[ty] Fix flaky constraint set rendering #20653
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
dcreager
added
internal
dcreager
requested review from
AlexWaygood,
carljm and
sharkdp
as code owners
Contributor
Diagnostic diff on typing conformance testsNo changes detected when running ty on typing conformance tests ✅ |
Contributor
|
ibraheemdev
approved these changes
Sep 30, 2025
Contributor
|
Merging this, as I'm seeing it on some other PRs too. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This doesn't seem to be flaky in the sense of tests failing non-deterministically, but they are flaky in the sense of unrelated changes causing testing failures from the clauses of a constraint set being rendered in different orders. This flakiness is because we're using Salsa IDs to determine the order in which typevars appear in a constraint set BDD, and those IDs are assigned non-deterministically.
The fix is ham-fisted but effective: sort the constraints in each clause, and the clauses in each set, as part of the rendering process. Constraint sets are only rendered in our test cases, so we don't need to over-optimize this.