No more stack overrun on pathological tree queries!#381
Merged
RossNordby merged 1 commit intomasterfrom Aug 29, 2025
Merged
Conversation
RossNordby
added
bug
breaking-change
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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
Historically, a few queries on
Treeassumed a maximum possible depth. It was guarded by debug asserts. It was not guarded at runtime.Simultaneously, there were pathological cases where the tree could become more like a linked list.
That's bad!
#380 and #375 fixed the so-far-observed paths to degeneracy in a tree, but having a stack overrun at runtime should not be a thing that's logically accessible!
With the unfortunate side effect of requiring
BufferPools in a whole lotta places, the tree query paths will no longer explode in release mode if the tree gets really badly screwed up. Queries still default to using stack allocations, so the performance impact of this change is minimal (just a bunch of trivially predictable branches).