip, sample_rate = librosa.load(fn_audio, sr=None)
birdcage-birdcage_backend-1   |   File "/usr/local/lib/python3.10/site-packages/lazy_loader/__init__.py", line 77, in __getattr__
birdcage-birdcage_backend-1   |     attr = getattr(submod, name)
birdcage-birdcage_backend-1   |   File "/usr/local/lib/python3.10/site-packages/lazy_loader/__init__.py", line 76, in __getattr__
birdcage-birdcage_backend-1   |     submod = importlib.import_module(submod_path)
birdcage-birdcage_backend-1   |   File "/usr/local/lib/python3.10/importlib/__init__.py", line 126, in import_module
birdcage-birdcage_backend-1   |     return _bootstrap._gcd_import(name[level:], package, level)
birdcage-birdcage_backend-1   |   File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
birdcage-birdcage_backend-1   |   File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
birdcage-birdcage_backend-1   |   File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
birdcage-birdcage_backend-1   |   File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
birdcage-birdcage_backend-1   |   File "<frozen importlib._bootstrap_external>", line 883, in exec_module
birdcage-birdcage_backend-1   |   File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
birdcage-birdcage_backend-1   |   File "/usr/local/lib/python3.10/site-packages/librosa/core/audio.py", line 19, in <module>
birdcage-birdcage_backend-1   |     from .convert import frames_to_samples, time_to_samples
birdcage-birdcage_backend-1   |   File "/usr/local/lib/python3.10/site-packages/librosa/core/convert.py", line 7, in <module>
birdcage-birdcage_backend-1   |     from . import notation
birdcage-birdcage_backend-1   |   File "/usr/local/lib/python3.10/site-packages/librosa/core/notation.py", line 800, in <module>
birdcage-birdcage_backend-1   |     def __o_fold(d):
birdcage-birdcage_backend-1   |   File "/usr/local/lib/python3.10/site-packages/numba/core/decorators.py", line 234, in wrapper
birdcage-birdcage_backend-1   |     disp.enable_caching()
birdcage-birdcage_backend-1   |   File "/usr/local/lib/python3.10/site-packages/numba/core/dispatcher.py", line 863, in enable_caching
birdcage-birdcage_backend-1   |     self._cache = FunctionCache(self.py_func)
birdcage-birdcage_backend-1   |   File "/usr/local/lib/python3.10/site-packages/numba/core/caching.py", line 601, in __init__
birdcage-birdcage_backend-1   |     self._impl = self._impl_class(py_func)
birdcage-birdcage_backend-1   |   File "/usr/local/lib/python3.10/site-packages/numba/core/caching.py", line 337, in __init__
birdcage-birdcage_backend-1   |     raise RuntimeError("cannot cache function %r: no locator available "
birdcage-birdcage_backend-1   | RuntimeError: cannot cache function '__o_fold': no locator available for file '/usr/local/lib/python3.10/site-packages/librosa/core/notation.py'

I've been able to fix it with this, based on this SO answer: https://stackoverflow.com/questions/59290386/runtimeerror-at-cannot-cache-function-shear-dense-no-locator-available-fo

  birdcage_backend:
    environment:
      NUMBA_CACHE_DIR: /tmp

But I'm not sure whether anything changed to cause it in the first place.