fix(utilities): lossless guard + unsigned BigInt parser - #58
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`toCppIntegerB` called `BigInt::Int64Value(&lossless)` but never checked the `lossless` flag. A BigInt outside the int64_t range (e.g. bit 63 of a uint64 accidentally set on the JS side) silently wrapped — the helper documented as a parser was acting as a truncating cast. Throw on `!lossless`. `toCppIntegerB` is also the wrong parser for fields the C++ side stores as uint64 (bitsets, profile flags): a NEGATIVE BigInt (-1n) is lossless as int64 and wraps to 0xFFFFFFFFFFFFFFFF when assigned to a uint64 destination — the same high-bit injection the lossless check was supposed to block. Add a dedicated `toCppUnsignedIntegerB` (and matching optional wrapper `maybeNonemptyUintB`) that rejects negative BigInts via `BigInt::ToWords()` sign-bit inspection BEFORE the `Uint64Value` conversion. Callers that need to store into uint64 should migrate to the unsigned variant in a follow-up commit; this change only adds the helpers + tightens the existing int64 helper. No behaviour change on the existing call sites unless they pass a BigInt outside int64 range, in which case they were already storing the wrong value. Signed-off-by: Claude Perrin <klodr@users.noreply.github.com>
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Adds a
losslessguard ontoCppIntegerB(rejects silent truncation past int64 range) and a newtoCppUnsignedIntegerB/maybeNonemptyUintBpair that uses BigInt::ToWords to detect the sign bit (so a JS-1ndoesn't silently wrap to0xFFFFFFFFFFFFFFFFwhen assigned to a uint64 field like a bitset).Test plan
toCppUnsignedIntegerBthrows on negative BigInttoCppIntegerBthrows on values outside int64 range