Warn when a fixture for a different loop_scope is requested #1514

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1. seifertm

   added this to the v1.5 milestone on Jul 21, 2026
2. seifertm

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   Feature

   issue type on Jul 21, 2026
3. nicoddemus

   added a commit that references this issue on Jul 21, 2026

   Add PytestAsyncioLoopScopeMismatchWarning for loop-scope mismatches (p…

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4. tjkuson commented on Jul 24, 2026

   

   tjkuson

   on Jul 24, 2026

   Last edited by tjkuson

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   Emitting a warning when pytest 'jumps' a loop scope during the execution of a test and its fixtures makes a lot of sense to me. However, users of pytest-asyncio currently can configure the default loop scope for fixtures and tests separately. I think it also follows that it is almost certain that configuring the default loop scopes for fixtures and tests to be different is likely a user error as well.

   To avoid user confusion, I think it would make sense to consolidate these configs to a single asyncio_default_loop_scope that controls the default loop scope for both fixtures and tests. We could then deprecate the current configurations and point people to use the new one. The way this would be communicated to users could be along the lines of:

   pytest-asyncio defaults to running each test function and any async fixture it requests in its own function-scoped event loop. If most of your async tests use async fixtures that use a wider loop scope (e.g., a session-scoped async fixture that requires a session-scoped event loop), you should configure the default loop scope accordingly. You can control the loop scope on individual test functions and fixtures using the pytest.mark.asyncio marker and pytest_asyncio.fixture decorator.