Refine ImportsContextCustomizer cache logic

Update `ImportsContextCustomizer` so that whenever possible a more
specific cache key is used.

Prior to this commit the customizer would generate a key based on *all*
annotations on the test class. This has repeatedly caused issues where
test classes that should have the same cache key did not due to
unrelated annotations.

A new `DeterminableImports` interface has been added that can be
implemented by `ImportSelector` and `ImportBeanDefinitionRegistrar`
implementations that are able to determine their imports early. The
existing `ImportAutoConfigurationImportSelector` and
`AutoConfigurationPackages` classes have been retrofitted with
this interface.

Fixes gh-7953

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/AutoConfigurationPackages.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@ package org.springframework.boot.autoconfigure;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Set;
@@ -31,6 +32,7 @@ import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.ConstructorArgumentValues;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.beans.factory.support.GenericBeanDefinition;
+import org.springframework.boot.context.annotation.DeterminableImports;
 import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
 import org.springframework.core.Ordered;
 import org.springframework.core.annotation.Order;
@@ -122,12 +124,52 @@ public abstract class AutoConfigurationPackages {
 	 * configuration.
 	 */
 	@Order(Ordered.HIGHEST_PRECEDENCE)
-	static class Registrar implements ImportBeanDefinitionRegistrar {
+	static class Registrar implements ImportBeanDefinitionRegistrar, DeterminableImports {
 
 		@Override
 		public void registerBeanDefinitions(AnnotationMetadata metadata,
 				BeanDefinitionRegistry registry) {
-			register(registry, ClassUtils.getPackageName(metadata.getClassName()));
+			register(registry, new PackageImport(metadata).getPackageName());
+		}
+
+		@Override
+		public Set<Object> determineImports(AnnotationMetadata metadata) {
+			return Collections.<Object>singleton(new PackageImport(metadata));
+		}
+
+	}
+
+	/**
+	 * Wrapper for a package import.
+	 */
+	private final static class PackageImport {
+
+		private final String packageName;
+
+		PackageImport(AnnotationMetadata metadata) {
+			this.packageName = ClassUtils.getPackageName(metadata.getClassName());
+		}
+
+		@Override
+		public int hashCode() {
+			return this.packageName.hashCode();
+		}
+
+		@Override
+		public boolean equals(Object obj) {
+			if (obj == null || getClass() != obj.getClass()) {
+				return false;
+			}
+			return this.packageName.equals(((PackageImport) obj).packageName);
+		}
+
+		public String getPackageName() {
+			return this.packageName;
+		}
+
+		@Override
+		public String toString() {
+			return "Package Import " + this.packageName;
 		}
 
 	}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/ImportAutoConfigurationImportSelector.java

@@ -27,6 +27,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
+import org.springframework.boot.context.annotation.DeterminableImports;
 import org.springframework.core.annotation.AnnotatedElementUtils;
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.annotation.AnnotationUtils;
@@ -44,7 +45,8 @@ import org.springframework.util.ObjectUtils;
  * @author Phillip Webb
  * @author Andy Wilkinson
  */
-class ImportAutoConfigurationImportSelector extends AutoConfigurationImportSelector {
+class ImportAutoConfigurationImportSelector extends AutoConfigurationImportSelector
+		implements DeterminableImports {
 
 	private static final Set<String> ANNOTATION_NAMES;
 
@@ -55,6 +57,14 @@ class ImportAutoConfigurationImportSelector extends AutoConfigurationImportSelec
 		ANNOTATION_NAMES = Collections.unmodifiableSet(names);
 	}
 
+	@Override
+	public Set<Object> determineImports(AnnotationMetadata metadata) {
+		Set<String> result = new LinkedHashSet<String>();
+		result.addAll(getCandidateConfigurations(metadata, null));
+		result.removeAll(getExclusions(metadata, null));
+		return Collections.<Object>unmodifiableSet(result);
+	}
+
 	@Override
 	protected AnnotationAttributes getAttributes(AnnotationMetadata metadata) {
 		return null;
@@ -85,6 +95,10 @@ class ImportAutoConfigurationImportSelector extends AutoConfigurationImportSelec
 		if (classes.length > 0) {
 			return Arrays.asList(classes);
 		}
+		return loadFactoryNames(source);
+	}
+
+	protected Collection<String> loadFactoryNames(Class<?> source) {
 		return SpringFactoriesLoader.loadFactoryNames(source,
 				getClass().getClassLoader());
 	}
@@ -117,7 +131,8 @@ class ImportAutoConfigurationImportSelector extends AutoConfigurationImportSelec
 		return exclusions;
 	}
 
-	private Map<Class<?>, List<Annotation>> getAnnotations(AnnotationMetadata metadata) {
+	protected final Map<Class<?>, List<Annotation>> getAnnotations(
+			AnnotationMetadata metadata) {
 		MultiValueMap<Class<?>, Annotation> annotations = new LinkedMultiValueMap<Class<?>, Annotation>();
 		Class<?> source = ClassUtils.resolveClassName(metadata.getClassName(), null);
 		collectAnnotations(source, annotations, new HashSet<Class<?>>());

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/ImportAutoConfigurationImportSelectorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,9 @@ package org.springframework.boot.autoconfigure;
 import java.io.IOException;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Set;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -46,7 +49,7 @@ import static org.mockito.Mockito.verifyZeroInteractions;
  */
 public class ImportAutoConfigurationImportSelectorTests {
 
-	private final ImportAutoConfigurationImportSelector importSelector = new ImportAutoConfigurationImportSelector();
+	private final ImportAutoConfigurationImportSelector importSelector = new TestImportAutoConfigurationImportSelector();
 
 	private final ConfigurableListableBeanFactory beanFactory = new DefaultListableBeanFactory();
 
@@ -63,36 +66,32 @@ public class ImportAutoConfigurationImportSelectorTests {
 
 	@Test
 	public void importsAreSelected() throws Exception {
-		AnnotationMetadata annotationMetadata = new SimpleMetadataReaderFactory()
-				.getMetadataReader(ImportFreeMarker.class.getName())
-				.getAnnotationMetadata();
+		AnnotationMetadata annotationMetadata = getAnnotationMetadata(
+				ImportFreeMarker.class);
 		String[] imports = this.importSelector.selectImports(annotationMetadata);
 		assertThat(imports).containsExactly(FreeMarkerAutoConfiguration.class.getName());
 	}
 
 	@Test
 	public void importsAreSelectedUsingClassesAttribute() throws Exception {
-		AnnotationMetadata annotationMetadata = new SimpleMetadataReaderFactory()
-				.getMetadataReader(ImportFreeMarkerUsingClassesAttribute.class.getName())
-				.getAnnotationMetadata();
+		AnnotationMetadata annotationMetadata = getAnnotationMetadata(
+				ImportFreeMarkerUsingClassesAttribute.class);
 		String[] imports = this.importSelector.selectImports(annotationMetadata);
 		assertThat(imports).containsExactly(FreeMarkerAutoConfiguration.class.getName());
 	}
 
 	@Test
 	public void propertyExclusionsAreNotApplied() throws Exception {
-		AnnotationMetadata annotationMetadata = new SimpleMetadataReaderFactory()
-				.getMetadataReader(ImportFreeMarker.class.getName())
-				.getAnnotationMetadata();
+		AnnotationMetadata annotationMetadata = getAnnotationMetadata(
+				ImportFreeMarker.class);
 		this.importSelector.selectImports(annotationMetadata);
 		verifyZeroInteractions(this.environment);
 	}
 
 	@Test
 	public void multipleImportsAreFound() throws Exception {
-		AnnotationMetadata annotationMetadata = new SimpleMetadataReaderFactory()
-				.getMetadataReader(MultipleImports.class.getName())
-				.getAnnotationMetadata();
+		AnnotationMetadata annotationMetadata = getAnnotationMetadata(
+				MultipleImports.class);
 		String[] imports = this.importSelector.selectImports(annotationMetadata);
 		assertThat(imports).containsOnly(FreeMarkerAutoConfiguration.class.getName(),
 				ThymeleafAutoConfiguration.class.getName());
@@ -100,41 +99,94 @@ public class ImportAutoConfigurationImportSelectorTests {
 
 	@Test
 	public void selfAnnotatingAnnotationDoesNotCauseStackOverflow() throws IOException {
-		AnnotationMetadata annotationMetadata = new SimpleMetadataReaderFactory()
-				.getMetadataReader(ImportWithSelfAnnotatingAnnotation.class.getName())
-				.getAnnotationMetadata();
+		AnnotationMetadata annotationMetadata = getAnnotationMetadata(
+				ImportWithSelfAnnotatingAnnotation.class);
 		String[] imports = this.importSelector.selectImports(annotationMetadata);
 		assertThat(imports).containsOnly(ThymeleafAutoConfiguration.class.getName());
 	}
 
 	@Test
 	public void exclusionsAreApplied() throws Exception {
-		AnnotationMetadata annotationMetadata = new SimpleMetadataReaderFactory()
-				.getMetadataReader(MultipleImportsWithExclusion.class.getName())
-				.getAnnotationMetadata();
+		AnnotationMetadata annotationMetadata = getAnnotationMetadata(
+				MultipleImportsWithExclusion.class);
 		String[] imports = this.importSelector.selectImports(annotationMetadata);
 		assertThat(imports).containsOnly(FreeMarkerAutoConfiguration.class.getName());
 	}
 
 	@Test
 	public void exclusionsWithoutImport() throws Exception {
-		AnnotationMetadata annotationMetadata = new SimpleMetadataReaderFactory()
-				.getMetadataReader(ExclusionWithoutImport.class.getName())
-				.getAnnotationMetadata();
+		AnnotationMetadata annotationMetadata = getAnnotationMetadata(
+				ExclusionWithoutImport.class);
 		String[] imports = this.importSelector.selectImports(annotationMetadata);
 		assertThat(imports).containsOnly(FreeMarkerAutoConfiguration.class.getName());
 	}
 
 	@Test
 	public void exclusionsAliasesAreApplied() throws Exception {
-		AnnotationMetadata annotationMetadata = new SimpleMetadataReaderFactory()
-				.getMetadataReader(
-						ImportWithSelfAnnotatingAnnotationExclude.class.getName())
-				.getAnnotationMetadata();
+		AnnotationMetadata annotationMetadata = getAnnotationMetadata(
+				ImportWithSelfAnnotatingAnnotationExclude.class);
+
 		String[] imports = this.importSelector.selectImports(annotationMetadata);
 		assertThat(imports).isEmpty();
 	}
 
+	@Test
+	public void determineImportsWhenUsingMetaWithoutClassesShouldBeEqual()
+			throws Exception {
+		Set<Object> set1 = this.importSelector.determineImports(
+				getAnnotationMetadata(ImportMetaAutoConfigurationWithUnrelatedOne.class));
+		Set<Object> set2 = this.importSelector.determineImports(
+				getAnnotationMetadata(ImportMetaAutoConfigurationWithUnrelatedTwo.class));
+		assertThat(set1).isEqualTo(set2);
+		assertThat(set1.hashCode()).isEqualTo(set2.hashCode());
+	}
+
+	@Test
+	public void determineImportsWhenUsingNonMetaWithoutClassesShouldBeSame()
+			throws Exception {
+		Set<Object> set1 = this.importSelector.determineImports(
+				getAnnotationMetadata(ImportAutoConfigurationWithUnrelatedOne.class));
+		Set<Object> set2 = this.importSelector.determineImports(
+				getAnnotationMetadata(ImportAutoConfigurationWithUnrelatedTwo.class));
+		assertThat(set1).isEqualTo(set2);
+	}
+
+	@Test
+	public void determineImportsWhenUsingNonMetaWithClassesShouldBeSame()
+			throws Exception {
+		Set<Object> set1 = this.importSelector.determineImports(
+				getAnnotationMetadata(ImportAutoConfigurationWithItemsOne.class));
+		Set<Object> set2 = this.importSelector.determineImports(
+				getAnnotationMetadata(ImportAutoConfigurationWithItemsOne.class));
+		assertThat(set1).isEqualTo(set2);
+	}
+
+	@Test
+	public void determineImportsWhenUsingMetaExcludeWithoutClassesShouldBeEqual()
+			throws Exception {
+		Set<Object> set1 = this.importSelector.determineImports(getAnnotationMetadata(
+				ImportMetaAutoConfigurationExcludeWithUnrelatedOne.class));
+		Set<Object> set2 = this.importSelector.determineImports(getAnnotationMetadata(
+				ImportMetaAutoConfigurationExcludeWithUnrelatedTwo.class));
+		assertThat(set1).isEqualTo(set2);
+		assertThat(set1.hashCode()).isEqualTo(set2.hashCode());
+	}
+
+	@Test
+	public void determineImportsWhenUsingMetaDifferentExcludeWithoutClassesShouldBeDifferent()
+			throws Exception {
+		Set<Object> set1 = this.importSelector.determineImports(getAnnotationMetadata(
+				ImportMetaAutoConfigurationExcludeWithUnrelatedOne.class));
+		Set<Object> set2 = this.importSelector.determineImports(
+				getAnnotationMetadata(ImportMetaAutoConfigurationWithUnrelatedTwo.class));
+		assertThat(set1).isNotEqualTo(set2);
+	}
+
+	private AnnotationMetadata getAnnotationMetadata(Class<?> source) throws IOException {
+		return new SimpleMetadataReaderFactory().getMetadataReader(source.getName())
+				.getAnnotationMetadata();
+	}
+
 	@ImportAutoConfiguration(FreeMarkerAutoConfiguration.class)
 	static class ImportFreeMarker {
 
@@ -186,6 +238,73 @@ public class ImportAutoConfigurationImportSelectorTests {
 
 	}
 
+	@MetaImportAutoConfiguration
+	@UnrelatedOne
+	static class ImportMetaAutoConfigurationWithUnrelatedOne {
+
+	}
+
+	@MetaImportAutoConfiguration
+	@UnrelatedTwo
+	static class ImportMetaAutoConfigurationWithUnrelatedTwo {
+
+	}
+
+	@ImportAutoConfiguration
+	@UnrelatedOne
+	static class ImportAutoConfigurationWithUnrelatedOne {
+
+	}
+
+	@ImportAutoConfiguration
+	@UnrelatedTwo
+	static class ImportAutoConfigurationWithUnrelatedTwo {
+
+	}
+
+	@ImportAutoConfiguration(classes = ThymeleafAutoConfiguration.class)
+	@UnrelatedOne
+	static class ImportAutoConfigurationWithItemsOne {
+
+	}
+
+	@ImportAutoConfiguration(classes = ThymeleafAutoConfiguration.class)
+	@UnrelatedOne
+	static class ImportAutoConfigurationWithItemsTwo {
+
+	}
+
+	@MetaImportAutoConfiguration(exclude = ThymeleafAutoConfiguration.class)
+	@UnrelatedOne
+	static class ImportMetaAutoConfigurationExcludeWithUnrelatedOne {
+
+	}
+
+	@MetaImportAutoConfiguration(exclude = ThymeleafAutoConfiguration.class)
+	@UnrelatedTwo
+	static class ImportMetaAutoConfigurationExcludeWithUnrelatedTwo {
+
+	}
+
+	@ImportAutoConfiguration
+	@Retention(RetentionPolicy.RUNTIME)
+	static @interface MetaImportAutoConfiguration {
+
+		@AliasFor(annotation = ImportAutoConfiguration.class, attribute = "exclude")
+		Class<?>[] exclude() default {};
+
+	}
+
+	@Retention(RetentionPolicy.RUNTIME)
+	static @interface UnrelatedOne {
+
+	}
+
+	@Retention(RetentionPolicy.RUNTIME)
+	static @interface UnrelatedTwo {
+
+	}
+
 	@Retention(RetentionPolicy.RUNTIME)
 	@ImportAutoConfiguration(ThymeleafAutoConfiguration.class)
 	@SelfAnnotating
@@ -196,4 +315,18 @@ public class ImportAutoConfigurationImportSelectorTests {
 
 	}
 
+	private static class TestImportAutoConfigurationImportSelector
+			extends ImportAutoConfigurationImportSelector {
+
+		@Override
+		protected Collection<String> loadFactoryNames(Class<?> source) {
+			if (source == MetaImportAutoConfiguration.class) {
+				return Arrays.asList(ThymeleafAutoConfiguration.class.getName(),
+						FreeMarkerAutoConfiguration.class.getName());
+			}
+			return super.loadFactoryNames(source);
+		}
+
+	}
+
 }

spring-boot-test-autoconfigure/src/test/java/org/springframework/boot/test/autoconfigure/cache/ImportsContextCustomizerFactoryWithAutoConfigurationTests.java

@@ -0,0 +1,158 @@
+/*
+ * Copyright 2012-2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.test.autoconfigure.cache;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+import org.junit.Test;
+import org.junit.runner.notification.RunNotifier;
+import org.junit.runners.model.InitializationError;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.ImportAutoConfiguration;
+import org.springframework.boot.autoconfigure.domain.EntityScan;
+import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
+import org.springframework.boot.test.autoconfigure.orm.jpa.ExampleEntity;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@code ImportsContextCustomizerFactory} when used with
+ * {@link ImportAutoConfiguration}.
+ *
+ * @author Phillip Webb
+ * @author Andy Wilkinson
+ */
+public class ImportsContextCustomizerFactoryWithAutoConfigurationTests {
+
+	static ApplicationContext contextFromTest;
+
+	@Test
+	public void testClassesThatHaveSameAnnotationsShareAContext()
+			throws InitializationError {
+		RunNotifier notifier = new RunNotifier();
+		new SpringJUnit4ClassRunner(DataJpaTest1.class).run(notifier);
+		ApplicationContext test1Context = contextFromTest;
+		new SpringJUnit4ClassRunner(DataJpaTest3.class).run(notifier);
+		ApplicationContext test2Context = contextFromTest;
+		assertThat(test1Context).isSameAs(test2Context);
+	}
+
+	@Test
+	public void testClassesThatOnlyHaveDifferingUnrelatedAnnotationsShareAContext()
+			throws InitializationError {
+		RunNotifier notifier = new RunNotifier();
+		new SpringJUnit4ClassRunner(DataJpaTest1.class).run(notifier);
+		ApplicationContext test1Context = contextFromTest;
+		new SpringJUnit4ClassRunner(DataJpaTest2.class).run(notifier);
+		ApplicationContext test2Context = contextFromTest;
+		assertThat(test1Context).isSameAs(test2Context);
+	}
+
+	@Test
+	public void testClassesThatOnlyHaveDifferingPropertyMappedAnnotationAttributesDoNotShareAContext()
+			throws InitializationError {
+		RunNotifier notifier = new RunNotifier();
+		new SpringJUnit4ClassRunner(DataJpaTest1.class).run(notifier);
+		ApplicationContext test1Context = contextFromTest;
+		new SpringJUnit4ClassRunner(DataJpaTest4.class).run(notifier);
+		ApplicationContext test2Context = contextFromTest;
+		assertThat(test1Context).isNotSameAs(test2Context);
+	}
+
+	@DataJpaTest
+	@ContextConfiguration(classes = EmptyConfig.class)
+	@Unrelated1
+	public static class DataJpaTest1 {
+
+		@Autowired
+		private ApplicationContext context;
+
+		@Test
+		public void test() {
+			contextFromTest = this.context;
+		}
+
+	}
+
+	@ContextConfiguration(classes = EmptyConfig.class)
+	@DataJpaTest
+	@Unrelated2
+	public static class DataJpaTest2 {
+
+		@Autowired
+		private ApplicationContext context;
+
+		@Test
+		public void test() {
+			contextFromTest = this.context;
+		}
+
+	}
+
+	@ContextConfiguration(classes = EmptyConfig.class)
+	@DataJpaTest
+	@Unrelated1
+	public static class DataJpaTest3 {
+
+		@Autowired
+		private ApplicationContext context;
+
+		@Test
+		public void test() {
+			contextFromTest = this.context;
+		}
+
+	}
+
+	@ContextConfiguration(classes = EmptyConfig.class)
+	@DataJpaTest(showSql = false)
+	@Unrelated1
+	public static class DataJpaTest4 {
+
+		@Autowired
+		private ApplicationContext context;
+
+		@Test
+		public void test() {
+			contextFromTest = this.context;
+		}
+
+	}
+
+	@Retention(RetentionPolicy.RUNTIME)
+	static @interface Unrelated1 {
+
+	}
+
+	@Retention(RetentionPolicy.RUNTIME)
+	static @interface Unrelated2 {
+
+	}
+
+	@Configuration
+	@EntityScan(basePackageClasses = ExampleEntity.class)
+	static class EmptyConfig {
+
+	}
+
+}

spring-boot-test/src/main/java/org/springframework/boot/test/context/ImportsContextCustomizer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,8 +18,10 @@ package org.springframework.boot.test.context;
 
 import java.lang.annotation.Annotation;
 import java.lang.reflect.AnnotatedElement;
+import java.lang.reflect.Constructor;
 import java.util.Collections;
 import java.util.HashSet;
+import java.util.LinkedHashSet;
 import java.util.Set;
 
 import org.springframework.beans.BeansException;
@@ -30,19 +32,24 @@ import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
+import org.springframework.boot.context.annotation.DeterminableImports;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.AnnotatedBeanDefinitionReader;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
+import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
 import org.springframework.context.annotation.ImportSelector;
 import org.springframework.context.support.AbstractApplicationContext;
 import org.springframework.core.Ordered;
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.core.annotation.Order;
+import org.springframework.core.style.ToStringCreator;
 import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.core.type.StandardAnnotationMetadata;
 import org.springframework.test.context.ContextCustomizer;
 import org.springframework.test.context.MergedContextConfiguration;
+import org.springframework.util.ReflectionUtils;
 
 /**
  * {@link ContextCustomizer} to allow {@code @Import} annotations to be used directly on
@@ -127,6 +134,11 @@ class ImportsContextCustomizer implements ContextCustomizer {
 		return this.key.equals(other.key);
 	}
 
+	@Override
+	public String toString() {
+		return new ToStringCreator(this).append("key", this.key).toString();
+	}
+
 	/**
 	 * {@link Configuration} registered to trigger the {@link ImportsSelector}.
 	 */
@@ -214,6 +226,8 @@ class ImportsContextCustomizer implements ContextCustomizer {
 	 */
 	static class ContextCustomizerKey {
 
+		private static final Class<?>[] NO_IMPORTS = {};
+
 		private static final Set<AnnotationFilter> ANNOTATION_FILTERS;
 
 		static {
@@ -224,13 +238,15 @@ class ImportsContextCustomizer implements ContextCustomizer {
 			ANNOTATION_FILTERS = Collections.unmodifiableSet(filters);
 		}
 
-		private final Set<Annotation> annotations;
+		private final Set<Object> key;
 
 		ContextCustomizerKey(Class<?> testClass) {
 			Set<Annotation> annotations = new HashSet<Annotation>();
 			Set<Class<?>> seen = new HashSet<Class<?>>();
 			collectClassAnnotations(testClass, annotations, seen);
-			this.annotations = Collections.unmodifiableSet(annotations);
+			Set<Object> determinedImports = determineImports(annotations, testClass);
+			this.key = Collections.<Object>unmodifiableSet(
+					determinedImports != null ? determinedImports : annotations);
 		}
 
 		private void collectClassAnnotations(Class<?> classType,
@@ -266,17 +282,78 @@ class ImportsContextCustomizer implements ContextCustomizer {
 			return false;
 		}
 
+		private Set<Object> determineImports(Set<Annotation> annotations,
+				Class<?> testClass) {
+			Set<Object> determinedImports = new LinkedHashSet<Object>();
+			AnnotationMetadata testClassMetadata = new StandardAnnotationMetadata(
+					testClass);
+			for (Annotation annotation : annotations) {
+				for (Class<?> source : getImports(annotation)) {
+					Set<Object> determinedSourceImports = determineImports(source,
+							testClassMetadata);
+					if (determinedSourceImports == null) {
+						return null;
+					}
+					determinedImports.addAll(determinedSourceImports);
+				}
+			}
+			return determinedImports;
+		}
+
+		private Class<?>[] getImports(Annotation annotation) {
+			if (annotation instanceof Import) {
+				return ((Import) annotation).value();
+			}
+			return NO_IMPORTS;
+		}
+
+		private Set<Object> determineImports(Class<?> source,
+				AnnotationMetadata metadata) {
+			if (DeterminableImports.class.isAssignableFrom(source)) {
+				// We can determine the imports
+				return ((DeterminableImports) instantiate(source))
+						.determineImports(metadata);
+			}
+			if (ImportSelector.class.isAssignableFrom(source)
+					|| ImportBeanDefinitionRegistrar.class.isAssignableFrom(source)) {
+				// Standard ImportSelector and ImportBeanDefinitionRegistrar could
+				// use anything to determine the imports so we can't be sure
+				return null;
+			}
+			// The source itself is the import
+			return Collections.<Object>singleton(source.getName());
+		}
+
+		@SuppressWarnings("unchecked")
+		private <T> T instantiate(Class<T> source) {
+			try {
+				Constructor<?> constructor = source.getDeclaredConstructor();
+				ReflectionUtils.makeAccessible(constructor);
+				return (T) constructor.newInstance();
+			}
+			catch (Throwable ex) {
+				throw new IllegalStateException(
+						"Unable to instantiate DeterminableImportSelector "
+								+ source.getName(),
+						ex);
+			}
+		}
+
 		@Override
 		public int hashCode() {
-			return this.annotations.hashCode();
+			return this.key.hashCode();
 		}
 
 		@Override
 		public boolean equals(Object obj) {
 			return (obj != null && getClass().equals(obj.getClass())
-					&& this.annotations.equals(((ContextCustomizerKey) obj).annotations));
+					&& this.key.equals(((ContextCustomizerKey) obj).key));
 		}
 
+		@Override
+		public String toString() {
+			return this.key.toString();
+		}
 	}
 
 	/**

spring-boot-test/src/test/java/org/springframework/boot/test/context/ImportsContextCustomizerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,21 @@
 
 package org.springframework.boot.test.context;
 
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.util.Collections;
+import java.util.Set;
+
 import kotlin.Metadata;
 import org.junit.Test;
 import org.spockframework.runtime.model.SpecMetadata;
 
+import org.springframework.boot.context.annotation.DeterminableImports;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+import org.springframework.context.annotation.ImportSelector;
+import org.springframework.core.type.AnnotationMetadata;
+
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**
@@ -29,6 +40,26 @@ import static org.assertj.core.api.Assertions.assertThat;
  */
 public class ImportsContextCustomizerTests {
 
+	@Test
+	public void importSelectorsCouldUseAnyAnnotations() throws Exception {
+		assertThat(new ImportsContextCustomizer(FirstImportSelectorAnnotatedClass.class))
+				.isNotEqualTo(new ImportsContextCustomizer(
+						SecondImportSelectorAnnotatedClass.class));
+	}
+
+	@Test
+	public void determinableImportSelector() throws Exception {
+		assertThat(new ImportsContextCustomizer(
+				FirstDeterminableImportSelectorAnnotatedClass.class))
+						.isEqualTo(new ImportsContextCustomizer(
+								SecondDeterminableImportSelectorAnnotatedClass.class));
+	}
+
+	@Test
+	public void importAutoConfigurationCanIgnoreAdditionalAnnotations() throws Exception {
+
+	}
+
 	@Test
 	public void customizersForTestClassesWithDifferentKotlinMetadataAreEqual() {
 		assertThat(new ImportsContextCustomizer(FirstKotlinAnnotatedTestClass.class))
@@ -43,6 +74,30 @@ public class ImportsContextCustomizerTests {
 						SecondSpockAnnotatedTestClass.class));
 	}
 
+	@Import(TestImportSelector.class)
+	@Indicator1
+	static class FirstImportSelectorAnnotatedClass {
+
+	}
+
+	@Import(TestImportSelector.class)
+	@Indicator2
+	static class SecondImportSelectorAnnotatedClass {
+
+	}
+
+	@Import(TestDeterminableImportSelector.class)
+	@Indicator1
+	static class FirstDeterminableImportSelectorAnnotatedClass {
+
+	}
+
+	@Import(TestDeterminableImportSelector.class)
+	@Indicator2
+	static class SecondDeterminableImportSelectorAnnotatedClass {
+
+	}
+
 	@Metadata(d2 = "foo")
 	static class FirstKotlinAnnotatedTestClass {
 
@@ -63,4 +118,43 @@ public class ImportsContextCustomizerTests {
 
 	}
 
+	@Retention(RetentionPolicy.RUNTIME)
+	@interface Indicator1 {
+
+	}
+
+	@Retention(RetentionPolicy.RUNTIME)
+	@interface Indicator2 {
+
+	}
+
+	static class TestImportSelector implements ImportSelector {
+
+		@Override
+		public String[] selectImports(AnnotationMetadata arg0) {
+			return new String[] {};
+		}
+
+	}
+
+	static class TestDeterminableImportSelector
+			implements ImportSelector, DeterminableImports {
+
+		@Override
+		public String[] selectImports(AnnotationMetadata arg0) {
+			return new String[] { TestConfig.class.getName() };
+		}
+
+		@Override
+		public Set<Object> determineImports(AnnotationMetadata metadata) {
+			return Collections.<Object>singleton(TestConfig.class.getName());
+		}
+
+	}
+
+	@Configuration
+	static class TestConfig {
+
+	}
+
 }

spring-boot/src/main/java/org/springframework/boot/context/annotation/DeterminableImports.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2012-2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.context.annotation;
+
+import java.util.Set;
+
+import org.springframework.beans.factory.Aware;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
+import org.springframework.context.annotation.ImportSelector;
+import org.springframework.core.type.AnnotationMetadata;
+
+/**
+ * Interface that can be implemented by {@link ImportSelector} and
+ * {@link ImportBeanDefinitionRegistrar} implementations when they can determine imports
+ * early. The {@link ImportSelector} and {@link ImportBeanDefinitionRegistrar} interfaces
+ * are quite flexible which can make it hard to tell exactly what bean definitions they
+ * will add. This interface should be used when an implementation consistently result in
+ * the same imports, given the same source.
+ * <p>
+ * Using {@link DeterminableImports} is particularly useful when working with Spring's
+ * testing support. It allows for better generation of {@link ApplicationContext} cache
+ * keys.
+ *
+ * @author Phillip Webb
+ * @author Andy Wilkinson
+ * @since 1.5.0
+ */
+public interface DeterminableImports {
+
+	/**
+	 * Return a set of objects that represent the imports. Objects within the returned
+	 * {@code Set} must implement a valid {@link Object#hashCode() hashCode} and
+	 * {@link Object#equals(Object) equals}.
+	 * <p>
+	 * Imports from multiple {@link DeterminableImports} instances may be combined by the
+	 * caller to create a complete set.
+	 * <p>
+	 * Unlike {@link ImportSelector} and {@link ImportBeanDefinitionRegistrar} any
+	 * {@link Aware} callbacks will not be invoked before this method is called.
+	 * @param metadata the source meta-data
+	 * @return a key representing the annotations that actually drive the import
+	 */
+	Set<Object> determineImports(AnnotationMetadata metadata);
+
+}

spring-boot/src/main/java/org/springframework/boot/context/annotation/package-info.java

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2012-2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Classes related to Spring's {@link org.springframework.context.ApplicationContext}
+ * annotations.
+ */
+package org.springframework.boot.context.annotation;