`_encode_variable_length_prefix(..).unwrap()` in `write_length_encoded`

[ckeshava]

Description

BinarySerializer::write_length_encoded unwraps the result of _encode_variable_length_prefix(&byte_object.len()). When the encoded field's length exceeds MAX_LENGTH_VALUE (918,744 bytes), the helper returns an Err, and the unwrap panics. The source already has // TODO Handle unwrap better.

Location

• src/core/binarycodec/binary_wrappers.rs#L451

Impact / Severity

Medium — Panic on large field. A Blob, AccountID list, Memos field, or STArray exceeding 918 KB panics the encoder.

Adversarial Agent Notes

Verdict: ACCEPT.

[e-desouza]

Fix in PR #343. Key lines:

• binary_wrappers.rs:394 — trait signature
• binary_wrappers.rs:444 — impl

What changed:

write_length_encoded — propagates error instead of panicking:

// before (infallible, panics on oversized input)
fn write_length_encoded(&mut self, value: &[u8], encode_value: bool) -> &Self {
    let length_prefix = _encode_variable_length_prefix(&byte_object.len()).unwrap(); // TODO Handle unwrap better
    ...
    self
}

// after (returns Result, propagates via ?)
fn write_length_encoded(&mut self, value: &[u8], encode_value: bool) -> XRPLCoreResult<&Self> {
    let length_prefix = _encode_variable_length_prefix(&byte_object.len())?;
    ...
    Ok(self)
}

Same change applied to write_field_and_value. All callers updated to propagate with ?.