From 1f5344dc27a959648fd74d114ad9403f47ac1de5 Mon Sep 17 00:00:00 2001
From: Jay Choi <jayyoungchoi22@gmail.com>
Date: Tue, 10 Feb 2026 22:46:22 +0900
Subject: [PATCH] Register ErrorPageRegistrarBeanPostProcessor in war
 deployments

Closes gh-49148

Signed-off-by: Jay Choi <jayyoungchoi22@gmail.com>
---
 .../support/ErrorPageFilterConfiguration.java   |  7 +++++++
 .../SpringBootServletInitializerTests.java      | 17 +++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/core/spring-boot/src/main/java/org/springframework/boot/web/servlet/support/ErrorPageFilterConfiguration.java b/core/spring-boot/src/main/java/org/springframework/boot/web/servlet/support/ErrorPageFilterConfiguration.java
index d980979368dd..c478dbfc6465 100644
--- a/core/spring-boot/src/main/java/org/springframework/boot/web/servlet/support/ErrorPageFilterConfiguration.java
+++ b/core/spring-boot/src/main/java/org/springframework/boot/web/servlet/support/ErrorPageFilterConfiguration.java
@@ -18,6 +18,7 @@
 
 import jakarta.servlet.DispatcherType;
 
+import org.springframework.boot.web.error.ErrorPageRegistrarBeanPostProcessor;
 import org.springframework.boot.web.servlet.FilterRegistrationBean;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -26,6 +27,7 @@
  * Configuration for {@link ErrorPageFilter}.
  *
  * @author Andy Wilkinson
+ * @author Jay Choi
  */
 @Configuration(proxyBeanMethods = false)
 class ErrorPageFilterConfiguration {
@@ -43,4 +45,9 @@ FilterRegistrationBean<ErrorPageFilter> errorPageFilterRegistration(ErrorPageFil
 		return registration;
 	}
 
+	@Bean
+	static ErrorPageRegistrarBeanPostProcessor errorPageRegistrarBeanPostProcessor() {
+		return new ErrorPageRegistrarBeanPostProcessor();
+	}
+
 }
diff --git a/core/spring-boot/src/test/java/org/springframework/boot/web/servlet/support/SpringBootServletInitializerTests.java b/core/spring-boot/src/test/java/org/springframework/boot/web/servlet/support/SpringBootServletInitializerTests.java
index 5c86176f9220..8c2b756ddb02 100644
--- a/core/spring-boot/src/test/java/org/springframework/boot/web/servlet/support/SpringBootServletInitializerTests.java
+++ b/core/spring-boot/src/test/java/org/springframework/boot/web/servlet/support/SpringBootServletInitializerTests.java
@@ -41,6 +41,7 @@
 import org.springframework.boot.context.logging.LoggingApplicationListener;
 import org.springframework.boot.testsupport.system.CapturedOutput;
 import org.springframework.boot.testsupport.system.OutputCaptureExtension;
+import org.springframework.boot.web.error.ErrorPageRegistrarBeanPostProcessor;
 import org.springframework.boot.web.servlet.FilterRegistrationBean;
 import org.springframework.context.ApplicationListener;
 import org.springframework.context.ConfigurableApplicationContext;
@@ -66,6 +67,7 @@
  *
  * @author Phillip Webb
  * @author Andy Wilkinson
+ * @author Jay Choi
  */
 @ExtendWith(OutputCaptureExtension.class)
 class SpringBootServletInitializerTests {
@@ -135,6 +137,21 @@ void errorPageFilterRegistrationCanBeDisabled() {
 		}
 	}
 
+	@Test
+	void errorPageRegistrarBeanPostProcessorIsRegistered() {
+		ServletContext servletContext = mock(ServletContext.class);
+		given(servletContext.addFilter(any(), any(Filter.class))).willReturn(mock(Dynamic.class));
+		given(servletContext.getInitParameterNames()).willReturn(Collections.emptyEnumeration());
+		given(servletContext.getAttributeNames()).willReturn(Collections.emptyEnumeration());
+		try (AbstractApplicationContext context = (AbstractApplicationContext) new WithErrorPageFilter()
+			.createRootApplicationContext(servletContext)) {
+			assertThat(context).isNotNull();
+			Map<String, ErrorPageRegistrarBeanPostProcessor> beans = context
+				.getBeansOfType(ErrorPageRegistrarBeanPostProcessor.class);
+			assertThat(beans).hasSize(1);
+		}
+	}
+
 	@Test
 	@SuppressWarnings("rawtypes")
 	void errorPageFilterIsRegisteredWithNearHighestPrecedence() {