Merge branch '2.6.x' into 2.7.x

Closes gh-29680

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootJarIntegrationTests-classesFromASecondarySourceSetCanBeIncludedInTheArchive.gradle

@@ -0,0 +1,15 @@
+plugins {
+	id 'java'
+	id 'org.springframework.boot' version '{version}'
+}
+
+sourceSets {
+	secondary
+	main {
+		runtimeClasspath += secondary.output
+	}
+}
+
+bootJar {
+	mainClass = 'com.example.Application'
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootWarIntegrationTests-classesFromASecondarySourceSetCanBeIncludedInTheArchive.gradle

@@ -0,0 +1,15 @@
+plugins {
+	id 'war'
+	id 'org.springframework.boot' version '{version}'
+}
+
+sourceSets {
+	secondary
+	main {
+		runtimeClasspath += secondary.output
+	}
+}
+
+bootWar {
+	mainClass = 'com.example.Application'
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/run/BootRunIntegrationTests-classesFromASecondarySourceSetCanBeOnTheClasspath.gradle

@@ -0,0 +1,15 @@
+plugins {
+	id 'java'
+	id 'org.springframework.boot' version '{version}'
+}
+
+sourceSets {
+	secondary
+	main {
+		runtimeClasspath += secondary.output
+	}
+}
+
+springBoot {
+	mainClass = 'com.example.bootrun.main.CustomMainClass'
+}