Thanks for spotting the potential problems here, @quaff, but the proposed changes are moving things in the wrong direction.

The auto-configuration of IntegrationDataSourceScriptDatabaseInitializer will already back off without spring-boot-jdbc:

Given this, the implementation dependency on spring-boot-sql in unnecessary. We're also missing a test. I've opened #46244.

The auto-configuration of QuartzDataSourceScriptDatabaseInitializer does not back off without spring-boot-jdbc and it should. I've opened #46243 for this.

@wilkinsona What about BatchDataSourceScriptDatabaseInitializer and JdbcSessionDataSourceScriptDatabaseInitializer, should spring-boot-jdbc be optional dependency also?

No, I don't think so. Boot's auto-configuration for Spring Batch requires JDBC as it always sets up the JDBC-based job store. As such, a required dependency on spring-boot-jdbc is OK there. Similarly, spring-boot-session-jdbc is a separate module that requires JDBC so a required dependency on spring-boot-jdbc is OK there too.

Spring Batch requires JDBC as it always sets up the JDBC-based job store.

Spring Batch supports to set up the MongoDB-based job store now, see spring-projects/spring-batch#877

We're aware of that but it doesn't affect the accuracy of what I said about Boot's auto-configuration for Batch. As and when we add auto-configuration for the MongoDB-based store, this situation will change.