Fix ControllerAdvice ordering support

Prior to this commit, the `ControllerAdvice` support would detect all
beans and exception handler methods, to put them in an ordered `TreeMap`
using the `OrderComparator.INSTANCE`. Doing so would naturally consider
beans with the same order as duplicates and would write a single entry
in the map. This effectively ignored many `ControllerAdvice` beans with
the same order (but one).

This commit removes the use of a `TreeMap` and instead uses a
`LinkedHashMap` and the insertion order for proper ordering.

Fixes gh-901

spring-graphql/src/main/java/org/springframework/graphql/data/method/annotation/support/AnnotatedControllerExceptionResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -21,9 +21,9 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.TreeMap;
 import java.util.concurrent.ConcurrentHashMap;
 
 import graphql.GraphQLError;
@@ -71,6 +71,7 @@ import org.springframework.web.method.ControllerAdviceBean;
  * non-controller {@link graphql.schema.DataFetcher}s.
  *
  * @author Rossen Stoyanchev
+ * @author Brian Clozel
  * @since 1.2.0
  */
 final class AnnotatedControllerExceptionResolver {
@@ -82,7 +83,7 @@ final class AnnotatedControllerExceptionResolver {
 
 	private final Map<Class<?>, MethodResolver> controllerCache = new ConcurrentHashMap<>(64);
 
-	private final Map<ControllerAdviceBean, MethodResolver> controllerAdviceCache = new TreeMap<>(OrderComparator.INSTANCE);
+	private final Map<ControllerAdviceBean, MethodResolver> controllerAdviceCache = new LinkedHashMap<>();
 
 
 	AnnotatedControllerExceptionResolver(HandlerMethodArgumentResolverComposite resolvers) {
@@ -110,15 +111,19 @@ final class AnnotatedControllerExceptionResolver {
 	 * @param context the context to look into
 	 */
 	public void registerControllerAdvice(ApplicationContext context) {
+		Map<ControllerAdviceBean, MethodResolver> detectedControllerAdvice = new HashMap<>();
 		for (ControllerAdviceBean bean : ControllerAdviceBean.findAnnotatedBeans(context)) {
 			Class<?> beanType = bean.getBeanType();
 			if (beanType != null) {
 				Map<Class<? extends Throwable>, Method> methods = findExceptionHandlers(beanType);
 				if (!methods.isEmpty()) {
-					this.controllerAdviceCache.put(bean, new MethodResolver(methods));
+					detectedControllerAdvice.put(bean, new MethodResolver(methods));
 				}
 			}
 		}
+		detectedControllerAdvice.keySet().stream().sorted(OrderComparator.INSTANCE).forEach(bean -> {
+			this.controllerAdviceCache.put(bean, detectedControllerAdvice.get(bean));
+		});
 		if (logger.isDebugEnabled()) {
 			logger.debug("@GraphQlException methods in ControllerAdvice beans: " +
 					(this.controllerAdviceCache.size() == 0 ? "none" : this.controllerAdviceCache.size()));

spring-graphql/src/test/java/org/springframework/graphql/data/method/annotation/support/AnnotatedControllerExceptionResolverTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -47,7 +47,7 @@ import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
  * Unit tests for {@link AnnotatedControllerExceptionResolver}.
  *
  * @author Rossen Stoyanchev
- * @since 1.2.0
+ * @author Brian Clozel
  */
 public class AnnotatedControllerExceptionResolverTests {
 
@@ -137,6 +137,25 @@ public class AnnotatedControllerExceptionResolverTests {
 		assertThat(actual.get(0).getMessage()).isEqualTo("ordered handle: Bad input");
 	}
 
+	@Test
+	void resolveWithMultipleControllerAdviceAtSameOrder() {
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
+		context.register(TestControllerAdvice.class);
+		context.register(OtherTestControllerAdvice.class);
+		context.refresh();
+
+		Exception ex = new IllegalArgumentException("Bad input");
+		List<GraphQLError> actual = exceptionResolver(context).resolveException(ex, this.environment, null).block();
+		assertThat(actual).hasSize(1);
+		assertThat(actual.get(0).getMessage()).isEqualTo("handle: Bad input");
+
+		ex = new IllegalStateException("Bad state");
+		actual = exceptionResolver(context).resolveException(ex, this.environment, null).block();
+		assertThat(actual).hasSize(1);
+		assertThat(actual.get(0).getMessage()).isEqualTo("handle: Bad state");
+	}
+
+
 	@Test
 	void invalidReturnType() {
 		assertThatIllegalStateException().isThrownBy(() ->
@@ -250,6 +269,17 @@ public class AnnotatedControllerExceptionResolverTests {
 
 	}
 
+	@SuppressWarnings("unused")
+	@ControllerAdvice
+	private static class OtherTestControllerAdvice {
+
+		@GraphQlExceptionHandler
+		GraphQLError handle(IllegalStateException ex) {
+			return GraphQLError.newError().message("handle: " + ex.getMessage()).build();
+		}
+
+	}
+
 
 	@SuppressWarnings("unused")
 	@ControllerAdvice