fix: mask left shifts in numeric fast path - #1096
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stephenamar-db merged 2 commits intoJul 30, 2026
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Motivation: Jsonnet interprets shift counts modulo 64, but the numeric fast path validated left shifts using the unmasked count. Expressions routed through outer arithmetic could therefore fail even when the generic evaluator succeeded. Modification: Normalize non-negative left-shift counts modulo 64 before both overflow validation and execution, and add regressions for counts 64, 65, and 128. Result: Numeric fast-path behavior now matches the generic evaluator, go-jsonnet, jrsonnet, and the Jsonnet specification without changing valid count-65 behavior. References: - databricks#1096 - https://jsonnet.org/ref/spec.html
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Motivation: The original tests only covered zero and positive left operands. The overflow check uses math.abs(ll), so negative values exercise a distinct code path that should be regression-protected. Modification: Add assertions for (-1)<<64, (-2)<<65, (-3)<<128 through the numeric fast path (via * 1). Result: Negative operand behavior is now locked in.
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Motivation
Jsonnet specifies shift counts are modulo 64. The numeric fast path (
visitBinaryOpAsDouble) checked overflow with the unmasked count while the JVM masked the actual shift, making results path-dependent:(1 << 64) * 1incorrectly errored instead of returning1.Modification
rr % 64before the overflow check in the numeric fast path.Result
(1 << 64) * 1111(1 << 65) * 12222(1 << 128) * 1111(0 << 128) * 1000((1 << 64) + 0) * 1111Full matrix (JVM/JS/Wasm/Native) +
checkFormatpassed.References
builtinShiftLmodulo-64