Support @import on interfaces

Closes spring-projectsgh-34805

Signed-off-by: Daeho Kwon <[email protected]>

Author: kwondh5217

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java

@@ -98,6 +98,7 @@
  * @author Phillip Webb
  * @author Sam Brannen
  * @author Stephane Nicoll
+ * @author Daeho Kwon
  * @since 3.0
  * @see ConfigurationClassBeanDefinitionReader
  */
@@ -549,6 +550,9 @@ private Set<SourceClass> getImports(SourceClass sourceClass) throws IOException
 	 * <p>For example, it is common for a {@code @Configuration} class to declare direct
 	 * {@code @Import}s in addition to meta-imports originating from an {@code @Enable}
 	 * annotation.
+	 * <p>In addition, {@code @Import} annotations declared on interfaces implemented by
+	 * the configuration class are also considered. This allows imports to be triggered
+	 * indirectly via marker interfaces or shared base interfaces.
 	 * @param sourceClass the class to search
 	 * @param imports the imports collected so far
 	 * @param visited used to track visited classes to prevent infinite recursion
@@ -565,6 +569,10 @@ private void collectImports(SourceClass sourceClass, Set<SourceClass> imports, S
 				}
 			}
 			imports.addAll(sourceClass.getAnnotationAttributes(Import.class.getName(), "value"));
+
+			for (SourceClass ifc : sourceClass.getInterfaces()) {
+				collectImports(ifc, imports, visited);
+			}
 		}
 	}
 

spring-context/src/test/java/org/springframework/context/annotation/ImportSelectorTests.java

@@ -62,6 +62,7 @@
  *
  * @author Phillip Webb
  * @author Stephane Nicoll
+ * @author Daeho Kwon
  */
 @SuppressWarnings("resource")
 public class ImportSelectorTests {
@@ -152,7 +153,7 @@ void importSelectorsSeparateWithGroup() {
 		ordered.verify(beanFactory).registerBeanDefinition(eq("d"), any());
 		assertThat(TestImportGroup.instancesCount.get()).isEqualTo(1);
 		assertThat(TestImportGroup.imports.keySet().stream().map(AnnotationMetadata::getClassName))
-				.containsExactly(GroupedConfig2.class.getName(),GroupedConfig1.class.getName());
+				.containsExactly(GroupedConfig2.class.getName(), GroupedConfig1.class.getName());
 	}
 
 	@Test
@@ -168,11 +169,11 @@ void importSelectorsWithNestedGroup() {
 		assertThat(TestImportGroup.instancesCount.get()).isEqualTo(2);
 		assertThat(TestImportGroup.imports).hasSize(2);
 		assertThat(TestImportGroup.allImports())
-			.containsOnlyKeys(ParentConfiguration1.class.getName(), ChildConfiguration1.class.getName());
+				.containsOnlyKeys(ParentConfiguration1.class.getName(), ChildConfiguration1.class.getName());
 		assertThat(TestImportGroup.allImports().get(ParentConfiguration1.class.getName()))
-			.containsExactly(DeferredImportSelector1.class.getName(), ChildConfiguration1.class.getName());
+				.containsExactly(DeferredImportSelector1.class.getName(), ChildConfiguration1.class.getName());
 		assertThat(TestImportGroup.allImports().get(ChildConfiguration1.class.getName()))
-			.containsExactly(DeferredImportedSelector3.class.getName());
+				.containsExactly(DeferredImportedSelector3.class.getName());
 	}
 
 	@Test
@@ -187,11 +188,11 @@ void importSelectorsWithNestedGroupSameDeferredImport() {
 		assertThat(TestImportGroup.instancesCount.get()).isEqualTo(2);
 		assertThat(TestImportGroup.allImports()).hasSize(2);
 		assertThat(TestImportGroup.allImports())
-			.containsOnlyKeys(ParentConfiguration2.class.getName(), ChildConfiguration2.class.getName());
+				.containsOnlyKeys(ParentConfiguration2.class.getName(), ChildConfiguration2.class.getName());
 		assertThat(TestImportGroup.allImports().get(ParentConfiguration2.class.getName()))
-			.containsExactly(DeferredImportSelector2.class.getName(), ChildConfiguration2.class.getName());
+				.containsExactly(DeferredImportSelector2.class.getName(), ChildConfiguration2.class.getName());
 		assertThat(TestImportGroup.allImports().get(ChildConfiguration2.class.getName()))
-			.containsExactly(DeferredImportSelector2.class.getName());
+				.containsExactly(DeferredImportSelector2.class.getName());
 	}
 
 	@Test
@@ -203,6 +204,38 @@ void invokeAwareMethodsInImportGroup() {
 		assertThat(TestImportGroup.environment).isEqualTo(context.getEnvironment());
 	}
 
+	@Test
+	void importAnnotationOnImplementedInterfaceIsRespected() {
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
+		context.register(InterfaceBasedConfig.class);
+		context.refresh();
+
+		assertThat(context.getBean(ImportedConfig.class)).isNotNull();
+		assertThat(context.getBean(ImportedBean.class)).isNotNull();
+		assertThat(context.getBean(ImportedBean.class).name()).isEqualTo("imported");
+	}
+
+	@Import(ImportedConfig.class)
+	interface ConfigImportMarker {
+	}
+
+	@Configuration
+	static class InterfaceBasedConfig implements ConfigImportMarker {
+	}
+
+	static class ImportedBean {
+		String name() {
+			return "imported";
+		}
+	}
+
+	@Configuration
+	static class ImportedConfig {
+		@Bean
+		ImportedBean importedBean() {
+			return new ImportedBean();
+		}
+	}
 
 	@Configuration
 	@Import(SampleImportSelector.class)
@@ -247,7 +280,7 @@ public void setEnvironment(Environment environment) {
 
 		@Override
 		public String[] selectImports(AnnotationMetadata importingClassMetadata) {
-			return new String[] {};
+			return new String[]{};
 		}
 	}
 
@@ -271,7 +304,7 @@ public static class ImportSelector1 implements ImportSelector {
 		@Override
 		public String[] selectImports(AnnotationMetadata importingClassMetadata) {
 			ImportSelectorTests.importFrom.put(getClass(), importingClassMetadata.getClassName());
-			return new String[] { ImportedSelector1.class.getName() };
+			return new String[]{ImportedSelector1.class.getName()};
 		}
 	}
 
@@ -281,7 +314,7 @@ public static class ImportSelector2 implements ImportSelector {
 		@Override
 		public String[] selectImports(AnnotationMetadata importingClassMetadata) {
 			ImportSelectorTests.importFrom.put(getClass(), importingClassMetadata.getClassName());
-			return new String[] { ImportedSelector2.class.getName() };
+			return new String[]{ImportedSelector2.class.getName()};
 		}
 	}
 
@@ -294,7 +327,7 @@ public static class FilteredImportSelector implements ImportSelector {
 
 		@Override
 		public String[] selectImports(AnnotationMetadata importingClassMetadata) {
-			return new String[] { ImportedSelector1.class.getName(), ImportedSelector2.class.getName(), ImportedSelector3.class.getName() };
+			return new String[]{ImportedSelector1.class.getName(), ImportedSelector2.class.getName(), ImportedSelector3.class.getName()};
 		}
 
 		@Override
@@ -310,7 +343,7 @@ public static class DeferredImportSelector1 implements DeferredImportSelector, O
 		@Override
 		public String[] selectImports(AnnotationMetadata importingClassMetadata) {
 			ImportSelectorTests.importFrom.put(getClass(), importingClassMetadata.getClassName());
-			return new String[] { DeferredImportedSelector1.class.getName() };
+			return new String[]{DeferredImportedSelector1.class.getName()};
 		}
 
 		@Override
@@ -326,7 +359,7 @@ public static class DeferredImportSelector2 implements DeferredImportSelector {
 		@Override
 		public String[] selectImports(AnnotationMetadata importingClassMetadata) {
 			ImportSelectorTests.importFrom.put(getClass(), importingClassMetadata.getClassName());
-			return new String[] { DeferredImportedSelector2.class.getName() };
+			return new String[]{DeferredImportedSelector2.class.getName()};
 		}
 	}
 
@@ -399,7 +432,7 @@ public static class IndirectImportSelector implements ImportSelector {
 
 		@Override
 		public String[] selectImports(AnnotationMetadata importingClassMetadata) {
-			return new String[] {IndirectImport.class.getName()};
+			return new String[]{IndirectImport.class.getName()};
 		}
 
 		@Override
@@ -465,7 +498,7 @@ public static class ParentDeferredImportSelector1 implements DeferredImportSelec
 		@Override
 		public String[] selectImports(AnnotationMetadata importingClassMetadata) {
 			ImportSelectorTests.importFrom.put(getClass(), importingClassMetadata.getClassName());
-			return new String[] { DeferredImportSelector1.class.getName(), ChildConfiguration1.class.getName() };
+			return new String[]{DeferredImportSelector1.class.getName(), ChildConfiguration1.class.getName()};
 		}
 
 		@Override
@@ -485,7 +518,7 @@ public static class ParentDeferredImportSelector2 implements DeferredImportSelec
 		@Override
 		public String[] selectImports(AnnotationMetadata importingClassMetadata) {
 			ImportSelectorTests.importFrom.put(getClass(), importingClassMetadata.getClassName());
-			return new String[] { DeferredImportSelector2.class.getName(), ChildConfiguration2.class.getName() };
+			return new String[]{DeferredImportSelector2.class.getName(), ChildConfiguration2.class.getName()};
 		}
 
 		@Override
@@ -507,7 +540,7 @@ public static class ChildDeferredImportSelector1 implements DeferredImportSelect
 		@Override
 		public String[] selectImports(AnnotationMetadata importingClassMetadata) {
 			ImportSelectorTests.importFrom.put(getClass(), importingClassMetadata.getClassName());
-			return new String[] { DeferredImportedSelector3.class.getName() };
+			return new String[]{DeferredImportedSelector3.class.getName()};
 		}
 
 		@Override
@@ -528,7 +561,7 @@ public static class ChildDeferredImportSelector2 implements DeferredImportSelect
 		@Override
 		public String[] selectImports(AnnotationMetadata importingClassMetadata) {
 			ImportSelectorTests.importFrom.put(getClass(), importingClassMetadata.getClassName());
-			return new String[] { DeferredImportSelector2.class.getName() };
+			return new String[]{DeferredImportSelector2.class.getName()};
 		}
 
 		@Override