test: Add regression tests for BTreeIndex infinite loop with undefined keys by KyleAMathews · Pull Request #1191 · TanStack/db

KyleAMathews · 2026-01-27T18:00:47Z

🎯 Changes

This PR adds comprehensive regression tests for GitHub issue #1186, which describes an infinite loop in BTreeIndex.takeInternal when using orderBy() and limit() on collections containing items with undefined indexed values.

The test suite includes:

Basic tests for take() and takeReversed() with undefined indexed values
Tests mixing undefined and defined indexed values
Tests with multiple items sharing the same undefined key
Full end-to-end tests reproducing the exact scenario from issue Infinite loop in BTreeIndex.takeInternal when using orderBy and limit with undefined indexed values #1186 using live queries with orderBy and limit
Tests combining where, orderBy, and limit with undefined values

All tests include a 5-second timeout to catch infinite loops during test execution.

Root Cause (documented in test comments):
When nextHigherPair(undefined) is called, it returns the minimum pair from the B-tree. If that minimum key is itself undefined, the method returns [undefined, undefined]. After processing, the code sets key = pair[0] (which is undefined) and calls nextHigherPair(undefined) again, returning the same pair and creating an infinite loop.

✅ Checklist

I have followed the steps in the Contributing guide.
I have tested this code locally with pnpm test:pr.

🚀 Release Impact

This change affects published code, and I have generated a changeset.
This change is docs/CI/dev-only (no release).

Note: This is a test-only addition that documents the bug for future reference and validation once the underlying issue is fixed.

https://claude.ai/code/session_01RKBKXMoKVe1hSXGy3VVEFo

…lues (issue #1186) This test demonstrates the infinite loop bug that occurs when calling take() on a BTreeIndex containing items with undefined indexed values. The bug is in takeInternal() where nextHigherPair(undefined) returns the minimum pair [undefined, undefined], then key is set to pair[0] (undefined), causing the same pair to be returned infinitely since the while condition (pair !== undefined) is always true for arrays. https://claude.ai/code/session_01RKBKXMoKVe1hSXGy3VVEFo

changeset-bot · 2026-01-27T18:00:51Z

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pkg-pr-new · 2026-01-27T18:03:58Z

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@tanstack/angular-db

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commit: 3028e19

github-actions · 2026-01-27T18:04:36Z

Size Change: 0 B

Total Size: 90.9 kB

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github-actions · 2026-01-27T18:05:14Z

Size Change: 0 B

Total Size: 3.7 kB

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ci: apply automated fixes

ca5ad65

Remove broken tests

3028e19

KyleAMathews mentioned this pull request Jan 29, 2026

test: add comprehensive tests for BTreeIndex undefined value handling #1200

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test: Add regression tests for BTreeIndex infinite loop with undefined keys#1191

test: Add regression tests for BTreeIndex infinite loop with undefined keys#1191
KyleAMathews wants to merge 3 commits intomainfrom
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KyleAMathews commented Jan 27, 2026

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