Fix IndexError in CacheOrder.pop() on empty cache#1054
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lyonsno wants to merge 2 commits intoml-explore:mainfrom
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Fix IndexError in CacheOrder.pop() on empty cache#1054lyonsno wants to merge 2 commits intoml-explore:mainfrom
lyonsno wants to merge 2 commits intoml-explore:mainfrom
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`trim_to(n_bytes=0)` loops on `self._n_bytes > n_bytes` without checking whether the CacheOrder has entries left to evict. When both internal deques are empty, `0 >= 0` selects the regular deque and `popleft()` raises `IndexError`. Guard `trim_to`'s byte-eviction loop with `len(self._lru) > 0` and add an explicit empty check in `CacheOrder.pop()` for a clearer error message if a caller ever bypasses the guard. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Summary
LRUPromptCache.trim_to(n_bytes=0)can crash withIndexErrorif the byte-eviction loop runs after_n_byteshas drifted out of sync with the actual cache contents. Thewhile self._n_bytes > n_bytesloop had no guard against an emptyCacheOrder, sopop()could callpopleft()on an empty deque.len(self._lru) > 0guard on the byte-eviction loop intrim_to, and an explicit empty check inCacheOrder.pop()for a clearer error if a future caller bypasses the guard.Test plan
test_trim_to_zero_bytes_on_empty_cache—trim_to(n_bytes=0)on empty cache no longer raisestest_trim_to_zero_bytes_evicts_all—trim_to(n_bytes=0)on populated cache evicts all entries cleanlyFound during production testing on Qwen3.5-122B (M2 Ultra 128GB) while reviewing #1042.
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