Fix UBSan: negation of signed INT_MIN before cast to unsigned#96979
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alexey-milovidov merged 2 commits intomasterfrom Feb 15, 2026
Merged
Fix UBSan: negation of signed INT_MIN before cast to unsigned#96979alexey-milovidov merged 2 commits intomasterfrom
alexey-milovidov merged 2 commits intomasterfrom
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…igned The expression `static_cast<UInt64>(-idx)` performs negation in signed domain first, which is undefined behavior when `idx` equals `INT_MIN` (e.g., -2147483648 for Int32). The fix reverses the operations: `-static_cast<UInt64>(idx)` casts to unsigned first, then negates in well-defined unsigned arithmetic. Fixed in `arrayElement.cpp` (the actual UBSan failure from the AST fuzzer) and preventively in `Planner.cpp`, `InterpreterSelectQuery.cpp`, `WindowTransform.cpp`, and `TemporaryDataOnDisk.cpp`. https://s3.amazonaws.com/clickhouse-test-reports/json.html?REF=master&sha=36a049a7f14c6fbc7e0eb33dc32ec94514ceaa7c&name_0=MasterCI&name_1=AST%20fuzzer%20%28amd_ubsan%29 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Summary
arrayElementwherestatic_cast<UInt64>(-idx)negatesINT_MINin signed domain (UB). Changed to-static_cast<UInt64>(idx)which negates in unsigned domain.Planner,InterpreterSelectQuery,WindowTransform, andTemporaryDataOnDisk.toInt32(-2147483648)array index.AST fuzzer (amd_ubsan) CI report: https://s3.amazonaws.com/clickhouse-test-reports/json.html?REF=master&sha=36a049a7f14c6fbc7e0eb33dc32ec94514ceaa7c&name_0=MasterCI&name_1=AST%20fuzzer%20%28amd_ubsan%29
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