Fix "retry_on_error" type annotation

[armicron]

When a list of classes (not instances) is assigned to RedisSettings.retry_on_error, mypy finds an error:

$ make mypy mypy arq arq/poc_annotations.py:5: error: List item 0 has incompatible type "type[ConnectionError]"; expected "Exception" [list-item] Found 1 error in 1 file (checked 13 source files) make: *** [Makefile:46: mypy] Error 1 

Redis library for the similar parameter has the type annotation Optional[List[Type[Exception]]] (source)

How to reproduce:
create a file arq/poc_annotations.py

from arq.connections import RedisSettings from redis.exceptions import ConnectionError settings = RedisSettings(retry_on_error=[ConnectionError])

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.47%. Comparing base (94cd878) to head (ae148a0).
Report is 11 commits behind head on main.

Additional details and impacted files

@@ Coverage Diff @@ ## main #446 +/- ## ========================================== + Coverage 96.27% 96.47% +0.19%  ========================================== Files 11 11 Lines 1074 1078 +4 Branches 209 190 -19 ========================================== + Hits 1034 1040 +6  Misses 19 19 + Partials 21 19 -2 

Files	Coverage Δ
arq/connections.py	89.93% <100.00%> (-0.13%)	⬇️

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[ivorpeles]

Ran into this as well, would really like to see this merged. Can further confirm that if you pass in instances mypy is satisfied but my code breaks.

Even in the test code for arq the correct types are passed, even though this isn't detected by CI:
https://github.com/samuelcolvin/arq/blob/1315583f170512fc63622af0200a2855e057a58d/tests/conftest.py#L58