immutable arguments (graphql-java#1165)

bbakerman · web-flow · commit 0adc5f8e291c · 2018-08-20T20:15:16.000+10:00
* Added @OverRide as part of errorprone code health check * Revert "Added @OverRide as part of errorprone code health check" This reverts commit 38dfab1 * Immutable arguments * PR feedback on Maps * PR feedback on Maps
diff --git a/src/main/java/graphql/schema/DataFetchingEnvironmentImpl.java b/src/main/java/graphql/schema/DataFetchingEnvironmentImpl.java
@@ -8,12 +8,15 @@
 import graphql.language.Field;
 import graphql.language.FragmentDefinition;
 
+import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
 import static graphql.Assert.assertNotNull;
+import static java.util.Collections.unmodifiableMap;
 
-@SuppressWarnings({"unchecked","TypeParameterUnusedInFormals"})
+@SuppressWarnings({"unchecked", "TypeParameterUnusedInFormals"})
 @Internal
 public class DataFetchingEnvironmentImpl implements DataFetchingEnvironment {
     private final Object source;
@@ -46,15 +49,15 @@ public DataFetchingEnvironmentImpl(Object source,
                                        ExecutionTypeInfo fieldTypeInfo,
                                        ExecutionContext executionContext) {
         this.source = source;
-        this.arguments = arguments;
+        this.arguments = arguments == null ? Collections.emptyMap() : arguments;
+        this.fragmentsByName = fragmentsByName == null ? Collections.emptyMap() : fragmentsByName;
         this.context = context;
         this.root = root;
         this.fieldDefinition = fieldDefinition;
         this.fields = fields;
         this.fieldType = fieldType;
         this.parentType = parentType;
         this.graphQLSchema = graphQLSchema;
-        this.fragmentsByName = fragmentsByName;
         this.executionId = executionId;
         this.selectionSet = selectionSet;
         this.fieldTypeInfo = fieldTypeInfo;
@@ -68,7 +71,7 @@ public <T> T getSource() {
 
     @Override
     public Map<String, Object> getArguments() {
-        return arguments;
+        return new HashMap<>(arguments);
     }
 
     @Override
@@ -123,7 +126,7 @@ public GraphQLSchema getGraphQLSchema() {
 
     @Override
     public Map<String, FragmentDefinition> getFragmentsByName() {
-        return fragmentsByName;
+        return new HashMap<>(fragmentsByName);
     }
 
     @Override
diff --git a/src/test/groovy/graphql/schema/DataFetchingEnvironmentImplTest.groovy b/src/test/groovy/graphql/schema/DataFetchingEnvironmentImplTest.groovy
@@ -0,0 +1,26 @@
+package graphql.schema
+
+import graphql.execution.ExecutionId
+import spock.lang.Specification
+
+import static graphql.execution.ExecutionContextBuilder.*
+import static graphql.schema.DataFetchingEnvironmentBuilder.*
+
+class DataFetchingEnvironmentImplTest extends Specification {
+
+    def executionContext = newExecutionContextBuilder().executionId(ExecutionId.from("123")).build()
+
+    def "immutable arguments"() {
+        def dataFetchingEnvironment = newDataFetchingEnvironment(executionContext).arguments([arg: "argVal"]).build()
+
+        when:
+        def value = dataFetchingEnvironment.getArguments().get("arg")
+        then:
+        value == "argVal"
+        when:
+        dataFetchingEnvironment.getArguments().put("arg", "some other value")
+        value = dataFetchingEnvironment.getArguments().get("arg")
+        then:
+        value == "argVal"
+    }
+}
