strict_optional=False makes checking scripts using xarray to fail #9437
Description
🐛 Bug Report
When using mypy with strict_optional = False in the config file or using the --no-strict-optional flag in the terminal to check a file using the xarray package, it fails with an scary INTERNAL ERROR message.
This might be a bug better suited for the xarray team, but thought to check with you first.
To Reproduce
Write a python script just importing xarray:
import xarray as xrAnd check it with mypy using mypy --no-strict-optional script.py
Expected Behavior
Everything works fine and I get: Success: no issues found in 1 source file . This is indeed the behavior if the --no-strict-optional flag is NOT used.
Actual Behavior
I get the following output (personal info replaced by XXXXX):
/XXXXX/venv/lib/python3.7/site-packages/xarray/core/dataarray.py:2001: error: INTERNAL ERROR -- Please try using mypy master on Github:
https://mypy.rtfd.io/en/latest/common_issues.html#using-a-development-mypy-build
If this issue continues with mypy master, please report a bug at https://github.com/python/mypy/issues
version: 0.782
/XXXXX/venv/lib/python3.7/site-packages/xarray/core/dataarray.py:2001: : note: please use --show-traceback to print a traceback when reporting a bug
I've tried also the development version of mypy, as sugested, with identical results, and also used the --show-traceback option, with results in:
/XXXXX/venv/lib/python3.7/site-packages/xarray/core/dataarray.py:2001: error: INTERNAL ERROR -- Please try using mypy master on Github:
https://mypy.rtfd.io/en/latest/common_issues.html#using-a-development-mypy-build
Please report a bug at https://github.com/python/mypy/issues
version: 0.782
Traceback (most recent call last):
File "mypy/checker.py", line 401, in accept
File "mypy/nodes.py", line 1129, in accept
File "mypy/checker.py", line 3437, in visit_for_stmt
File "mypy/checker.py", line 3470, in analyze_iterable_item_type
File "mypy/checkexpr.py", line 2345, in check_method_call_by_name
File "mypy/checkmember.py", line 126, in analyze_member_access
File "mypy/checkmember.py", line 143, in _analyze_member_access
File "mypy/checkmember.py", line 225, in analyze_instance_member_access
File "mypy/checkmember.py", line 376, in analyze_member_var_access
File "mypy/checkmember.py", line 578, in analyze_var
File "mypy/meet.py", line 50, in meet_types
File "mypy/types.py", line 794, in accept
File "mypy/meet.py", line 497, in visit_instance
File "mypy/meet.py", line 647, in meet
File "mypy/meet.py", line 50, in meet_types
File "mypy/types.py", line 1347, in accept
File "mypy/meet.py", line 584, in visit_tuple_type
File "mypy/typeops.py", line 44, in tuple_fallback
File "mypy/join.py", line 531, in join_type_list
File "mypy/join.py", line 105, in join_types
File "mypy/types.py", line 794, in accept
File "mypy/join.py", line 158, in visit_instance
File "mypy/join.py", line 371, in join_instances
File "mypy/subtypes.py", line 143, in is_subtype_ignoring_tvars
File "mypy/subtypes.py", line 93, in is_subtype
File "mypy/subtypes.py", line 135, in _is_subtype
File "mypy/types.py", line 794, in accept
File "mypy/subtypes.py", line 259, in visit_instance
File "mypy/subtypes.py", line 541, in is_protocol_implementation
File "mypy/subtypes.py", line 93, in is_subtype
File "mypy/subtypes.py", line 135, in _is_subtype
File "mypy/types.py", line 1786, in accept
File "mypy/subtypes.py", line 459, in visit_partial_type
RuntimeError:
/XXXXX/venv/lib/python3.7/site-packages/xarray/core/dataarray.py:2001: : note: use --pdb to drop into pdb
Your Environment
- Mypy version used: 0.782
- xarray version: 0.16.0
- Mypy command-line flags:
--no-strict-optional - Mypy configuration options from
mypy.ini(and other config files):strict_optional = Falsehas the same effect. - Python version used: 3.7.4
- Operating system and version: Mac OS Catalina 10.15.6