fix: use minimal integer encoding and decode fixint bytes#13
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Encoder now routes all integer types through encode_int/encode_uint so the smallest format that fits is always selected (positive/negative fixint, u8/u16/u32/u64, i8/i16/i32/i64), per the MessagePack spec's minimal-encoding requirement. Default config flips positive_int_unsigned to true so non-negative values use the more compact unsigned family. Decoder gains match arms for positive fixint (0x00-0x7f) and negative fixint (0xe0-0xff) in both decode_integer and decode_to_json, fixing inability to decode output from spec-compliant implementations (Python, Rust, Go) and from this library's own corrected encoder. Test assertions updated to spec-compliant bytes. Reported in vlang/v#26644.
This was referenced May 26, 2026
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Summary
Fixes three interop-breaking bugs in the integer encode/decode paths, reported in vlang/v#26644.
encode(0)producedd2 00 00 00 00instead of00. The genericencode[T]()dispatcher bypassed the existingencode_int/encode_uintfunctions (which already implement minimal encoding) and called fixed-width helpers directly. Now all integer types route throughencode_int/encode_uint. The missingi32case is also added.positive_int_unsigneddefaulted tofalse. Non-negative values 128–255 took the signed branch and encoded as 3-byte int16 instead of 2-byte uint8. Default config now sets it totrue.decode_integeranddecode_to_jsonhad nomatcharms for0x00–0x7for0xe0–0xff, so any value in-32..127encoded by a spec-compliant library (Python, Rust, Go) — or by this library after the encoder fix — could not be decoded. Both functions now handle the fixint ranges.encode_test.vassertions are updated to the spec-compliant minimal bytes.Test plan
v test .— all 3 test files pass (decode, encode, decode_to_json)encode(0)→00,encode(42)→2a,encode(127)→7fencode(-32)→e0,encode(-123)→d0 85,encode(-1)→ffencode(200)→cc c8(uint8, not signed int16)encode([1,2,3])→93 01 02 03decode(encode(x))for fixint and uint8 ranges2a,00,fb,e0,ff)