SchemaMappingInspector supports Boolean is<PropertyName>

Closes gh-1332

Author: rstoyanchev

spring-graphql/src/main/java/org/springframework/graphql/execution/SchemaMappingInspector.java

@@ -94,6 +94,7 @@ public final class SchemaMappingInspector {
 			(!method.getDeclaringClass().equals(Object.class) && !method.getReturnType().equals(Void.class) &&
 					method.getParameterCount() == 0 && Modifier.isPublic(method.getModifiers()));
 
+
 	private final GraphQLSchema schema;
 
 	private final Map<String, Map<String, DataFetcher>> dataFetchers;
@@ -191,8 +192,8 @@ private void checkFieldsContainer(
 					checkField(fieldContainer, field, ResolvableType.forField(javaField));
 					continue;
 				}
-				// Kotlin function?
-				Method method = getRecordLikeMethod(resolvableType, fieldName);
+				// Kotlin function, Boolean is<PropertyName>
+				Method method = getOtherAccessor(resolvableType, fieldName);
 				if (method != null) {
 					MethodParameter returnType = new MethodParameter(method, -1);
 					checkField(fieldContainer, field, ResolvableType.forMethodParameter(returnType, resolvableType));
@@ -286,13 +287,18 @@ private Field getField(ResolvableType resolvableType, String fieldName) {
 	}
 
 	@Nullable
-	private static Method getRecordLikeMethod(ResolvableType resolvableType, String fieldName) {
+	private static Method getOtherAccessor(ResolvableType resolvableType, String fieldName) {
 		Class<?> clazz = resolvableType.resolve();
 		if (clazz != null) {
 			for (Method method : clazz.getDeclaredMethods()) {
 				if (recordLikePredicate.test(method) && fieldName.equals(StringUtils.uncapitalize(method.getName()))) {
 					return method;
 				}
+				// JavaBean introspection supports boolean property only
+				if (method.getReturnType().equals(Boolean.class) &&
+						method.getName().equals("is" + StringUtils.capitalize(fieldName))) {
+					return method;
+				}
 			}
 		}
 		return null;

spring-graphql/src/test/java/org/springframework/graphql/execution/SchemaMappingInspectorTests.java

@@ -380,6 +380,20 @@ void reportIsEmptyWhenFieldHasBatchMapping() {
 			assertThatReport(report).hasUnmappedFieldCount(0).hasSkippedTypeCount(0);
 		}
 
+		@Test // gh-1332
+		void reportIsEmptyWithBooleanProperty() {
+			String schema = """
+						type Query {
+							user: User!
+						}
+						type User {
+							allowed: Boolean!
+						}
+					""";
+			SchemaReport report = inspectSchema(schema, UserController.class);
+			assertThatReport(report).hasUnmappedFieldCount(0).hasSkippedTypeCount(0);
+		}
+
 		@Test
 		void reportHasUnmappedField() {
 			String schema = """
@@ -736,4 +750,29 @@ record ListContainer<T>(List<T> items) {
 
 	}
 
+
+	@Controller
+	static class UserController {
+
+		@QueryMapping
+		User user() {
+			return new User(true);
+		}
+
+	}
+
+
+	static class User {
+
+		private final Boolean allowed;
+
+		User(Boolean allowed) {
+			this.allowed = allowed;
+		}
+
+		public Boolean isAllowed() {
+			return allowed;
+		}
+	}
+
 }