Merge branch '1.4.x'

Author: bclozel

spring-graphql/src/main/java/org/springframework/graphql/data/pagination/ConnectionFieldTypeVisitor.java

@@ -24,6 +24,7 @@
 
 import graphql.TrivialDataFetcher;
 import graphql.execution.DataFetcherResult;
+import graphql.language.NonNullType;
 import graphql.relay.Connection;
 import graphql.relay.DefaultConnection;
 import graphql.relay.DefaultConnectionCursor;
@@ -50,6 +51,7 @@
 import reactor.core.publisher.Mono;
 
 import org.springframework.graphql.execution.TypeVisitorHelper;
+import org.springframework.lang.Contract;
 import org.springframework.util.Assert;
 
 /**
@@ -101,7 +103,7 @@ public TraversalControl visitGraphQLFieldDefinition(
 				}
 			}
 			else {
-				dataFetcher = new ConnectionDataFetcher(dataFetcher, this.adapter);
+				dataFetcher = new ConnectionDataFetcher(dataFetcher, this.adapter, fieldDefinition);
 				codeRegistry.dataFetcher(fieldCoordinates, dataFetcher);
 			}
 		}
@@ -186,10 +188,11 @@ public static ConnectionFieldTypeVisitor create(List<ConnectionAdapter> adapters
 
 	/**
 	 * {@code DataFetcher} decorator that adapts return values with an adapter.
-	 * @param delegate the datafetcher delegate
+	 * @param delegate the DataFetcher delegate
 	 * @param adapter the connection adapter to use
+	 * @param connectionFieldDefinition the field definition for the connection type
 	 */
-	record ConnectionDataFetcher(DataFetcher<?> delegate, ConnectionAdapter adapter) implements DataFetcher<Object> {
+	record ConnectionDataFetcher(DataFetcher<?> delegate, ConnectionAdapter adapter, GraphQLFieldDefinition connectionFieldDefinition) implements DataFetcher<Object> {
 
 		private static final Connection<?> EMPTY_CONNECTION =
 				new DefaultConnection<>(Collections.emptyList(), new DefaultPageInfo(null, null, false, false));
@@ -198,11 +201,12 @@ record ConnectionDataFetcher(DataFetcher<?> delegate, ConnectionAdapter adapter)
 		ConnectionDataFetcher {
 			Assert.notNull(delegate, "DataFetcher delegate is required");
 			Assert.notNull(adapter, "ConnectionAdapter is required");
+			Assert.notNull(connectionFieldDefinition, "GraphQLFieldDefinition is required");
 		}
 
 
 		@Override
-		public Object get(DataFetchingEnvironment environment) throws Exception {
+		public @Nullable Object get(DataFetchingEnvironment environment) throws Exception {
 			Object result = this.delegate.get(environment);
 			if (result instanceof Mono<?> mono) {
 				return mono.map(this::adaptDataFetcherResult);
@@ -215,7 +219,8 @@ else if (result instanceof CompletionStage<?> stage) {
 			}
 		}
 
-		private Object adaptDataFetcherResult(@Nullable Object value) {
+		@Contract("!null -> !null")
+		private @Nullable Object adaptDataFetcherResult(@Nullable Object value) {
 			if (value instanceof DataFetcherResult<?> dataFetcherResult) {
 				Object adapted = adaptDataContainer(dataFetcherResult.getData());
 				return DataFetcherResult.newResult()
@@ -228,9 +233,9 @@ private Object adaptDataFetcherResult(@Nullable Object value) {
 			}
 		}
 
-		private <T> Object adaptDataContainer(@Nullable Object container) {
+		private <T> @Nullable Object adaptDataContainer(@Nullable Object container) {
 			if (container == null) {
-				return EMPTY_CONNECTION;
+				return isConnectionTypeNullable() ? null : EMPTY_CONNECTION;
 			}
 
 			if (container instanceof Connection<?>) {
@@ -264,6 +269,13 @@ private <T> Object adaptDataContainer(@Nullable Object container) {
 			return new DefaultConnection<>(edges, pageInfo);
 		}
 
+		private boolean isConnectionTypeNullable() {
+			if (this.connectionFieldDefinition.getDefinition() != null) {
+				return !(this.connectionFieldDefinition.getDefinition().getType() instanceof NonNullType);
+			}
+			return true;
+		}
+
 	}
 
 }

spring-graphql/src/main/java/org/springframework/graphql/data/query/PropertySelection.java

@@ -24,6 +24,8 @@
 
 import graphql.schema.DataFetchingFieldSelectionSet;
 import graphql.schema.GraphQLNamedOutputType;
+import graphql.schema.GraphQLNonNull;
+import graphql.schema.GraphQLType;
 import graphql.schema.SelectedField;
 
 import org.springframework.data.mapping.PropertyPath;
@@ -108,9 +110,16 @@ else if (isConnectionEdgeNode(selectedField)) {
 	}
 
 	private static boolean isConnectionEdges(SelectedField selectedField) {
-		return selectedField.getName().equals("edges") &&
-				selectedField.getParentField().getType() instanceof GraphQLNamedOutputType namedType &&
-				namedType.getName().endsWith("Connection");
+		if (selectedField.getName().equals("edges")) {
+			GraphQLType fieldType = selectedField.getParentField().getType();
+			if (fieldType instanceof GraphQLNonNull nonNullType) {
+				fieldType = nonNullType.getWrappedType();
+			}
+			if (fieldType instanceof GraphQLNamedOutputType namedType) {
+				return namedType.getName().endsWith("Connection");
+			}
+		}
+		return false;
 	}
 
 	private static boolean isConnectionEdgeNode(SelectedField selectedField) {

spring-graphql/src/test/java/org/springframework/graphql/data/pagination/ConnectionFieldTypeVisitorTests.java

@@ -137,15 +137,35 @@ void customConnectionTypeIsPassedThrough() {
 		);
 	}
 
-	@Test // gh-707
-	void nullValueTreatedAsEmptyConnection() {
+	@Test // gh-707, gh-1295
+	void nullValueTreatedAsNullConnectionWhenNullable() {
 
 		Mono<ExecutionGraphQlResponse> response = GraphQlSetup.schemaResource(BookSource.paginationSchema)
 				.dataFetcher("Query", "books", environment -> null)
 				.connectionSupport(new ListConnectionAdapter())
 				.toGraphQlService()
 				.execute(BookSource.booksConnectionQuery(null));
 
+		ResponseHelper.forResponse(response).assertData("{\"books\":null}");
+	}
+
+	@Test // gh-1295
+	void nullValueTreatedAsEmptyConnectionWhenNonNullable() {
+		Mono<ExecutionGraphQlResponse> response = GraphQlSetup.schemaContent("""
+						type Query {
+							books(first:Int, after:String): BookConnection!
+						}
+
+						type Book {
+							id: ID
+							name: String
+						}
+						""")
+				.dataFetcher("Query", "books", environment -> null)
+				.connectionSupport(new ListConnectionAdapter())
+				.toGraphQlService()
+				.execute(BookSource.booksConnectionQuery(null));
+
 		ResponseHelper.forResponse(response).assertData(
 				"{\"books\":{" +
 						"\"edges\":[]," +

spring-graphql/src/test/java/org/springframework/graphql/data/query/PropertySelectionTests.java

@@ -16,13 +16,19 @@
 
 package org.springframework.graphql.data.query;
 
+import java.nio.charset.StandardCharsets;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicReference;
+import java.util.stream.Stream;
 
 import graphql.schema.DataFetcher;
 import graphql.schema.DataFetchingFieldSelectionSet;
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
+import org.springframework.core.io.ByteArrayResource;
+import org.springframework.core.io.Resource;
 import org.springframework.data.util.TypeInformation;
 import org.springframework.graphql.BookSource;
 import org.springframework.graphql.GraphQlSetup;
@@ -34,19 +40,21 @@
  * Unit test for {@link PropertySelection}.
  *
  * @author Rossen Stoyanchev
+ * @author Brian Clozel
  */
 class PropertySelectionTests {
 
-	@Test
-	void propertySelectionWithConnection() {
+	@ParameterizedTest
+	@MethodSource("schemaResource")
+	void propertySelectionWithConnection(Resource schemaResource) {
 
 		AtomicReference<DataFetchingFieldSelectionSet> ref = new AtomicReference<>();
 		DataFetcher<?> dataFetcher = environment -> {
 			ref.set(environment.getSelectionSet());
 			return null;
 		};
 
-		GraphQlSetup.schemaResource(BookSource.paginationSchema)
+		GraphQlSetup.schemaResource(schemaResource)
 				.typeDefinitionConfigurer(new ConnectionTypeDefinitionConfigurer())
 				.dataFetcher("Query", "books", dataFetcher)
 				.toGraphQlService()
@@ -59,4 +67,20 @@ void propertySelectionWithConnection() {
 		assertThat(list).containsExactly("id", "name");
 	}
 
+	static Stream<Arguments> schemaResource() {
+		return Stream.of(
+				Arguments.of(BookSource.paginationSchema),
+				Arguments.of(new ByteArrayResource("""
+						type Query {
+							books(first:Int, after:String): BookConnection!
+						}
+
+						type Book {
+							id: ID
+							name: String
+						}
+						""".getBytes(StandardCharsets.UTF_8)))
+		);
+	}
+
 }