Adding placeholder when there are no queries or no mutations

.travis.yml

@@ -2,6 +2,7 @@ language: php
 php:
 - 7.1
 - 7.2
+- 7.3
 cache:
   directories:
     - $HOME/.composer/cache

src/Annotations/SourceField.php

@@ -105,7 +105,7 @@ public function isLogged(): bool
 
     /**
      * Returns the GraphQL return type of the request (as a string).
-     * The string can represent the FQCN of the type or an entry in the container resolving to the GraphQL type.
+     * The string is the GraphQL output type name.
      *
      * @return string|null
      */

src/Annotations/SourceFieldInterface.php

@@ -30,7 +30,7 @@ public function isLogged(): bool;
 
     /**
      * Returns the GraphQL return type of the request (as a string).
-     * The string can represent the FQCN of the type or an entry in the container resolving to the GraphQL type.
+     * The string is the GraphQL output type name.
      *
      * @return string|null
      */

src/FieldsBuilder.php

@@ -496,7 +496,6 @@ private function mapType(Type $type, ?Type $docBlockType, bool $isNullable, bool
             }
         }
 
-
         return $graphQlType;
     }
 

src/Schema.php

@@ -4,6 +4,7 @@
 namespace TheCodingMachine\GraphQL\Controllers;
 
 use GraphQL\Type\Definition\ObjectType;
+use GraphQL\Type\Definition\Type;
 use GraphQL\Type\SchemaConfig;
 use TheCodingMachine\GraphQL\Controllers\Containers\BasicAutoWiringContainer;
 use TheCodingMachine\GraphQL\Controllers\Mappers\RecursiveTypeMapperInterface;
@@ -26,13 +27,37 @@ public function __construct(QueryProviderInterface $queryProvider, RecursiveType
         $query = new ObjectType([
             'name' => 'Query',
             'fields' => function() use ($queryProvider) {
+                $queries = $queryProvider->getQueries();
+                if (empty($queries)) {
+                    return [
+                        'dummyQuery' => [
+                            'type' => Type::string(),
+                            'description' => 'A placeholder query used by thecodingmachine/graphql-controllers when there are no declared queries.',
+                            'resolve' => function () {
+                                return 'This is a placeholder query. Please create a query using the @Query annotation.';
+                            }
+                        ]
+                    ];
+                }
                 return $queryProvider->getQueries();
             }
         ]);
         $mutation = new ObjectType([
             'name' => 'Mutation',
             'fields' => function() use ($queryProvider) {
-                return $queryProvider->getMutations();
+                $mutations = $queryProvider->getMutations();
+                if (empty($mutations)) {
+                    return [
+                        'dummyMutation' => [
+                            'type' => Type::string(),
+                            'description' => 'A placeholder query used by thecodingmachine/graphql-controllers when there are no declared mutations.',
+                            'resolve' => function () {
+                                return 'This is a placeholder mutation. Please create a mutation using the @Mutation annotation.';
+                            }
+                        ]
+                    ];
+                }
+                return $mutations;
             }
         ]);
 

tests/SchemaTest.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace TheCodingMachine\GraphQL\Controllers;
+
+use PHPUnit\Framework\TestCase;
+
+class SchemaTest extends AbstractQueryProviderTest
+{
+
+    public function testEmptyQuery()
+    {
+        $queryProvider = new class implements QueryProviderInterface {
+            public function getQueries(): array
+            {
+                return [];
+            }
+
+            public function getMutations(): array
+            {
+                return [];
+            }
+        };
+
+        $schema = new Schema($queryProvider, $this->getTypeMapper(), $this->getTypeResolver());
+
+        $fields = $schema->getQueryType()->getFields();
+        $this->assertArrayHasKey('dummyQuery', $fields);
+        $resolve = $fields['dummyQuery']->resolveFn;
+        $this->assertSame('This is a placeholder query. Please create a query using the @Query annotation.', $resolve());
+
+        $fields = $schema->getMutationType()->getFields();
+        $this->assertArrayHasKey('dummyMutation', $fields);
+        $resolve = $fields['dummyMutation']->resolveFn;
+        $this->assertSame('This is a placeholder mutation. Please create a mutation using the @Mutation annotation.', $resolve());
+    }
+}