First, thank you for looking into it! There is a thing caught my eye:
> The writtenSchema cannot add required fields, … As far as I know, the required fields were removed in Protocol Buffers v3. I see proto3 usage in existing schema registry tests: https://github.com/apache/pulsar/blob/6704f12104219611164aa2bb5bbdfc929613f1bf/pulsar-broker/src/test/proto/ProtobufSchemaTest.proto#L19 https://github.com/apache/pulsar/blob/1ea4ad814f5f30b8c371db2a86626cd568ace553/pulsar-sql/presto-pulsar/src/test/java/org/apache/pulsar/sql/presto/decoder/protobufnative/TestMsg.proto#L19 I see proto2 usage in the proposed changes: https://github.com/apache/pulsar/pull/19566/files#diff-f2f7463a3df6dc6366f3ee3a416707e655f0d5b8d2ae623a3f05a209c1d6ec88R19 https://github.com/apache/pulsar/pull/19566/files#diff-f2f7463a3df6dc6366f3ee3a416707e655f0d5b8d2ae623a3f05a209c1d6ec88R19 Also, I’m not sure about this: > int32, uint32, int64, uint64, and bool are all compatible – this means you > can change a field from one of these types to another without breaking > forwards- or backwards-compatibility. It leads to JS/PHP-like implicit conversions if I understand it right. From: SiNan Liu <liusinan1...@gmail.com> Date: Sunday, February 19, 2023 at 1:59 PM To: dev@pulsar.apache.org <dev@pulsar.apache.org> Subject: [DISCUSS] PIP-246: Improved PROTOBUF_NATIVE schema compatibility checks without using avro-protobuf Hi all, I made a PIP to discuss: https://github.com/apache/pulsar/issues/19565. We can talk about the current design here. Especially for the field type change check rules, please give your valuable advice. Thanks, Sinan
