Stop GetRange's range check overflowing for large counts - #68
Merged
Merged
Conversation
`startIndex + count` overflowed to a negative number when count was large, so the guard passed. ContiguousCollection then tried to allocate an int.MaxValue array, and the List-backed collections threw ArgumentException instead of the documented ArgumentOutOfRangeException. Compare count against `Count - startIndex`, which cannot overflow. Fixes #66 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_012Hhb8knddbu4LRSs2uu9jR
|
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
2 participants
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
Fixes #66
Problem
GetRangeinContiguousCollection,InsertionOrderCollectionandOrderedCollectioncheckedstartIndex + count > Count. For a largecount, the sum overflows to a negative number and the guard passes:ContiguousCollectionallocated anint.MaxValuearray and threwOutOfMemoryException.List<T>-backed collections threwArgumentExceptionfromList<T>.GetRange, not the documentedArgumentOutOfRangeException.Fix
All three collections now check
count > Count - startIndex. This comparison cannot overflow because both values are already known to be non-negative.GetRange(Count, 0)still returns an empty collection (#59).Tests
GetRange_CountOverflowingStartIndex_ThrowsArgumentOutOfRangeExceptionis new in all three test classes. It callsGetRange(1, int.MaxValue).GetRange_ZeroCountAtEnd_ReturnsEmptyis added forContiguousCollectionandInsertionOrderCollection.OrderedCollectionalready had it.With the fix reverted, the 3 overflow tests fail. With it, the full suite passes (378/378).
This PR is independent of #63, #64 and #67; all of them branch from
main.🤖 Generated with Claude Code
https://claude.ai/code/session_012Hhb8knddbu4LRSs2uu9jR
Generated by Claude Code