Previously, the auto-configuration for DataSource initialization and
the properties used to configure it were part of the general
DataSource auto-configuration and properties.
This commit moves the auto-configuration of DataSource initialization
out into a separate top-level auto-configuration class. Similarly,
the properties for configuring DataSource initialization have been
moved from `spring.datasource.*` into `spring.sql.init.*`.
The old initialization-related `spring.datasource.*` properties have
been deprecated but can still be used. When they are used, they new,
separate initialization auto-configuration will back off. In other
words, the initialization related `spring.datasource.*` properties
and the `spring.sql.init.*` properties cannot be used in combination.
Closes gh-25323
Previously, DataSource initialization was triggered via a
BeanPostProcessor or a schema created event from JPA. This caused
numerous problems with circular dependencies, bean lifecycle, etc and
added significant complexity.
This commit reworks DataSource initialization to remove the use of a
BeanPostProcessor entirely. In its place, DataSource initialization is
now driven by an InitializingBean with dependency relationships
between beans ensuring that initialization has been performed before
the DataSource is used. This aligns with the approach that's worked
well with Flyway and Liquibase.
More changes are planned to further simplify DataSource initialization.
The changes in this commit are a foundation for those changes. Any new
public API in this commit is highly likely to change before the next
GA.
Fixes gh-13042
Fixes gh-23736
Refine the package restructure started in 91ccc23462 to help provide
a solid foundation for code snippets. This commit renames many of the
classes so that they no longer end in `Example`. It also removes some
of the inner types that were previously used. Many tag comments have
also been moved to ensure that `import` statements are available in
the docs.
Closes gh-25089
Restructure the packages in `spring-boot-docs` so that they mirror
the documentation sections. There are now three main packages:
`springbootfeatures`, `productionreadyfeatures` and `howto`. Each
of the main packages has a subpackage named after the section headings.
Example code now uses consistent `// tag::` names and imports are
applied using `[tag=*]` whenever possible.
Test snippets have been moved to `src/main/java` so that only a single
import attribute needs to be defined.
Closes gh-25089
