Major Description
https://github.com/apache/spark/pull/40510 introduce `message StorageLevel` to `base.proto`, but if we try to import `base.proto` in `catalog.proto` to reuse `StorageLevel` in `message CacheTable` and run `build/sbt "connect-common/compile" to compile, there will be following message in compile log:
spark/connect/base.proto:23:1: File recursively imports itself: spark/connect/base.proto -> spark/connect/commands.proto -> spark/connect/relations.proto -> spark/connect/catalog.proto -> spark/connect/base.proto spark/connect/catalog.proto:22:1: Import "spark/connect/base.proto" was not found or had errors. spark/connect/catalog.proto:144:12: "spark.connect.DataType" seems to be defined in "spark/connect/types.proto", which is not imported by "spark/connect/catalog.proto". To use it here, please add the necessary import. spark/connect/catalog.proto:161:12: "spark.connect.DataType" seems to be defined in "spark/connect/types.proto", which is not imported by "spark/connect/catalog.proto". To use it here, please add the necessary import. spark/connect/relations.proto:25:1: Import "spark/connect/catalog.proto" was not found or had errors. spark/connect/relations.proto:84:5: "Catalog" is not defined. spark/connect/commands.proto:22:1: Import "spark/connect/relations.proto" was not found or had errors. spark/connect/commands.proto:63:3: "Relation" is not defined. spark/connect/commands.proto:81:3: "Relation" is not defined. spark/connect/commands.proto:142:3: "Relation" is not defined. spark/connect/base.proto:23:1: Import "spark/connect/commands.proto" was not found or had errors. spark/connect/base.proto:25:1: Import "spark/connect/relations.proto" was not found or had errors. ....
So we should move `message StorageLevel` from `base.proto` to a separate file to avoid this issue