Improve paginated type check in schema inspection

Closes gh-1053

Author: rstoyanchev

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

@@ -684,8 +684,9 @@ public static TypePair resolveTypePair(
 
 			// Remove GraphQL type wrappers, and nest within Java generic types
 			GraphQLType outputType = unwrapIfNonNull(field.getType());
-			if (isPaginatedType(outputType)) {
-				outputType = getPaginatedType((GraphQLObjectType) outputType, schema);
+			GraphQLType paginatedType = getPaginatedType(outputType);
+			if (paginatedType != null) {
+				outputType = paginatedType;
 				resolvableType = nestForConnection(resolvableType);
 			}
 			else if (outputType instanceof GraphQLList listType) {
@@ -702,17 +703,26 @@ private static GraphQLType unwrapIfNonNull(GraphQLType type) {
 			return (type instanceof GraphQLNonNull graphQLNonNull) ? graphQLNonNull.getWrappedType() : type;
 		}
 
-		private static boolean isPaginatedType(GraphQLType type) {
-			return (type instanceof GraphQLObjectType objectType &&
-					objectType.getName().endsWith("Connection") &&
-					objectType.getField("edges") != null && objectType.getField("pageInfo") != null);
-		}
-
-		private static GraphQLType getPaginatedType(GraphQLObjectType type, GraphQLSchema schema) {
-			String name = type.getName().substring(0, type.getName().length() - 10);
-			GraphQLType nodeType = schema.getType(name);
-			Assert.state(nodeType != null, "No node type for '" + type.getName() + "'");
-			return nodeType;
+		@Nullable
+		private static GraphQLType getPaginatedType(GraphQLType type) {
+			if (!(type instanceof GraphQLObjectType cot && cot.getName().endsWith("Connection"))) {
+				return null;
+			}
+			GraphQLFieldDefinition edges = cot.getField("edges");
+			if (edges == null) {
+				return null;
+			}
+			if (!(unwrapIfNonNull(edges.getType()) instanceof GraphQLList lt)) {
+				return null;
+			}
+			if (!(lt.getWrappedType() instanceof GraphQLObjectType eot)) {
+				return null;
+			}
+			GraphQLFieldDefinition node = eot.getField("node");
+			if (node == null) {
+				return null;
+			}
+			return unwrapIfNonNull(node.getType());
 		}
 
 		private static ResolvableType nestForConnection(ResolvableType type) {

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

@@ -113,7 +113,7 @@ void reportWorksForQueryWithOptional() {
 		}
 
 		@Test
-		void reportWorksForQueryWithConnection() {
+		void reportWorksForConnectionType() {
 			String schema = """
 						type Query {
 							paginatedBooks: BookConnection
@@ -124,7 +124,7 @@ void reportWorksForQueryWithConnection() {
 						}
 						type BookEdge {
 							cursor: String!
-							# ...
+							node: Book!
 						}
 						type PageInfo {
 							startCursor: String
@@ -140,6 +140,34 @@ void reportWorksForQueryWithConnection() {
 			assertThatReport(report).hasUnmappedFieldCount(1).containsUnmappedFields("Book", "missing");
 		}
 
+		@Test // gh-1053
+		void reportWorksForConnectionWithCustomNodeTypeName() {
+			String schema = """
+						type Query {
+							paginatedBooks: BookConnection
+						}
+						type BookConnection {
+							edges: [BookEdge]!
+							pageInfo: PageInfo!
+						}
+						type BookEdge {
+							cursor: String!
+							node: MyBook!
+						}
+						type PageInfo {
+							startCursor: String
+							# ...
+						}
+						type MyBook {
+							id: ID
+							name: String
+							missing: Boolean
+						}
+					""";
+			SchemaReport report = inspectSchema(schema, BookController.class);
+			assertThatReport(report).hasUnmappedFieldCount(1).containsUnmappedFields("MyBook", "missing");
+		}
+
 		@Test
 		void reportWorksForQueryWithExtensionType() {
 			String schema = """