CodSpeed Performance Report

Merging#11581 willnot alter performance

_{ComparingYassinNouh21:fix/prevent-infinite-recursion-in (901b43c) withmain (a2846da)}

Summary

✅ 46 untouched benchmarks

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
pydantic
main.py					1180-1188
Project Total

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Thanks for the contribution, I still need to think on this one. As mentioned in the CPythonissue, we might want to consider the recursion error as expected.

I also won't be surprised if the approach here doesn't work as expected for more complex recursive cases.

@Viicos Thanks for reviewing the PR. While Python's core behavior treats the RecursionError as expected for circular references, I believe Pydantic should offer more robust handling as a high-level library:

1. The solution uses ContextVar to efficiently track object pairs during comparison, breaking recursion cycles.
2. It returns True when cycles are detected, consistent with Golang's approach

I've tested this with various recursive scenarios (self-references, mutual references, and deep cycles) and found it works reliably.

Can you add CodSpeed benchmarks in a separate PR (eq checks for different nestings)? To then see in this PR that this wont degrade eq checking perf. This is now adding a bunch of set allocs and lookups to every eq operation. It might not be worth fixing the issue if the perf takes a hit for everyone. Considering how corner case it is which also exists in Python itself.

Discussed today with the team, indeed would be great to assess the potential performance hit here. The linked issue also doesn't have much demand, and it feels like using context vars for this is a bit too much.

@Viicos I understand the concern about performance. Can I add CodSpeed benchmarks to measure the impact—would that help in evaluating this further? Also, would making this behavior configurable be a good compromise? Let me know your thoughts!