fixtures: fix closure computation with indirect override chains#13789
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bluetech merged 2 commits intopytest-dev:mainfrom Oct 10, 2025
Merged
fixtures: fix closure computation with indirect override chains#13789bluetech merged 2 commits intopytest-dev:mainfrom
bluetech merged 2 commits intopytest-dev:mainfrom
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Explicitly test a couple more scenarios. One of the tests doesn't currently pass so marked xfail.
Continuation of 72ae3db. The previous fix was a minimal change to make the existing code at least consider fixtures overrides, and handles the common case (direct override chains), but still wasn't correct, as it didn't handle override chains involving an intermediary (not the overridden) fixture. To make this work, the algorithm needs to change. Now instead of a simple breadth-first search, we do a depth-first search, which more closely simulates the runtime behavior, and allows us the to check the "stack" of fixtures so we can use the correct fixture index (depth in the override chain). This is more expensive but should be OK. Refs pytest-dev#13773.
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Going to merge this, because it finishes the work in #13774 for pytest 9.0, and I have some work planned which depends on it. I also noticed that in #11234 @sadra-barikbin had the same idea (changing fixturemanager::getfixtureclosure algo from BFS to DFS), though didn't get to implement it. So must have some merit :) |
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… from overridden fixtures As the xfail'ed test `test_fixture_closure_with_overrides_and_parametrization` demonstrates, adding any direct parametrization causes the statically computed fixture closure to omit transitive dependencies from overridden (but still requested) fixtures. (The dynamic algorithm does get it right). The `prune_dependency_tree()` function did not account for overridden fixtures properly (only checked `-1`). Make it share the core recursive DFS traversal used by `getfixtureclosure()`, which already fixed a similar problem (pytest-dev#13789). An alternative solution is to replace `prune_dependency_tree` wholesale with another call to `getfixtureclosure`, as proposed in PR pytest-dev#11243, however it's somewhat harder to get working, so let's go with this solution for now. Fix pytest-dev#14248
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Continuation of #13774.
The previous fix was a minimal change to make the existing code at least consider fixtures overrides, and handles the common case (direct override chains), but still wasn't correct, as it didn't handle override chains involving an intermediary (not the overridden) fixture.
To make this work, the algorithm needs to change. Now instead of a simple breadth-first search, we do a depth-first search, which more closely simulates the runtime behavior, and allows us the to check the "stack" of fixtures so we can use the correct fixture index (depth in the override chain).
This is more expensive but should be OK.
Refs #13773.