Decorate all Assert implementations with @CheckReturnValue

build-plugin/spring-boot-maven-plugin/src/intTest/java/org/springframework/boot/maven/AbstractArchiveIntegrationTests.java

@@ -37,6 +37,8 @@
 import org.assertj.core.api.AssertProvider;
 import org.assertj.core.api.ListAssert;
 
+import org.springframework.lang.CheckReturnValue;
+
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.contentOf;
 
@@ -176,6 +178,7 @@ JarAssert doesNotHaveEntryWithNameStartingWith(String prefix) {
 			return this;
 		}
 
+		@CheckReturnValue
 		ListAssert<String> entryNamesInPath(String path) {
 			List<String> matches = new ArrayList<>();
 			withJarFile((jarFile) -> withEntries(jarFile,

config/checkstyle/import-control.xml

@@ -3,6 +3,7 @@
 <import-control pkg="org.springframework.boot">
 	<allow pkg="io.micrometer.observation" />
 	<disallow pkg="io.micrometer" />
+	<allow class="org.springframework.lang.CheckReturnValue" />
 	<allow class="org.springframework.lang.Contract" />
 	<disallow pkg="org.springframework.lang" />
 	<allow pkg=".*" regex="true" />

core/spring-boot-test/src/main/java/org/springframework/boot/test/context/assertj/ApplicationContextAssert.java

@@ -26,7 +26,6 @@
 import org.assertj.core.api.AbstractObjectArrayAssert;
 import org.assertj.core.api.AbstractObjectAssert;
 import org.assertj.core.api.AbstractThrowableAssert;
-import org.assertj.core.api.Assertions;
 import org.assertj.core.api.MapAssert;
 import org.assertj.core.error.BasicErrorMessageFactory;
 import org.jspecify.annotations.Nullable;
@@ -37,6 +36,7 @@
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.lang.CheckReturnValue;
 import org.springframework.util.Assert;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -224,13 +224,14 @@ public ApplicationContextAssert<C> doesNotHaveBean(String name) {
 	 * @return array assertions for the bean names
 	 * @throws AssertionError if the application context did not start
 	 */
+	@CheckReturnValue
 	public <T> AbstractObjectArrayAssert<?, String> getBeanNames(Class<T> type) {
 		if (this.startupFailure != null) {
 			throwAssertionError(contextFailedToStartWhenExpecting(this.startupFailure,
 					"to get beans names with type:%n <%s>", type));
 		}
-		return Assertions.assertThat(getApplicationContext().getBeanNamesForType(type))
-			.as("Bean names of type <%s> from <%s>", type, getApplicationContext());
+		return assertThat(getApplicationContext().getBeanNamesForType(type)).as("Bean names of type <%s> from <%s>",
+				type, getApplicationContext());
 	}
 
 	/**
@@ -249,6 +250,7 @@ public <T> AbstractObjectArrayAssert<?, String> getBeanNames(Class<T> type) {
 	 * @throws AssertionError if the application context contains multiple beans of the
 	 * given type
 	 */
+	@CheckReturnValue
 	public <T> AbstractObjectAssert<?, T> getBean(Class<T> type) {
 		return getBean(type, Scope.INCLUDE_ANCESTORS);
 	}
@@ -270,6 +272,7 @@ public <T> AbstractObjectAssert<?, T> getBean(Class<T> type) {
 	 * @throws AssertionError if the application context contains multiple beans of the
 	 * given type
 	 */
+	@CheckReturnValue
 	public <T> AbstractObjectAssert<?, T> getBean(Class<T> type, Scope scope) {
 		Assert.notNull(scope, "'scope' must not be null");
 		if (this.startupFailure != null) {
@@ -284,7 +287,7 @@ public <T> AbstractObjectAssert<?, T> getBean(Class<T> type, Scope scope) {
 							getApplicationContext(), type, names));
 		}
 		T bean = (name != null) ? getApplicationContext().getBean(name, type) : null;
-		return Assertions.assertThat(bean).as("Bean of type <%s> from <%s>", type, getApplicationContext());
+		return assertThat(bean).as("Bean of type <%s> from <%s>", type, getApplicationContext());
 	}
 
 	private @Nullable String getPrimary(String[] names, Scope scope) {
@@ -330,13 +333,14 @@ private boolean isPrimary(String name, Scope scope) {
 	 * is found
 	 * @throws AssertionError if the application context did not start
 	 */
+	@CheckReturnValue
 	public AbstractObjectAssert<?, Object> getBean(String name) {
 		if (this.startupFailure != null) {
 			throwAssertionError(
 					contextFailedToStartWhenExpecting(this.startupFailure, "to contain a bean of name:%n <%s>", name));
 		}
 		Object bean = findBean(name);
-		return Assertions.assertThat(bean).as("Bean of name <%s> from <%s>", name, getApplicationContext());
+		return assertThat(bean).as("Bean of name <%s> from <%s>", name, getApplicationContext());
 	}
 
 	/**
@@ -357,6 +361,7 @@ public AbstractObjectAssert<?, Object> getBean(String name) {
 	 * name but a different type
 	 */
 	@SuppressWarnings("unchecked")
+	@CheckReturnValue
 	public <T> AbstractObjectAssert<?, T> getBean(String name, Class<T> type) {
 		if (this.startupFailure != null) {
 			throwAssertionError(contextFailedToStartWhenExpecting(this.startupFailure,
@@ -368,8 +373,8 @@ public <T> AbstractObjectAssert<?, T> getBean(String name, Class<T> type) {
 					"%nExpecting:%n <%s>%nto contain a bean of name:%n <%s> (%s)%nbut found:%n <%s> of type <%s>",
 					getApplicationContext(), name, type, bean, bean.getClass()));
 		}
-		return Assertions.assertThat((T) bean)
-			.as("Bean of name <%s> and type <%s> from <%s>", name, type, getApplicationContext());
+		return assertThat((T) bean).as("Bean of name <%s> and type <%s> from <%s>", name, type,
+				getApplicationContext());
 	}
 
 	private @Nullable Object findBean(String name) {
@@ -395,6 +400,7 @@ public <T> AbstractObjectAssert<?, T> getBean(String name, Class<T> type) {
 	 * no beans are found
 	 * @throws AssertionError if the application context did not start
 	 */
+	@CheckReturnValue
 	public <T> MapAssert<String, T> getBeans(Class<T> type) {
 		return getBeans(type, Scope.INCLUDE_ANCESTORS);
 	}
@@ -414,14 +420,15 @@ public <T> MapAssert<String, T> getBeans(Class<T> type) {
 	 * no beans are found
 	 * @throws AssertionError if the application context did not start
 	 */
+	@CheckReturnValue
 	public <T> MapAssert<String, T> getBeans(Class<T> type, Scope scope) {
 		Assert.notNull(scope, "'scope' must not be null");
 		if (this.startupFailure != null) {
 			throwAssertionError(
 					contextFailedToStartWhenExpecting(this.startupFailure, "to get beans of type:%n <%s>", type));
 		}
-		return Assertions.assertThat(scope.getBeansOfType(getApplicationContext(), type))
-			.as("Beans of type <%s> from <%s>", type, getApplicationContext());
+		return assertThat(scope.getBeansOfType(getApplicationContext(), type)).as("Beans of type <%s> from <%s>", type,
+				getApplicationContext());
 	}
 
 	/**
@@ -434,6 +441,7 @@ public <T> MapAssert<String, T> getBeans(Class<T> type, Scope scope) {
 	 * @return assertions on the cause of the failure
 	 * @throws AssertionError if the application context started without a failure
 	 */
+	@CheckReturnValue
 	public AbstractThrowableAssert<?, ? extends Throwable> getFailure() {
 		hasFailed();
 		return assertThat(this.startupFailure);

core/spring-boot-test/src/main/java/org/springframework/boot/test/json/JsonContentAssert.java

@@ -40,6 +40,7 @@
 import org.skyscreamer.jsonassert.comparator.JSONComparator;
 
 import org.springframework.core.io.Resource;
+import org.springframework.lang.CheckReturnValue;
 import org.springframework.util.ObjectUtils;
 import org.springframework.util.StringUtils;
 
@@ -916,6 +917,7 @@ public JsonContentAssert doesNotHaveEmptyJsonPathValue(CharSequence expression,
 	 * @return a new assertion object whose object under test is the extracted item
 	 * @throws AssertionError if the path is not valid
 	 */
+	@CheckReturnValue
 	public AbstractObjectAssert<?, Object> extractingJsonPathValue(CharSequence expression, Object... args) {
 		return Assertions.assertThat(new JsonPathValue(expression, args).getValue(false));
 	}
@@ -928,6 +930,7 @@ public AbstractObjectAssert<?, Object> extractingJsonPathValue(CharSequence expr
 	 * @return a new assertion object whose object under test is the extracted item
 	 * @throws AssertionError if the path is not valid or does not result in a string
 	 */
+	@CheckReturnValue
 	public AbstractCharSequenceAssert<?, String> extractingJsonPathStringValue(CharSequence expression,
 			Object... args) {
 		return Assertions.assertThat(extractingJsonPathValue(expression, args, String.class, "a string"));
@@ -941,6 +944,7 @@ public AbstractCharSequenceAssert<?, String> extractingJsonPathStringValue(CharS
 	 * @return a new assertion object whose object under test is the extracted item
 	 * @throws AssertionError if the path is not valid or does not result in a number
 	 */
+	@CheckReturnValue
 	public AbstractObjectAssert<?, Number> extractingJsonPathNumberValue(CharSequence expression, Object... args) {
 		return Assertions.assertThat(extractingJsonPathValue(expression, args, Number.class, "a number"));
 	}
@@ -953,6 +957,7 @@ public AbstractObjectAssert<?, Number> extractingJsonPathNumberValue(CharSequenc
 	 * @return a new assertion object whose object under test is the extracted item
 	 * @throws AssertionError if the path is not valid or does not result in a boolean
 	 */
+	@CheckReturnValue
 	public AbstractBooleanAssert<?> extractingJsonPathBooleanValue(CharSequence expression, Object... args) {
 		return Assertions.assertThat(extractingJsonPathValue(expression, args, Boolean.class, "a boolean"));
 	}
@@ -967,6 +972,7 @@ public AbstractBooleanAssert<?> extractingJsonPathBooleanValue(CharSequence expr
 	 * @throws AssertionError if the path is not valid or does not result in an array
 	 */
 	@SuppressWarnings("unchecked")
+	@CheckReturnValue
 	public <E> ListAssert<E> extractingJsonPathArrayValue(CharSequence expression, Object... args) {
 		return Assertions.assertThat(extractingJsonPathValue(expression, args, List.class, "an array"));
 	}
@@ -982,6 +988,7 @@ public <E> ListAssert<E> extractingJsonPathArrayValue(CharSequence expression, O
 	 * @throws AssertionError if the path is not valid or does not result in a map
 	 */
 	@SuppressWarnings("unchecked")
+	@CheckReturnValue
 	public <K, V> MapAssert<K, V> extractingJsonPathMapValue(CharSequence expression, Object... args) {
 		return Assertions.assertThat(extractingJsonPathValue(expression, args, Map.class, "a map"));
 	}

core/spring-boot-test/src/main/java/org/springframework/boot/test/json/ObjectContentAssert.java

@@ -22,6 +22,8 @@
 import org.assertj.core.api.Assert;
 import org.assertj.core.api.InstanceOfAssertFactories;
 
+import org.springframework.lang.CheckReturnValue;
+
 /**
  * AssertJ {@link Assert} for {@link ObjectContent}.
  *
@@ -41,6 +43,7 @@ protected ObjectContentAssert(A actual) {
 	 * allow chaining of array-specific assertions from this call.
 	 * @return an array assertion object
 	 */
+	@CheckReturnValue
 	public AbstractObjectArrayAssert<?, Object> asArray() {
 		return asInstanceOf(InstanceOfAssertFactories.ARRAY);
 	}
@@ -50,6 +53,7 @@ public AbstractObjectArrayAssert<?, Object> asArray() {
 	 * chaining of map-specific assertions from this call.
 	 * @return a map assertion object
 	 */
+	@CheckReturnValue
 	public AbstractMapAssert<?, ?, Object, Object> asMap() {
 		return asInstanceOf(InstanceOfAssertFactories.MAP);
 	}

system-test/spring-boot-image-system-tests/src/systemTest/java/org/springframework/boot/image/assertions/ContainerConfigAssert.java

@@ -32,6 +32,7 @@
 import org.assertj.core.api.ObjectAssert;
 
 import org.springframework.boot.test.json.JsonContentAssert;
+import org.springframework.lang.CheckReturnValue;
 
 /**
  * AssertJ {@link org.assertj.core.api.Assert} for Docker image container configuration.
@@ -89,7 +90,7 @@ protected LabelsAssert(Map<String, String> labels) {
 	/**
 	 * Asserts for the JSON content in the {@code io.buildpacks.build.metadata} label.
 	 *
-	 * See <a href=
+	 * @see <a href=
 	 * "https://github.com/buildpacks/spec/blob/main/platform.md#iobuildpacksbuildmetadata-json">the
 	 * spec</a>
 	 */
@@ -99,10 +100,12 @@ public static class BuildMetadataAssert extends AbstractAssert<BuildMetadataAsse
 			super(jsonContentAssert, BuildMetadataAssert.class);
 		}
 
+		@CheckReturnValue
 		public ListAssert<Object> buildpacks() {
 			return this.actual.extractingJsonPathArrayValue("$.buildpacks[*].id");
 		}
 
+		@CheckReturnValue
 		public AbstractListAssert<?, List<? extends String>, String, ObjectAssert<String>> processOfType(String type) {
 			return this.actual.extractingJsonPathArrayValue("$.processes[?(@.type=='%s')]", type)
 				.singleElement()
@@ -122,7 +125,7 @@ private Collection<String> getArgs(Object obj) {
 	/**
 	 * Asserts for the JSON content in the {@code io.buildpacks.lifecycle.metadata} label.
 	 *
-	 * See <a href=
+	 * @see <a href=
 	 * "https://github.com/buildpacks/spec/blob/main/platform.md#iobuildpackslifecyclemetadata-json">the
 	 * spec</a>
 	 */
@@ -132,14 +135,17 @@ public static class LifecycleMetadataAssert extends AbstractAssert<LifecycleMeta
 			super(jsonContentAssert, LifecycleMetadataAssert.class);
 		}
 
+		@CheckReturnValue
 		public ListAssert<Object> buildpackLayers(String buildpackId) {
 			return this.actual.extractingJsonPathArrayValue("$.buildpacks[?(@.key=='%s')].layers", buildpackId);
 		}
 
+		@CheckReturnValue
 		public AbstractListAssert<?, List<?>, Object, ObjectAssert<Object>> appLayerShas() {
 			return this.actual.extractingJsonPathArrayValue("$.app").extracting("sha");
 		}
 
+		@CheckReturnValue
 		public AbstractObjectAssert<?, Object> sbomLayerSha() {
 			return this.actual.extractingJsonPathValue("$.sbom.sha");
 		}

system-test/spring-boot-image-system-tests/src/systemTest/java/org/springframework/boot/image/assertions/ImageAssert.java

@@ -34,6 +34,7 @@
 import org.springframework.boot.buildpack.platform.docker.type.ImageReference;
 import org.springframework.boot.buildpack.platform.docker.type.Layer;
 import org.springframework.boot.test.json.JsonContentAssert;
+import org.springframework.lang.CheckReturnValue;
 import org.springframework.util.StreamUtils;
 
 /**
@@ -73,6 +74,7 @@ public LayerContentAssert(Layer layer) {
 			super(layer, LayerContentAssert.class);
 		}
 
+		@CheckReturnValue
 		public ListAssert<String> entries() {
 			List<String> entryNames = new ArrayList<>();
 			try {

test-support/spring-boot-test-support/src/main/java/org/springframework/boot/testsupport/assertj/ScheduledExecutorServiceAssert.java

@@ -24,6 +24,7 @@
 import org.assertj.core.api.AbstractAssert;
 import org.assertj.core.api.Assert;
 
+import org.springframework.lang.CheckReturnValue;
 import org.springframework.util.ReflectionUtils;
 
 /**
@@ -85,6 +86,7 @@ private boolean producesVirtualThreads() {
 	 * @param actual the {@link ScheduledExecutorService}
 	 * @return the assertion instance
 	 */
+	@CheckReturnValue
 	public static ScheduledExecutorServiceAssert assertThat(ScheduledExecutorService actual) {
 		return new ScheduledExecutorServiceAssert(actual);
 	}

test-support/spring-boot-test-support/src/main/java/org/springframework/boot/testsupport/assertj/SimpleAsyncTaskExecutorAssert.java

@@ -22,6 +22,7 @@
 import org.assertj.core.api.Assert;
 
 import org.springframework.core.task.SimpleAsyncTaskExecutor;
+import org.springframework.lang.CheckReturnValue;
 import org.springframework.util.ReflectionUtils;
 
 /**
@@ -77,6 +78,7 @@ private boolean producesVirtualThreads() {
 	 * @param actual the {@link SimpleAsyncTaskExecutor}
 	 * @return the assertion instance
 	 */
+	@CheckReturnValue
 	public static SimpleAsyncTaskExecutorAssert assertThat(SimpleAsyncTaskExecutor actual) {
 		return new SimpleAsyncTaskExecutorAssert(actual);
 	}