fix: reset vector class to FLAT in ResetWithSameType to fix prepared stmt null json panic#23864
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mergify[bot] merged 6 commits intomatrixorigin:mainfrom Mar 17, 2026
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…stmt null json panic (matrixorigin#23859) When a prepared statement inserts NULL into a JSON column multiple times, the second execution panics with 'index out of range [0] with length 0' in ByteJson.Unmarshal during SELECT. Root cause: FunctionExpressionExecutor.doFold() calls ToConst() on the result vector after constant folding. On the second execution, PreExtendAndReset() calls ResetWithSameType() which clears nsp but preserves the CONSTANT class. When FunctionResult.AppendBytes(nil, true) is called on a CONSTANT vector, it skips setting the null marker, resulting in a non-null empty byte slice being stored instead of NULL. Fix: Reset vector class to FLAT in ResetWithSameType(), so the vector is in a clean state for re-population. doFold() will call ToConst() again after evaluation if needed.
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What type of PR is this?
Which issue(s) this PR fixes:
issue #23859
What this PR does / why we need it:
When a prepared statement inserts NULL into a JSON column multiple times, the second execution causes a panic during SELECT:
Reproduce:
Root cause:
FunctionExpressionExecutor.doFold()callsToConst()on the result vector after constant folding. On the second execution,PreExtendAndReset()callsResetWithSameType()which clears nsp (null bitmap) but preserves the CONSTANT class. WhenFunctionResult.AppendBytes(nil, true)is called on a CONSTANT vector, it skips setting the null marker entirely, resulting in a non-null empty byte slice being stored instead of NULL.Fix: Reset vector class to FLAT in
ResetWithSameType(), so the vector is in a clean state for re-population.doFold()will callToConst()again after evaluation if needed.