Improve Error Message for Conflicting Filter Chains

Closes gh-15874

Author: jzheaux

config/src/main/java/org/springframework/security/config/annotation/web/builders/WebSecurity.java

@@ -302,16 +302,16 @@ protected Filter performBuild() throws Exception {
 			requestMatcherPrivilegeEvaluatorsEntries
 				.add(getRequestMatcherPrivilegeEvaluatorsEntry(securityFilterChain));
 		}
-		boolean anyRequestConfigured = false;
+		DefaultSecurityFilterChain anyRequestConfigured = null;
 		for (SecurityBuilder<? extends SecurityFilterChain> securityFilterChainBuilder : this.securityFilterChainBuilders) {
 			SecurityFilterChain securityFilterChain = securityFilterChainBuilder.build();
-			Assert.isTrue(!anyRequestConfigured,
-					"A filter chain that matches any request has already been configured, which means that this filter chain ["
-							+ securityFilterChain
-							+ "] will never get invoked. Please use `HttpSecurity#securityMatcher` to ensure that there is only one filter chain configured for 'any request' and that the 'any request' filter chain is published last.");
+			Assert.isTrue(anyRequestConfigured == null, "A filter chain that matches any request ["
+					+ anyRequestConfigured + "] has already been configured, which means that this filter chain ["
+					+ securityFilterChain
+					+ "] will never get invoked. Please use `HttpSecurity#securityMatcher` to ensure that there is only one filter chain configured for 'any request' and that the 'any request' filter chain is published last.");
 			if (securityFilterChain instanceof DefaultSecurityFilterChain defaultSecurityFilterChain) {
 				if (defaultSecurityFilterChain.getRequestMatcher() instanceof AnyRequestMatcher) {
-					anyRequestConfigured = true;
+					anyRequestConfigured = defaultSecurityFilterChain;
 				}
 			}
 			securityFilterChains.add(securityFilterChain);

web/src/main/java/org/springframework/security/web/DefaultSecurityFilterChain.java

@@ -24,7 +24,9 @@
 import jakarta.servlet.http.HttpServletRequest;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import reactor.util.annotation.NonNull;
 
+import org.springframework.beans.factory.BeanNameAware;
 import org.springframework.core.log.LogMessage;
 import org.springframework.security.web.util.matcher.RequestMatcher;
 import org.springframework.util.StringUtils;
@@ -36,14 +38,16 @@
  * @author Jinwoo Bae
  * @since 3.1
  */
-public final class DefaultSecurityFilterChain implements SecurityFilterChain {
+public final class DefaultSecurityFilterChain implements SecurityFilterChain, BeanNameAware {
 
 	private static final Log logger = LogFactory.getLog(DefaultSecurityFilterChain.class);
 
 	private final RequestMatcher requestMatcher;
 
 	private final List<Filter> filters;
 
+	private String beanName;
+
 	public DefaultSecurityFilterChain(RequestMatcher requestMatcher, Filter... filters) {
 		this(requestMatcher, Arrays.asList(filters));
 	}
@@ -80,8 +84,24 @@ public boolean matches(HttpServletRequest request) {
 
 	@Override
 	public String toString() {
-		return this.getClass().getSimpleName() + " [RequestMatcher=" + this.requestMatcher + ", Filters=" + this.filters
-				+ "]";
+		List<String> filterNames = new ArrayList<>();
+		for (Filter filter : this.filters) {
+			String name = filter.getClass().getSimpleName();
+			if (name.endsWith("Filter")) {
+				name = name.substring(0, name.length() - "Filter".length());
+			}
+			filterNames.add(name);
+		}
+		String declaration = this.getClass().getSimpleName();
+		if (this.beanName != null) {
+			declaration += " defined as '" + this.beanName + "'";
+		}
+		return declaration + " matching [" + this.requestMatcher + "] and having filters " + filterNames;
+	}
+
+	@Override
+	public void setBeanName(@NonNull String name) {
+		this.beanName = name;
 	}
 
 }