Ensure that @LiquibaseDataSource is preferred to “normal” DataSource

Closes gh-6604

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/liquibase/LiquibaseAutoConfiguration.java

@@ -116,12 +116,12 @@ public class LiquibaseAutoConfiguration {
 		}
 
 		private DataSource getDataSource() {
-			if (this.properties.getUrl() == null) {
-				return this.dataSource;
-			}
-			else if (this.liquibaseDataSource != null) {
+			if (this.liquibaseDataSource != null) {
 				return this.liquibaseDataSource;
 			}
+			else if (this.properties.getUrl() == null) {
+				return this.dataSource;
+			}
 			return DataSourceBuilder.create().url(this.properties.getUrl())
 					.username(this.properties.getUser())
 					.password(this.properties.getPassword()).build();

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/liquibase/LiquibaseDataSource.java

@@ -25,8 +25,8 @@ import java.lang.annotation.Target;
 import org.springframework.beans.factory.annotation.Qualifier;
 
 /**
- * Qualifier annotation for a DataSource to be injected in to Liquibase. If used for a second
- * data source, the other (main) one would normally be marked as {@code @Primary}.
+ * Qualifier annotation for a DataSource to be injected in to Liquibase. If used for a
+ * second data source, the other (main) one would normally be marked as {@code @Primary}.
  *
  * @author Eddú Meléndez
  * @since 1.4.1

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/liquibase/LiquibaseAutoConfigurationTests.java

@@ -38,6 +38,7 @@ import org.springframework.boot.test.util.EnvironmentTestUtils;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Primary;
 import org.springframework.test.util.ReflectionTestUtils;
 import org.springframework.util.FileCopyUtils;
 
@@ -254,12 +255,20 @@ public class LiquibaseAutoConfigurationTests {
 				PropertyPlaceholderAutoConfiguration.class);
 		this.context.refresh();
 		SpringLiquibase liquibase = this.context.getBean(SpringLiquibase.class);
-		assertThat(liquibase.getDataSource()).isNotNull();
+		assertThat(liquibase.getDataSource())
+				.isEqualTo(this.context.getBean("liquibaseDataSource"));
 	}
 
 	@Configuration
 	static class LiquibaseDataSourceConfiguration {
 
+		@Bean
+		@Primary
+		public DataSource normalDataSource() {
+			return DataSourceBuilder.create().url("jdbc:hsqldb:mem:normal").username("sa")
+					.build();
+		}
+
 		@LiquibaseDataSource
 		@Bean
 		public DataSource liquibaseDataSource() {