{"record":{"id":"c535294626df8cfa","repo":"risingwavelabs/risingwave","slug":"failed-to-read-the-4-byte-schema-id","errorCode":null,"errorMessage":"failed to read the 4-byte schema ID","messagePattern":"failed to read the 4-byte schema ID","errorType":"exception","errorClass":"WireFormatError::NoSchemaId","httpStatus":null,"severity":"error","filePath":"src/connector/src/schema/schema_registry/util.rs","lineNumber":50,"sourceCode":"            Err(e) => errs.push(e),\n        }\n    }\n    if urls.is_empty() {\n        bail_invalid_option_error!(\"no valid url provided, errs: {errs:?}\");\n    }\n    tracing::debug!(\n        \"schema registry client will use url {:?} to connect, the rest failed because: {:?}\",\n        urls,\n        errs\n    );\n    Ok(urls)\n}\n\n#[derive(Debug, thiserror::Error)]\npub enum WireFormatError {\n    #[error(\"failed to match the magic byte 0\")]\n    NoMagic,\n    #[error(\"failed to read the 4-byte schema ID\")]\n    NoSchemaId,\n    #[error(\"failed to parse message indexes\")]\n    ParseMessageIndexes,\n}\n\n/// Returns `(schema_id, payload)`\n///\n/// Refer to [Confluent schema registry wire format](https://docs.confluent.io/platform/7.6/schema-registry/fundamentals/serdes-develop/index.html#wire-format)\n///\n/// | Bytes | Area        | Description                                                                                        |\n/// |-------|-------------|----------------------------------------------------------------------------------------------------|\n/// | 0     | Magic Byte  | Confluent serialization format version number; currently always `0`.                               |\n/// | 1-4   | Schema ID   | 4-byte schema ID as returned by Schema Registry.                                                   |\n/// | 5-... | Data        | Serialized data for the specified schema format (for example, binary encoding for Avro or Protobuf.|\npub(crate) fn extract_schema_id(payload: &[u8]) -> Result<(i32, &[u8]), WireFormatError> {\n    use byteorder::{BigEndian, ReadBytesExt as _};\n\n    let mut cursor = payload;","sourceCodeStart":32,"sourceCodeEnd":68,"githubUrl":"https://github.com/risingwavelabs/risingwave/blob/6469eb736d691e8e9b8a419a57edd6429ca77417/src/connector/src/schema/schema_registry/util.rs#L32-L68","documentation":"WireFormatError::NoSchemaId is thrown when the decoder reads the magic byte 0 successfully but fails to read the subsequent 4-byte big-endian schema ID from the payload. The message is too short or truncated at the schema ID position.","triggerScenarios":"Parsing a message that has the magic byte 0 but fewer than 5 total bytes needed for magic + schema ID — truncated or corrupted Kafka messages, or custom producers writing a bare magic byte without the ID.","commonSituations":"Byte-truncated messages from broken producers, manually crafted test data missing the schema ID, compaction/serialization bugs in a custom producer.","solutions":["Verify message length: it must be at least 5 bytes (1 magic + 4 schema ID).","Fix the upstream producer to emit the full Confluent envelope (magic byte, 4-byte schema ID, payload).","Inspect with a consumer dumping raw bytes (e.g. kafkacat -C ... -D %s) to find truncated messages.","Reproduce/refresh the affected records if they were corrupted in transit."],"exampleFix":"// before\nlet id = i32::from_be_bytes(bytes[1..5].try_into()?);\n// after\nif bytes.len() < 5 {\n    return Err(WireFormatError::NoSchemaId);\n}\nlet id = i32::from_be_bytes(bytes[1..5].try_into()?);","handlingStrategy":"type-guard","validationCode":"fn envelope_complete(bytes: &[u8]) -> bool {\n    bytes.first() == Some(&0) && bytes.len() >= 5\n}","typeGuard":"fn has_schema_id(b: &[u8]) -> bool { b.len() >= 5 }","tryCatchPattern":"match parse_wire_format(bytes) {\n    Ok((id, payload)) => decode(id, payload),\n    Err(WireFormatError::NoSchemaId) => {\n        tracing::warn!(\"truncated envelope; skipping message\");\n        skip();\n    }\n    Err(e) => return Err(e.into()),\n}","preventionTips":["Check messages are >= 5 bytes before parsing.","Fix upstream producers to emit full magic+schema-id envelopes.","Monitor for producer bugs that truncate payloads.","Add consumer-side metrics on short messages."],"tags":["kafka","wire-format","schema-registry"],"backgroundTag":"unexpected-response-shape","analyzedSha":"6469eb736d691e8e9b8a419a57edd6429ca77417","analyzedAt":"2026-09-11T21:06:21.487Z","contentChangedAt":"2026-09-11T21:06:21.487Z","schemaVersion":2},"datasetVersion":"2026-09-14T16:17:12.679Z"}