Remove ErrorAttributes.ERROR_ATTRIBUTE

This commit removes the now defunkt `ErrorAttributes.ERROR_ATTRIBUTE`
that was introduce to register handled errors as metrics. This has been
replaced since 3.0 by a direct support in Spring Framework and had no
effect whatsoever since that release.

This also updates the documentation to point to the Framework mechanism
that replaced it.

Fixes gh-33731

spring-boot-project/spring-boot-docs/src/docs/asciidoc/web/reactive.adoc

@@ -189,10 +189,8 @@ include::code:MyErrorWebExceptionHandler[]
 
 For a more complete picture, you can also subclass `DefaultErrorWebExceptionHandler` directly and override specific methods.
 
-In some cases, errors handled at the controller or handler function level are not recorded by the <<actuator#actuator.metrics.supported.spring-webflux, metrics infrastructure>>.
-Applications can ensure that such exceptions are recorded with the request metrics by setting the handled exception as a request attribute:
-
-include::code:MyExceptionHandlingController[]
+In some cases, errors handled at the controller level are not recorded by web observations or the <<actuator#actuator.metrics.supported.spring-webflux, metrics infrastructure>>.
+Applications can ensure that such exceptions are recorded with the observations by {spring-framework-docs}/integration/observability.html#observability.http-server.reactive[setting the handled exception on the observation context].
 
 
 

spring-boot-project/spring-boot-docs/src/docs/asciidoc/web/servlet.adoc

@@ -355,10 +355,8 @@ include::code:MyControllerAdvice[]
 
 In the preceding example, if `MyException` is thrown by a controller defined in the same package as `SomeController`, a JSON representation of the `MyErrorBody` POJO is used instead of the `ErrorAttributes` representation.
 
-In some cases, errors handled at the controller level are not recorded by the <<actuator#actuator.metrics.supported.spring-mvc, metrics infrastructure>>.
-Applications can ensure that such exceptions are recorded with the request metrics by setting the handled exception as a request attribute:
-
-include::code:MyController[]
+In some cases, errors handled at the controller level are not recorded by web observations or the <<actuator#actuator.metrics.supported.spring-mvc, metrics infrastructure>>.
+Applications can ensure that such exceptions are recorded with the observations by {spring-framework-docs}/integration/observability.html#observability.http-server.servlet[setting the handled exception on the observation context].
 
 
 

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/reactive/error/DefaultErrorAttributes.java

@@ -152,7 +152,6 @@ private void handleException(Map<String, Object> errorAttributes, Throwable erro
 	@Override
 	public Throwable getError(ServerRequest request) {
 		Optional<Object> error = request.attribute(ERROR_INTERNAL_ATTRIBUTE);
-		error.ifPresent((value) -> request.attributes().putIfAbsent(ErrorAttributes.ERROR_ATTRIBUTE, value));
 		return (Throwable) error
 			.orElseThrow(() -> new IllegalStateException("Missing exception attribute in ServerWebExchange"));
 	}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/reactive/error/ErrorAttributes.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2023 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.
@@ -34,13 +34,6 @@
  */
 public interface ErrorAttributes {
 
-	/**
-	 * Name of the {@link ServerRequest#attribute(String) request attribute} holding the
-	 * error resolved by the {@code ErrorAttributes} implementation.
-	 * @since 2.5.0
-	 */
-	String ERROR_ATTRIBUTE = ErrorAttributes.class.getName() + ".error";
-
 	/**
 	 * Return a {@link Map} of the error attributes. The map can be used as the model of
 	 * an error page, or returned as a {@link ServerResponse} body.

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/servlet/error/DefaultErrorAttributes.java

@@ -216,9 +216,6 @@ public Throwable getError(WebRequest webRequest) {
 		if (exception == null) {
 			exception = getAttribute(webRequest, RequestDispatcher.ERROR_EXCEPTION);
 		}
-		// store the exception in a well-known attribute to make it available to metrics
-		// instrumentation.
-		webRequest.setAttribute(ErrorAttributes.ERROR_ATTRIBUTE, exception, WebRequest.SCOPE_REQUEST);
 		return exception;
 	}
 

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/servlet/error/ErrorAttributes.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2023 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.
@@ -34,14 +34,6 @@
  */
 public interface ErrorAttributes {
 
-	/**
-	 * Name of the {@link jakarta.servlet.http.HttpServletRequest#getAttribute(String)
-	 * request attribute} holding the error resolved by the {@code ErrorAttributes}
-	 * implementation.
-	 * @since 2.5.0
-	 */
-	String ERROR_ATTRIBUTE = ErrorAttributes.class.getName() + ".error";
-
 	/**
 	 * Returns a {@link Map} of the error attributes. The map can be used as the model of
 	 * an error page {@link ModelAndView}, or returned as a

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/reactive/error/DefaultErrorAttributesTests.java

@@ -160,7 +160,6 @@ void includeException() {
 		Map<String, Object> attributes = this.errorAttributes.getErrorAttributes(serverRequest,
 				ErrorAttributeOptions.of(Include.EXCEPTION, Include.MESSAGE));
 		assertThat(this.errorAttributes.getError(serverRequest)).isSameAs(error);
-		assertThat(serverRequest.attribute(ErrorAttributes.ERROR_ATTRIBUTE)).containsSame(error);
 		assertThat(attributes).containsEntry("exception", RuntimeException.class.getName());
 		assertThat(attributes).containsEntry("message", "Test");
 	}
@@ -178,7 +177,6 @@ void processResponseStatusException() {
 		assertThat(attributes).containsEntry("message", "invalid request");
 		assertThat(attributes).containsEntry("exception", RuntimeException.class.getName());
 		assertThat(this.errorAttributes.getError(serverRequest)).isSameAs(error);
-		assertThat(serverRequest.attribute(ErrorAttributes.ERROR_ATTRIBUTE)).containsSame(error);
 	}
 
 	@Test
@@ -194,7 +192,6 @@ void processResponseStatusExceptionWithNoNestedCause() {
 		assertThat(attributes).containsEntry("message", "could not process request");
 		assertThat(attributes).containsEntry("exception", ResponseStatusException.class.getName());
 		assertThat(this.errorAttributes.getError(serverRequest)).isSameAs(error);
-		assertThat(serverRequest.attribute(ErrorAttributes.ERROR_ATTRIBUTE)).containsSame(error);
 	}
 
 	@Test

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/servlet/error/DefaultErrorAttributesTests.java

@@ -88,8 +88,6 @@ void mvcError() {
 		Map<String, Object> attributes = this.errorAttributes.getErrorAttributes(this.webRequest,
 				ErrorAttributeOptions.of(Include.MESSAGE));
 		assertThat(this.errorAttributes.getError(this.webRequest)).isSameAs(ex);
-		assertThat(this.webRequest.getAttribute(ErrorAttributes.ERROR_ATTRIBUTE, WebRequest.SCOPE_REQUEST))
-			.isSameAs(ex);
 		assertThat(modelAndView).isNull();
 		assertThat(attributes).doesNotContainKey("exception");
 		assertThat(attributes).containsEntry("message", "Test");
@@ -102,8 +100,6 @@ void servletErrorWithMessage() {
 		Map<String, Object> attributes = this.errorAttributes.getErrorAttributes(this.webRequest,
 				ErrorAttributeOptions.of(Include.MESSAGE));
 		assertThat(this.errorAttributes.getError(this.webRequest)).isSameAs(ex);
-		assertThat(this.webRequest.getAttribute(ErrorAttributes.ERROR_ATTRIBUTE, WebRequest.SCOPE_REQUEST))
-			.isSameAs(ex);
 		assertThat(attributes).doesNotContainKey("exception");
 		assertThat(attributes).containsEntry("message", "Test");
 	}
@@ -115,8 +111,6 @@ void servletErrorWithoutMessage() {
 		Map<String, Object> attributes = this.errorAttributes.getErrorAttributes(this.webRequest,
 				ErrorAttributeOptions.defaults());
 		assertThat(this.errorAttributes.getError(this.webRequest)).isSameAs(ex);
-		assertThat(this.webRequest.getAttribute(ErrorAttributes.ERROR_ATTRIBUTE, WebRequest.SCOPE_REQUEST))
-			.isSameAs(ex);
 		assertThat(attributes).doesNotContainKey("exception");
 		assertThat(attributes).doesNotContainKey("message");
 	}
@@ -166,8 +160,6 @@ void unwrapServletException() {
 		Map<String, Object> attributes = this.errorAttributes.getErrorAttributes(this.webRequest,
 				ErrorAttributeOptions.of(Include.MESSAGE));
 		assertThat(this.errorAttributes.getError(this.webRequest)).isSameAs(wrapped);
-		assertThat(this.webRequest.getAttribute(ErrorAttributes.ERROR_ATTRIBUTE, WebRequest.SCOPE_REQUEST))
-			.isSameAs(wrapped);
 		assertThat(attributes).doesNotContainKey("exception");
 		assertThat(attributes).containsEntry("message", "Test");
 	}
@@ -179,8 +171,6 @@ void getError() {
 		Map<String, Object> attributes = this.errorAttributes.getErrorAttributes(this.webRequest,
 				ErrorAttributeOptions.of(Include.MESSAGE));
 		assertThat(this.errorAttributes.getError(this.webRequest)).isSameAs(error);
-		assertThat(this.webRequest.getAttribute(ErrorAttributes.ERROR_ATTRIBUTE, WebRequest.SCOPE_REQUEST))
-			.isSameAs(error);
 		assertThat(attributes).doesNotContainKey("exception");
 		assertThat(attributes).containsEntry("message", "Test error");
 	}