[develop] VisiData occassionally gets stuck when importing requests

[anjakefala]

On develop branch, with Python v3.9, occassionally VisiData will fail to progress when loading from a url:

anja@kefala:git/visidata ‹develop*›$ vd https://visidata.org/usage.tsv
saul.pw/VisiData v2.12dev
loaded visidatarc

And you have to Ctrl+C to get the following stacktrace:

^CTraceback (most recent call last):
  File "/home/anja/anaconda3/envs/vd39/bin/vd", line 7, in <module>
    exec(compile(f.read(), __file__, 'exec'))
  File "/home/anja/git/visidata/bin/vd", line 6, in <module>
    visidata.main.vd_cli()
  File "/home/anja/git/visidata/visidata/main.py", line 372, in vd_cli
    rc = main_vd()
  File "/home/anja/git/visidata/visidata/main.py", line 294, in main_vd
    vs = vd.openSource(p, create=True, **opts) or vd.fail(f'could not open {p}')
  File "/home/anja/git/visidata/visidata/_open.py", line 145, in openSource
    vs = vd.openPath(Path(p), filetype=filetype)  # convert to Path and recurse
  File "/home/anja/git/visidata/visidata/_open.py", line 82, in openPath
    return openfunc(p, filetype=filetype)
  File "/home/anja/git/visidata/visidata/loaders/http.py", line 21, in openurl_http
    requests = vd.importExternal('requests')
  File "/home/anja/git/visidata/visidata/settings.py", line 459, in importExternal
    m = importlib.import_module(modname)
  File "/home/anja/anaconda3/envs/vd39/lib/python3.9/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1030, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
  File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 680, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 850, in exec_module
  File "<frozen importlib._bootstrap>", line 228, in _call_with_frames_removed
  File "/home/anja/anaconda3/envs/vd39/lib/python3.9/site-packages/requests/__init__.py", line 43, in <module>
    import urllib3
  File "/home/anja/anaconda3/envs/vd39/lib/python3.9/site-packages/urllib3/__init__.py", line 11, in <module>
    from . import exceptions
  File "/home/anja/anaconda3/envs/vd39/lib/python3.9/site-packages/urllib3/exceptions.py", line 3, in <module>
    from .packages.six.moves.http_client import IncompleteRead as httplib_IncompleteRead
  File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
  File "<frozen importlib._bootstrap>", line 982, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 925, in _find_spec
  File "/home/anja/anaconda3/envs/vd39/lib/python3.9/site-packages/urllib3/packages/six.py", line 192, in find_spec
    return spec_from_loader(fullname, self)
  File "<frozen importlib._bootstrap>", line 431, in spec_from_loader
  File "/home/anja/anaconda3/envs/vd39/lib/python3.9/site-packages/urllib3/packages/six.py", line 222, in is_package
    return hasattr(self.__get_module(fullname), "__path__")
  File "/home/anja/anaconda3/envs/vd39/lib/python3.9/site-packages/urllib3/packages/six.py", line 121, in __getattr__
    _module = self._resolve()
  File "/home/anja/anaconda3/envs/vd39/lib/python3.9/site-packages/urllib3/packages/six.py", line 118, in _resolve
    return _import_module(self.mod)
  File "/home/anja/anaconda3/envs/vd39/lib/python3.9/site-packages/urllib3/packages/six.py", line 87, in _import_module
    __import__(name)
  File "<frozen importlib._bootstrap>", line 211, in _lock_unlock_module
  File "<frozen importlib._bootstrap>", line 107, in acquire
KeyboardInterrupt

Our current hypothesis is that this is the relevant bug: python/cpython#91351

Conceivably, other loaders with importlib dependencies that also have dependencies might be affected. It is just currently reproducibly coming up for open_http.

[anjakefala]

Update: I have seen it come up in Python v3.8 and v3.10.

[anjakefala]

This seems to now be fixed! Seems to be the mixing of import and importExternal =)