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fix(commons): clear LRUCache pointers on eviction of last item - #5295
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When LRUCache is configured with maxSize 0, adding an item triggers immediate eviction. If the evicted item has no newer neighbor, shift() was not clearing the leastRecentlyUsed and mostRecentlyUsed pointers. Subsequent additions would incorrectly link onto these stale pointers, causing the cache to permanently retain one stale entry. Clear both pointers in shift() when the evicted item is the only one in the cache. Also add test coverage for multiple additions with maxSize 0. Closes aws-powertools#5290
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svozza
approved these changes
May 26, 2026
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Merged! |
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Summary
Changes
When LRUCache is configured with maxSize 0, adding any item triggers immediate eviction. When the evicted item has no newer neighbor, shift() was not clearing the leastRecentlyUsed and mostRecentlyUsed pointers. Subsequent additions would incorrectly link onto these stale pointers, causing the cache to permanently retain one stale entry.
This change sets both pointers to undefined in shift() when the evicted item is the only one in the cache.
Issue number: closes #5290
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