BoundaryML/baml · error

body record omitted log metadata

Error message

body record omitted log metadata

What it means

When decoding a bex_events event stream, a body record (an event body) arrived without the required log metadata (value_ref/event envelope fields). file_record_from_proto only produces a FileRecord when a preceding metadata record established the log context; otherwise it returns InvalidData. This protects the reader from assembling bodies that cannot be attributed to any log event.

Source

Thrown at baml_language/crates/bex_events/src/value/read.rs:103

            return Err(io::Error::new(
                io::ErrorKind::InvalidData,
                "value record mixed capture loss metadata with body metadata",
            ));
        }
        return Ok(ValueFileRecord::CaptureLoss(loss.try_into()?));
    }
    let metadata = record.metadata.ok_or_else(|| {
        io::Error::new(io::ErrorKind::InvalidData, "value record omitted metadata")
    })?;
    if let Some(log_event) = record.log_event {
        return Ok(ValueFileRecord::LogEvent(LogRecord {
            value_ref: metadata.try_into()?,
            body: record.body,
            blob_ref: record.blob.map(TryInto::try_into).transpose()?,
            event: log_event.try_into()?,
        }));
    }
    Err(io::Error::new(
        io::ErrorKind::InvalidData,
        "body record omitted log metadata",
    ))
}

#[cfg(test)]
mod tests {
    use prost::Message as _;

    use crate::{
        ids::BoundaryId,
        value::{
            LogEventRecord, LogRecord, ValueCodec, ValueRef,
            encode::{encode_header, encode_log_event},
            pb,
        },
    };

View on GitHub (pinned to bd85ce9dee)

Solutions

1. Regenerate or re-export the trace file from a healthy source; the file is missing its metadata record and cannot be repaired by the reader
2. Verify the producer and consumer bex_events versions match — a newer writer may order records differently
3. Check that the file was not truncated in transfer (compare sizes/checksums with the origin)
4. If reading a partial stream, skip to the next complete metadata+body pair instead of the orphaned body

Example fix

// before
let record = read_bamlvalue_from_bytes(&buf)?; // panics pipeline on orphaned body
// after
match read_bamlvalue_from_bytes(&buf) {
    Ok(record) => emit(record),
    Err(e) if e.kind() == io::ErrorKind::InvalidData => skip_corrupt_chunk(),
    Err(e) => return Err(e),
}

fn has_log_metadata(record: &RawRecord) -> bool { record.metadata.is_some() }

fn is_valid_body_record(r: &FileRecord) -> bool { r.event.is_some() && r.value_ref.is_some() }

match read_bamlvalue_from_bytes(&buf) { Ok(r) => Some(r), Err(e) if e.kind() == io::ErrorKind::InvalidData => { log::warn!("skipping orphaned body record: {e}"); None }, Err(e) => return Err(e) }

When it happens

Trigger: Calling read_bamlvalue_from_bytes on a stream where a body record appears before its corresponding ValueMetadataV1 record, or where the metadata record was dropped/truncated/corrupted by the writer.

Common situations: Truncated or partially-written trace files (process crash mid-write), hand-edited or externally-trimmed event logs, or a writer-version that emits records in an order this reader version does not expect.

Related errors

• value metadata omitted codec
• value metadata omitted availability
• original size does not fit usize
• retained size does not fit usize
• blob size does not fit usize

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/a45b19e818b65f0f. Report an issue: GitHub.