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Typing Error due to return type of astropy.units.core.def_unit #14632
Description
Description
Hi,
It appears that forms like 10 << u.m gives error in type checking (pyright in my case):
The alternative form 10 << u.Unit("m") works fine.
I believe the issue is due to the computed return type of the def_unit function, which is a union of three: Unit, IrreducibleUnit, and (H0) -> Equivalency. The last item does not have the __rlshift__ operator defined.
Expected behavior
No error in type checking.
How to Reproduce
pip install pyright astropy- Create pyright configuration file
pyrightconfig.json:
{
"include": [
"./test_astropy_unit_type.py"
],
"useLibraryCodeForTypes": true,
}- Create test python file
test_astropy_unit_type.py:
import astropy.units as u
a = 10.0 << u.m- Run
pyrightand see the following output:
...
Found 1 source file
pyright 1.1.303
/home/ma/mnt/W-Ma/toltec/random_stuff/test_astropy_unit_type.py
/home/ma/mnt/W-Ma/toltec/random_stuff/test_astropy_unit_type.py:3:5 - error: Operator "<<" not supported for types "float" and "Unit | IrreducibleUnit | ((H0: Unknown | None = None) -> Equivalency)"
Operator "<<" not supported for types "float" and "(H0: Unknown | None = None) -> Equivalency" (reportGeneralTypeIssues)
1 error, 0 warnings, 0 informations
Completed in 1.203sec
Versions
Linux-5.15.85-penguins-rule-x86_64-with-glibc2.35
Python 3.10.6 (main, Mar 10 2023, 10:55:28) [GCC 11.3.0]
astropy 5.2.2
Pyright 1.1.303
Activity
pllim commentedon Apr 14, 2023
I don't think we have full typing support yet but maybe @mhvk or @nstarman can clarify.
mhvk commentedon Apr 14, 2023
Indeed, astropy has only minimal typing support so far. That said, I'm not sure why
(H0) -> Equivalencyis an output type. That seems wrong. Maybe @nstarman has more of a clue...nstarman commentedon Apr 15, 2023
Yes, I frequently encounter this. In the absence of actual type hints pyright tries (and fails) to infer the types. Mypy has a different approach and labels this Any. Short of adding either type support or type stubs I don't think there's a good solution.
neutrinoceros commentedon Jan 25, 2024
Type hints are now actively being worked on. @nstarman do you know if this can be closed or linked to any of your existing PRs ?
nstarman commentedon Jan 25, 2024
Not yet. we haven't type hinted anything really in
units.