Remove error message attribute instead of blanking it when not included

Closes gh-24712

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/web/servlet/ManagementErrorEndpointTests.java

@@ -55,7 +55,7 @@ class ManagementErrorEndpointTests {
 	void errorResponseNeverDetails() {
 		ManagementErrorEndpoint endpoint = new ManagementErrorEndpoint(this.errorAttributes, this.errorProperties);
 		Map<String, Object> response = endpoint.invoke(new ServletWebRequest(new MockHttpServletRequest()));
-		assertThat(response).containsEntry("message", "");
+		assertThat(response).doesNotContainKey("message");
 		assertThat(response).doesNotContainKey("trace");
 	}
 
@@ -78,7 +78,7 @@ class ManagementErrorEndpointTests {
 		this.errorProperties.setIncludeMessage(ErrorProperties.IncludeAttribute.ON_PARAM);
 		ManagementErrorEndpoint endpoint = new ManagementErrorEndpoint(this.errorAttributes, this.errorProperties);
 		Map<String, Object> response = endpoint.invoke(new ServletWebRequest(this.request));
-		assertThat(response).containsEntry("message", "");
+		assertThat(response).doesNotContainKey("message");
 		assertThat(response).doesNotContainKey("trace");
 	}
 
@@ -103,7 +103,7 @@ class ManagementErrorEndpointTests {
 		this.request.addParameter("message", "false");
 		ManagementErrorEndpoint endpoint = new ManagementErrorEndpoint(this.errorAttributes, this.errorProperties);
 		Map<String, Object> response = endpoint.invoke(new ServletWebRequest(this.request));
-		assertThat(response).containsEntry("message", "");
+		assertThat(response).doesNotContainKey("message");
 		assertThat(response).doesNotContainKey("trace");
 	}
 

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

@@ -87,8 +87,8 @@ class DefaultErrorWebExceptionHandlerIntegrationTests {
 			client.get().uri("/").exchange().expectStatus().isEqualTo(HttpStatus.INTERNAL_SERVER_ERROR).expectBody()
 					.jsonPath("status").isEqualTo("500").jsonPath("error")
 					.isEqualTo(HttpStatus.INTERNAL_SERVER_ERROR.getReasonPhrase()).jsonPath("path").isEqualTo(("/"))
-					.jsonPath("message").isEmpty().jsonPath("exception").doesNotExist().jsonPath("trace").doesNotExist()
-					.jsonPath("requestId").isEqualTo(this.logIdFilter.getLogId());
+					.jsonPath("message").doesNotExist().jsonPath("exception").doesNotExist().jsonPath("trace")
+					.doesNotExist().jsonPath("requestId").isEqualTo(this.logIdFilter.getLogId());
 			assertThat(output).contains("500 Server Error for HTTP GET \"/\"")
 					.contains("java.lang.IllegalStateException: Expected!");
 		});
@@ -124,7 +124,7 @@ class DefaultErrorWebExceptionHandlerIntegrationTests {
 					.isBadRequest().expectBody().jsonPath("status").isEqualTo("400").jsonPath("error")
 					.isEqualTo(HttpStatus.BAD_REQUEST.getReasonPhrase()).jsonPath("path").isEqualTo(("/bind"))
 					.jsonPath("exception").doesNotExist().jsonPath("errors").doesNotExist().jsonPath("message")
-					.isEmpty().jsonPath("requestId").isEqualTo(this.logIdFilter.getLogId());
+					.doesNotExist().jsonPath("requestId").isEqualTo(this.logIdFilter.getLogId());
 		});
 	}
 
@@ -227,7 +227,7 @@ class DefaultErrorWebExceptionHandlerIntegrationTests {
 							.isEqualTo(HttpStatus.INTERNAL_SERVER_ERROR).expectBody().jsonPath("status")
 							.isEqualTo("500").jsonPath("error")
 							.isEqualTo(HttpStatus.INTERNAL_SERVER_ERROR.getReasonPhrase()).jsonPath("exception")
-							.isEqualTo(IllegalStateException.class.getName()).jsonPath("message").isEmpty()
+							.isEqualTo(IllegalStateException.class.getName()).jsonPath("message").doesNotExist()
 							.jsonPath("requestId").isEqualTo(this.logIdFilter.getLogId());
 				});
 	}

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

@@ -88,7 +88,7 @@ class BasicErrorControllerIntegrationTests {
 	void testErrorForMachineClientDefault() {
 		load();
 		ResponseEntity<Map> entity = new TestRestTemplate().getForEntity(createUrl("?trace=true"), Map.class);
-		assertErrorAttributes(entity.getBody(), "500", "Internal Server Error", null, "", "/");
+		assertErrorAttributes(entity.getBody(), "500", "Internal Server Error", null, null, "/");
 		assertThat(entity.getBody()).doesNotContainKey("exception");
 		assertThat(entity.getBody()).doesNotContainKey("trace");
 	}
@@ -148,7 +148,7 @@ class BasicErrorControllerIntegrationTests {
 	@SuppressWarnings({ "rawtypes", "unchecked" })
 	private void exceptionWithoutStackTraceAndMessage(String path) {
 		ResponseEntity<Map> entity = new TestRestTemplate().getForEntity(createUrl(path), Map.class);
-		assertErrorAttributes(entity.getBody(), "500", "Internal Server Error", IllegalStateException.class, "", "/");
+		assertErrorAttributes(entity.getBody(), "500", "Internal Server Error", IllegalStateException.class, null, "/");
 		assertThat(entity.getBody()).doesNotContainKey("trace");
 	}
 
@@ -158,7 +158,7 @@ class BasicErrorControllerIntegrationTests {
 		load("--server.error.include-exception=true");
 		ResponseEntity<Map> entity = new TestRestTemplate().getForEntity(createUrl("/annotated"), Map.class);
 		assertErrorAttributes(entity.getBody(), "400", "Bad Request", TestConfiguration.Errors.ExpectedException.class,
-				"", "/annotated");
+				null, "/annotated");
 	}
 
 	@Test
@@ -176,7 +176,7 @@ class BasicErrorControllerIntegrationTests {
 		load("--server.error.include-exception=true");
 		ResponseEntity<Map> entity = new TestRestTemplate().getForEntity(createUrl("/annotatedNoReason"), Map.class);
 		assertErrorAttributes(entity.getBody(), "406", "Not Acceptable",
-				TestConfiguration.Errors.NoReasonExpectedException.class, "", "/annotatedNoReason");
+				TestConfiguration.Errors.NoReasonExpectedException.class, null, "/annotatedNoReason");
 	}
 
 	@Test
@@ -261,14 +261,14 @@ class BasicErrorControllerIntegrationTests {
 	@SuppressWarnings({ "rawtypes", "unchecked" })
 	private void bindingExceptionWithErrors(String param) {
 		ResponseEntity<Map> entity = new TestRestTemplate().getForEntity(createUrl("/bind" + param), Map.class);
-		assertErrorAttributes(entity.getBody(), "400", "Bad Request", BindException.class, "", "/bind");
+		assertErrorAttributes(entity.getBody(), "400", "Bad Request", BindException.class, null, "/bind");
 		assertThat(entity.getBody()).containsKey("errors");
 	}
 
 	@SuppressWarnings({ "rawtypes", "unchecked" })
 	private void bindingExceptionWithoutErrors(String param) {
 		ResponseEntity<Map> entity = new TestRestTemplate().getForEntity(createUrl("/bind" + param), Map.class);
-		assertErrorAttributes(entity.getBody(), "400", "Bad Request", BindException.class, "", "/bind");
+		assertErrorAttributes(entity.getBody(), "400", "Bad Request", BindException.class, null, "/bind");
 		assertThat(entity.getBody()).doesNotContainKey("errors");
 	}
 
@@ -283,7 +283,7 @@ class BasicErrorControllerIntegrationTests {
 	@SuppressWarnings({ "rawtypes", "unchecked" })
 	private void bindingExceptionWithoutMessage(String param) {
 		ResponseEntity<Map> entity = new TestRestTemplate().getForEntity(createUrl("/bind" + param), Map.class);
-		assertErrorAttributes(entity.getBody(), "400", "Bad Request", BindException.class, "", "/bind");
+		assertErrorAttributes(entity.getBody(), "400", "Bad Request", BindException.class, null, "/bind");
 		assertThat(entity.getBody()).doesNotContainKey("errors");
 	}
 
@@ -294,7 +294,7 @@ class BasicErrorControllerIntegrationTests {
 		RequestEntity request = RequestEntity.post(URI.create(createUrl("/bodyValidation")))
 				.accept(MediaType.APPLICATION_JSON).contentType(MediaType.APPLICATION_JSON).body("{}");
 		ResponseEntity<Map> entity = new TestRestTemplate().exchange(request, Map.class);
-		assertErrorAttributes(entity.getBody(), "400", "Bad Request", MethodArgumentNotValidException.class, "",
+		assertErrorAttributes(entity.getBody(), "400", "Bad Request", MethodArgumentNotValidException.class, null,
 				"/bodyValidation");
 		assertThat(entity.getBody()).doesNotContainKey("errors");
 	}

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

@@ -73,7 +73,7 @@ public class DefaultErrorAttributes implements ErrorAttributes {
 			errorAttributes.remove("trace");
 		}
 		if (!options.isIncluded(Include.MESSAGE) && errorAttributes.get("message") != null) {
-			errorAttributes.put("message", "");
+			errorAttributes.remove("message");
 		}
 		if (!options.isIncluded(Include.BINDING_ERRORS)) {
 			errorAttributes.remove("errors");

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

@@ -96,7 +96,7 @@ public class DefaultErrorAttributes implements ErrorAttributes, HandlerException
 			errorAttributes.remove("trace");
 		}
 		if (!options.isIncluded(Include.MESSAGE) && errorAttributes.get("message") != null) {
-			errorAttributes.put("message", "");
+			errorAttributes.remove("message");
 		}
 		if (!options.isIncluded(Include.BINDING_ERRORS)) {
 			errorAttributes.remove("errors");

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

@@ -93,7 +93,7 @@ class DefaultErrorAttributesTests {
 		Map<String, Object> attributes = this.errorAttributes.getErrorAttributes(buildServerRequest(request, error),
 				ErrorAttributeOptions.defaults());
 		assertThat(attributes.get("error")).isEqualTo(HttpStatus.I_AM_A_TEAPOT.getReasonPhrase());
-		assertThat(attributes.get("message")).isEqualTo("");
+		assertThat(attributes).doesNotContainKey("message");
 		assertThat(attributes.get("status")).isEqualTo(HttpStatus.I_AM_A_TEAPOT.value());
 	}
 
@@ -148,7 +148,7 @@ class DefaultErrorAttributesTests {
 		Map<String, Object> attributes = this.errorAttributes.getErrorAttributes(serverRequest,
 				ErrorAttributeOptions.defaults());
 		assertThat(this.errorAttributes.getError(serverRequest)).isSameAs(error);
-		assertThat(attributes.get("message")).isEqualTo("");
+		assertThat(attributes).doesNotContainKey("message");
 	}
 
 	@Test
@@ -256,7 +256,7 @@ class DefaultErrorAttributesTests {
 		MockServerHttpRequest request = MockServerHttpRequest.get("/test").build();
 		Map<String, Object> attributes = this.errorAttributes.getErrorAttributes(buildServerRequest(request, ex),
 				ErrorAttributeOptions.defaults());
-		assertThat(attributes).containsEntry("message", "");
+		assertThat(attributes).doesNotContainKey("message");
 		assertThat(attributes).doesNotContainKey("errors");
 	}
 

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

@@ -113,7 +113,7 @@ class DefaultErrorAttributesTests {
 				ErrorAttributeOptions.defaults());
 		assertThat(this.errorAttributes.getError(this.webRequest)).isSameAs(ex);
 		assertThat(attributes).doesNotContainKey("exception");
-		assertThat(attributes.get("message").toString()).contains("");
+		assertThat(attributes).doesNotContainKey("message");
 	}
 
 	@Test
@@ -131,7 +131,7 @@ class DefaultErrorAttributesTests {
 		Map<String, Object> attributes = this.errorAttributes.getErrorAttributes(this.webRequest,
 				ErrorAttributeOptions.defaults());
 		assertThat(attributes).doesNotContainKey("exception");
-		assertThat(attributes.get("message")).asString().contains("");
+		assertThat(attributes).doesNotContainKey("message");
 	}
 
 	@Test
@@ -210,7 +210,7 @@ class DefaultErrorAttributesTests {
 					.isEqualTo("Validation failed for object='objectName'. Error count: 1");
 		}
 		else {
-			assertThat(attributes.get("message")).isEqualTo("");
+			assertThat(attributes).doesNotContainKey("message");
 		}
 		if (options.isIncluded(Include.BINDING_ERRORS)) {
 			assertThat(attributes.get("errors")).isEqualTo(bindingResult.getAllErrors());