fix: Guard backwards-array walker against non-InputByte sentinels#248
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fix: Guard backwards-array walker against non-InputByte sentinels#248
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The extractNextJavaCharacterFromInputCharactersForBackwardsArrays walker and isContinuationByte assumed every element in the InputCharacter[] array is an InputByte. For wildcard patterns, the array contains InputWildcard sentinels (the leading/trailing '*'). When the walker iterated past the last continuation byte of a multi-byte UTF-8 character into a trailing InputWildcard, InputByte.cast() threw ClassCastException. Trigger: suffix rule (hasSuffix > 0) + two wildcard rules with the same multi-byte value on the same JSON path. The second wildcard compile walks existing state with hasIndeterminatePrefix=true, reaching the backwards walker via canReuseNextByteState -> doMultipleTransitionsConvergeForInputByte. Fix: return false from isContinuationByte for non-InputByte elements, and break from the backwards walker loop on non-InputByte elements. Both changes treat non-byte sentinels as multi-byte sequence boundaries. Includes 8 regression tests covering: minimal repro, various multi-byte code points, many-rule interleaving, all add-order permutations, add-delete-add, stress (50 duplicate wildcards), and matching correctness for every scenario. sim: https://taskei.amazon.dev/tasks/P421369483
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The extractNextJavaCharacterFromInputCharactersForBackwardsArrays walker and isContinuationByte assumed every element in the InputCharacter[] array is an InputByte. For wildcard patterns, the array contains InputWildcard sentinels (the leading/trailing '*'). When the walker iterated past the last continuation byte of a multi-byte UTF-8 character into a trailing InputWildcard, InputByte.cast() threw ClassCastException.
Trigger: suffix rule (hasSuffix > 0) + two wildcard rules with the same multi-byte value on the same JSON path. The second wildcard compile walks existing state with hasIndeterminatePrefix=true, reaching the backwards walker via canReuseNextByteState -> doMultipleTransitionsConvergeForInputByte.
Fix: return false from isContinuationByte for non-InputByte elements, and break from the backwards walker loop on non-InputByte elements. Both changes treat non-byte sentinels as multi-byte sequence boundaries.
Includes 8 regression tests covering: minimal repro, various multi-byte code points, many-rule interleaving, all add-order permutations, add-delete-add, stress (50 duplicate wildcards), and matching correctness for every scenario.
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