Fix regression: if null is passed as parameter to a resolver method, …

src/main/kotlin/graphql/kickstart/tools/resolver/MethodFieldResolver.kt

@@ -80,7 +80,7 @@ internal class MethodFieldResolver(
  return@add Optional.empty<Any>()
  }
 
- if (value != null && shouldValueBeConverted(value, definition, parameterType, environment)) {
+ if (value == null || shouldValueBeConverted(value, definition, parameterType, environment)) {
  return@add mapper.convertValue(value, object : TypeReference<Any>() {
  override fun getType() = parameterType
  })

src/test/kotlin/graphql/kickstart/tools/ResolverMethodsTest.java

@@ -0,0 +1,52 @@
+package graphql.kickstart.tools;
+
+import graphql.ExecutionInput;
+import graphql.ExecutionResult;
+import graphql.GraphQL;
+import graphql.schema.GraphQLSchema;
+import org.junit.Test;
+
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+public class ResolverMethodsTest {
+ // Note: don't convert this code to Kotlin or Groovy, since it's quite important that the
+ // resolver method is defined with an argument of primitive type, like 'boolean', not 'Boolean':
+ // String testOmittedBoolean(boolean value1, Boolean value2)
+ @Test
+ public void testOmittedBooleanArgument() {
+ // In this schema, the 'value1' argument is optional, but the Java resolver defines it as 'boolean'
+ // Instead of failing with an error, we expect the argument to be set to the Java default (i.e. false for booleans)
+ GraphQLSchema schema = SchemaParser.newParser()
+ .schemaString("" +
+ "type Query {" +
+ " testOmittedBoolean(value1: Boolean, value2: Boolean): String" +
+ "}")
+ .resolvers(new Resolver())
+ .build()
+ .makeExecutableSchema();
+
+ GraphQL gql = GraphQL.newGraphQL(schema).build();
+
+ ExecutionResult result = gql
+ .execute(ExecutionInput.newExecutionInput()
+ .query("" +
+ "query { " +
+ " testOmittedBoolean" +
+ "}")
+ .context(new Object())
+ .root(new Object()));
+
+ assertTrue(result.getErrors().isEmpty());
+ assertEquals("false,null", ((Map<?, ?>) result.getData()).get("testOmittedBoolean"));
+ }
+
+ static class Resolver implements GraphQLQueryResolver {
+ @SuppressWarnings("unused")
+ public String testOmittedBoolean(boolean value1, Boolean value2) {
+ return value1 + "," + value2;
+ }
+ }
+}