No type checking for thread local variables?

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#2,388 4 comments 5 reactions 0 assignees View on GitHub

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
python
Domain
devtools

Research direction

Start by reproducing both snippets with --disallow-untyped-defs and --disallow-untyped-calls, then inspect how mypy handles attributes on threading.local(). Compare the unannotated mixed-key assignments with the rejected attribute annotation; done means the intended checking and annotation behavior is covered by regression tests.

Written by the indexing model from the issue text.

Description

feature priority-2-low

The following type checks without errors even though I am running with "--disallow-untyped-defs --disallow-untyped-calls".

import threading
_parameter_values = threading.local()
_parameter_values.data = {}
_parameter_values.data[3] = "hello"
_parameter_values.data["hello"] = 3

and if I deliberately try to add annotations:

import threading
_parameter_values = threading.local()
_parameter_values.data: Dict[int, str] = {}
_parameter_values.data[3] = "hello"

then I get the following error:
error: Type cannot be declared in assignment to non-self attribute

Dominant language
Python
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