Move DataSource init auto-config out of DataSourceAutoConfiguration

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

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/liquibase/LiquibaseEndpointTests.java

@@ -18,7 +18,9 @@ package org.springframework.boot.actuate.liquibase;
 
 import java.sql.Connection;
 import java.sql.SQLException;
+import java.util.Arrays;
 import java.util.Map;
+import java.util.UUID;
 
 import javax.sql.DataSource;
 
@@ -30,6 +32,8 @@ import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
 import org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration;
 import org.springframework.boot.jdbc.EmbeddedDatabaseConnection;
+import org.springframework.boot.jdbc.init.DataSourceInitializationSettings;
+import org.springframework.boot.jdbc.init.ScriptDataSourceInitializer;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
@@ -75,10 +79,8 @@ class LiquibaseEndpointTests {
 
 	@Test
 	void invokeWithCustomSchema() {
-		this.contextRunner.withUserConfiguration(Config.class)
-				.withPropertyValues("spring.liquibase.default-schema=CUSTOMSCHEMA",
-						"spring.datasource.schema=classpath:/db/create-custom-schema.sql")
-				.run((context) -> {
+		this.contextRunner.withUserConfiguration(Config.class, DataSourceWithSchemaConfiguration.class)
+				.withPropertyValues("spring.liquibase.default-schema=CUSTOMSCHEMA").run((context) -> {
 					Map<String, LiquibaseBean> liquibaseBeans = context.getBean(LiquibaseEndpoint.class)
 							.liquibaseBeans().getContexts().get(context.getId()).getLiquibaseBeans();
 					assertThat(liquibaseBeans.get("liquibase").getChangeSets()).hasSize(1);
@@ -138,6 +140,23 @@ class LiquibaseEndpointTests {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static class DataSourceWithSchemaConfiguration {
+
+		@Bean
+		DataSource dataSource() {
+			DataSource dataSource = new EmbeddedDatabaseBuilder()
+					.setType(EmbeddedDatabaseConnection.get(getClass().getClassLoader()).getType())
+					.setName(UUID.randomUUID().toString()).build();
+			DataSourceInitializationSettings settings = new DataSourceInitializationSettings();
+			settings.setSchemaLocations(Arrays.asList("classpath:/db/create-custom-schema.sql"));
+			ScriptDataSourceInitializer initializer = new ScriptDataSourceInitializer(dataSource, settings);
+			initializer.initializeDatabase();
+			return dataSource;
+		}
+
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	static class MultipleDataSourceLiquibaseConfiguration {