can1357/oh-my-pi · error · Error

Unsupported wire type ${entryWireType} in map entry

Error message

Unsupported wire type ${entryWireType} in map entry

What it means

Thrown while decoding a protobuf map<K,V> field: an entry's tag carries a wire type outside the supported set, so the entry cannot be parsed. As with the top-level wire-type error, this indicates corrupt, truncated, or non-protobuf bytes rather than a normal code path.

Source

Thrown at packages/catalog/src/discovery/protobuf.ts:410

				}
				writer.tag(number, 2);
				writer.lengthDelimited(entry.finish());
			}
		},
		decode(message, reader, wireType, _fieldNumber) {
			assertWireType(wireType, 2);
			const target = mapField(message, name);
			const limit = reader.uint32();
			const end = reader.pos + limit;
			let entryKey = "";
			let entryValue: unknown = valCodec.defaultValue;

			while (reader.pos < end) {
				const tag = reader.uint32();
				const entryNumber = tag >>> 3;
				const entryWireType = tag & 7;
				if (!isWireType(entryWireType)) {
					throw new Error(`Unsupported wire type ${entryWireType} in map entry`);
				}
				if (entryNumber === 1) {
					assertWireType(entryWireType, key.wireType);
					entryKey = requireString(key.decode(reader));
				} else if (entryNumber === 2) {
					assertWireType(entryWireType, valCodec.wireType);
					entryValue = valCodec.decode(reader);
				} else {
					reader.skip(entryWireType);
				}
			}

			target[entryKey] = entryValue;
		},
		toJson(message, output) {
			const input = Reflect.get(message, name);
			if (!isMessageObject(input)) return;
			const mapOutput: { [key: string]: JsonValue } = Object.create(null);

View on GitHub (pinned to 9690622007)

Solutions

1. Confirm the buffer slice passed to the map decoder starts exactly at the entry boundary (check length-delimited offsets).
2. Regenerate/re-sync the codec against the producer's current .proto — key/value field types may have changed.
3. Validate the raw payload with `protoc --decode_raw` to see the actual entry structure.
4. Wrap decoding with a clear error path so corrupt upstream payloads surface as data errors, not decoder crashes.

Example fix

// before: slicing bytes manually
const entry = decodeMapEntry(buf.subarray(offset));
// after: honor the length-delimited prefix
const len = buf[offset++]; // varint length as encoded
const entry = decodeMapEntry(buf.subarray(offset, offset + len));

null

null

try {
  const msg = codec.decode(bytes);
} catch (err) {
  if (err.message.includes("Unsupported wire type") && err.message.includes("map entry")) {
    throw new Error(`map field bytes incompatible with codec schema — regenerate codec from current .proto`);
  }
  throw err;
}

When it happens

Trigger: decode of a map field where the embedded entry message's bytes are malformed — wrong offset into the entry, bytes from a different schema version where field 1/2 changed, or garbage bytes misread as an entry tag.

Common situations: Server/producer wrote map entries with a newer schema (changed key/value types); decoding a slice that starts mid-entry; response intercepted/modified by a proxy.

Related errors

• Unsupported protobuf wire type ${wireType} at byte ${reader.
• Unsupported wire type ${wireType} in Struct
• Unsupported wire type ${wireType} in ListValue
• invalid byte sequence: {:02x?}
• Unknown oneof field ${fieldNumber}

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/52223f8fbc8ca348. Report an issue: GitHub.