Make Types throw instead of returning Utils::undefined()

examples/01-blog/Blog/Type/Scalar/UrlType.php

@@ -30,11 +30,12 @@ class UrlType extends ScalarType
      *
      * @param mixed $value
      * @return mixed
+     * @throws Error
      */
     public function parseValue($value)
     {
         if (!is_string($value) || !filter_var($value, FILTER_VALIDATE_URL)) { // quite naive, but after all this is example
-            throw new \UnexpectedValueException("Cannot represent value as URL: " . Utils::printSafe($value));
+            throw new Error("Cannot represent value as URL: " . Utils::printSafe($value));
         }
         return $value;
     }

src/Executor/Executor.php

@@ -1197,8 +1197,7 @@ class Executor
     }
 
     /**
-     * Complete a Scalar or Enum by serializing to a valid value, returning
+     * Complete a Scalar or Enum by serializing to a valid value, throwing if serialization is not possible.
-     * null if serialization is not possible.
      *
      * @param LeafType $returnType
      * @param $result
@@ -1207,14 +1206,21 @@ class Executor
      */
     private function completeLeafValue(LeafType $returnType, &$result)
     {
-        $serializedResult = $returnType->serialize($result);
+        try {
-
+            return $returnType->serialize($result);
-        if (Utils::isInvalid($serializedResult)) {
+        } catch (\Exception $error) {
             throw new InvariantViolation(
-                'Expected a value of type "'. Utils::printSafe($returnType) . '" but received: ' . Utils::printSafe($result)
+                'Expected a value of type "'. Utils::printSafe($returnType) . '" but received: ' . Utils::printSafe($result),
+                0,
+                $error
+            );
+        } catch (\Throwable $error) {
+            throw new InvariantViolation(
+                'Expected a value of type "'. Utils::printSafe($returnType) . '" but received: ' . Utils::printSafe($result),
+                0,
+                $error
             );
         }
-        return $serializedResult;
     }
 
     /**

src/Type/Definition/BooleanType.php

@@ -1,7 +1,9 @@
 <?php
 namespace GraphQL\Type\Definition;
 
+use GraphQL\Error\Error;
 use GraphQL\Language\AST\BooleanValueNode;
+use GraphQL\Language\AST\Node;
 use GraphQL\Utils\Utils;
 
 /**
@@ -32,22 +34,30 @@ class BooleanType extends ScalarType
     /**
      * @param mixed $value
      * @return bool
+     * @throws Error
      */
     public function parseValue($value)
     {
-        return is_bool($value) ? $value : Utils::undefined();
+        if (is_bool($value)) {
+            return $value;
+        }
+
+        throw new Error("Cannot represent value as boolean: " . Utils::printSafe($value));
     }
 
     /**
-     * @param $valueNode
+     * @param Node $valueNode
      * @param array|null $variables
      * @return bool|null
+     * @throws \Exception
      */
     public function parseLiteral($valueNode, array $variables = null)
     {
         if ($valueNode instanceof BooleanValueNode) {
             return (bool) $valueNode->value;
         }
-        return Utils::undefined();
+
+        // Intentionally without message, as all information already in wrapped Exception
+        throw new \Exception();
     }
 }

src/Type/Definition/CustomScalarType.php

@@ -1,6 +1,8 @@
 <?php
 namespace GraphQL\Type\Definition;
 
+use GraphQL\Error\Error;
+use GraphQL\Language\AST\Node;
 use GraphQL\Utils\AST;
 use GraphQL\Utils\Utils;
 
@@ -25,10 +27,6 @@ class CustomScalarType extends ScalarType
      */
     public function parseValue($value)
     {
-        if (Utils::isInvalid($value)) {
-            return Utils::undefined();
-        }
-
         if (isset($this->config['parseValue'])) {
             return call_user_func($this->config['parseValue'], $value);
         } else {
@@ -37,9 +35,10 @@ class CustomScalarType extends ScalarType
     }
 
     /**
-     * @param $valueNode
+     * @param Node $valueNode
      * @param array|null $variables
      * @return mixed
+     * @throws \Exception
      */
     public function parseLiteral(/* GraphQL\Language\AST\ValueNode */ $valueNode, array $variables = null)
     {

src/Type/Definition/EnumType.php

@@ -1,6 +1,7 @@
 <?php
 namespace GraphQL\Type\Definition;
 
+use GraphQL\Error\Error;
 use GraphQL\Error\InvariantViolation;
 use GraphQL\Language\AST\EnumTypeDefinitionNode;
 use GraphQL\Language\AST\EnumValueNode;
@@ -103,7 +104,8 @@ class EnumType extends Type implements InputType, OutputType, LeafType, NamedTyp
 
     /**
      * @param $value
-     * @return null
+     * @return mixed
+     * @throws Error
      */
     public function serialize($value)
     {
@@ -112,36 +114,44 @@ class EnumType extends Type implements InputType, OutputType, LeafType, NamedTyp
             return $lookup[$value]->name;
         }
 
-        return Utils::undefined();
+        throw new Error("Cannot serialize value as enum: " . Utils::printSafe($value));
     }
 
     /**
      * @param $value
-     * @return null
+     * @return mixed
+     * @throws Error
      */
     public function parseValue($value)
     {
         $lookup = $this->getNameLookup();
-        return isset($lookup[$value]) ? $lookup[$value]->value : Utils::undefined();
+        if (isset($lookup[$value])) {
+            return $lookup[$value]->value;
+        }
+
+        throw new Error("Cannot represent value as enum: " . Utils::printSafe($value));
     }
 
     /**
-     * @param $value
+     * @param $valueNode
      * @param array|null $variables
      * @return null
+     * @throws \Exception
      */
-    public function parseLiteral($value, array $variables = null)
+    public function parseLiteral($valueNode, array $variables = null)
     {
-        if ($value instanceof EnumValueNode) {
+        if ($valueNode instanceof EnumValueNode) {
             $lookup = $this->getNameLookup();
-            if (isset($lookup[$value->value])) {
+            if (isset($lookup[$valueNode->value])) {
-                $enumValue = $lookup[$value->value];
+                $enumValue = $lookup[$valueNode->value];
                 if ($enumValue) {
                     return $enumValue->value;
                 }
             }
         }
-        return null;
+
+        // Intentionally without message, as all information already in wrapped Exception
+        throw new \Exception();
     }
 
     /**

src/Type/Definition/FloatType.php

@@ -49,13 +49,16 @@ values as specified by
      * @param $valueNode
      * @param array|null $variables
      * @return float|null
+     * @throws \Exception
      */
     public function parseLiteral($valueNode, array $variables = null)
     {
         if ($valueNode instanceof FloatValueNode || $valueNode instanceof IntValueNode) {
             return (float) $valueNode->value;
         }
-        return Utils::undefined();
+
+        // Intentionally without message, as all information already in wrapped Exception
+        throw new \Exception();
     }
 
     private function coerceFloat($value) {

src/Type/Definition/IDType.php

@@ -3,6 +3,7 @@ namespace GraphQL\Type\Definition;
 
 use GraphQL\Error\Error;
 use GraphQL\Language\AST\IntValueNode;
+use GraphQL\Language\AST\Node;
 use GraphQL\Language\AST\StringValueNode;
 use GraphQL\Utils\Utils;
 
@@ -30,6 +31,7 @@ When expected as an input type, any string (such as `"4"`) or integer
     /**
      * @param mixed $value
      * @return string
+     * @throws Error
      */
     public function serialize($value)
     {
@@ -51,22 +53,30 @@ When expected as an input type, any string (such as `"4"`) or integer
     /**
      * @param mixed $value
      * @return string
+     * @throws Error
      */
     public function parseValue($value)
     {
-        return (is_string($value) || is_int($value)) ? (string) $value : Utils::undefined();
+        if (is_string($value) || is_int($value)) {
+            return (string) $value;
+        }
+
+        throw new Error("Cannot represent value as ID: " . Utils::printSafe($value));
     }
 
     /**
-     * @param $ast
+     * @param Node $valueNode
      * @param array|null $variables
      * @return null|string
+     * @throws \Exception
      */
     public function parseLiteral($valueNode, array $variables = null)
     {
         if ($valueNode instanceof StringValueNode || $valueNode instanceof IntValueNode) {
             return $valueNode->value;
         }
-        return Utils::undefined();
+
+        // Intentionally without message, as all information already in wrapped Exception
+        throw new \Exception();
     }
 }

src/Type/Definition/IntType.php

@@ -55,6 +55,7 @@ values. Int can represent values between -(2^31) and 2^31 - 1. ';
      * @param $valueNode
      * @param array|null $variables
      * @return int|null
+     * @throws \Exception
      */
     public function parseLiteral($valueNode, array $variables = null)
     {
@@ -64,7 +65,9 @@ values. Int can represent values between -(2^31) and 2^31 - 1. ';
                 return $val;
             }
         }
-        return Utils::undefined();
+
+        // Intentionally without message, as all information already in wrapped Exception
+        throw new \Exception();
     }
 
     private function coerceInt($value) {

src/Type/Definition/LeafType.php

@@ -1,6 +1,7 @@
 <?php
 namespace GraphQL\Type\Definition;
 
+use GraphQL\Error\Error;
 use \GraphQL\Language\AST\Node;
 
 /*
@@ -15,27 +16,30 @@ interface LeafType
      *
      * @param mixed $value
      * @return mixed
+     * @throws Error
      */
     public function serialize($value);
 
     /**
      * Parses an externally provided value (query variable) to use as an input
      *
-     * In the case of an invalid value this method must return Utils::undefined()
+     * In the case of an invalid value this method must throw an Exception
      *
      * @param mixed $value
      * @return mixed
+     * @throws Error
      */
     public function parseValue($value);
 
     /**
      * Parses an externally provided literal value (hardcoded in GraphQL query) to use as an input
      *
-     * In the case of an invalid value this method must return Utils::undefined()
+     * In the case of an invalid node or value this method must throw an Exception
      *
      * @param Node $valueNode
      * @param array|null $variables
      * @return mixed
+     * @throws \Exception
      */
     public function parseLiteral($valueNode, array $variables = null);
 }

src/Type/Definition/StringType.php

@@ -60,13 +60,16 @@ represent free-form human-readable text.';
      * @param $valueNode
      * @param array|null $variables
      * @return null|string
+     * @throws \Exception
      */
     public function parseLiteral($valueNode, array $variables = null)
     {
         if ($valueNode instanceof StringValueNode) {
             return $valueNode->value;
         }
-        return Utils::undefined();
+
+        // Intentionally without message, as all information already in wrapped Exception
+        throw new \Exception();
     }
 
     private function coerceString($value) {

src/Utils/AST.php

@@ -209,10 +209,19 @@ class AST
         if ($type instanceof ScalarType || $type instanceof EnumType) {
             // Since value is an internally represented value, it must be serialized
             // to an externally represented value before converting into an AST.
+            try {
                 $serialized = $type->serialize($value);
-            if (null === $serialized || Utils::isInvalid($serialized)) {
+            } catch (\Exception $error) {
+                if ($error instanceof Error && $type instanceof EnumType) {
                     return null;
                 }
+                throw $error;
+            } catch (\Throwable $error) {
+                if ($error instanceof Error && $type instanceof EnumType) {
+                    return null;
+                }
+                throw $error;
+            }
 
             // Others serialize based on their corresponding PHP scalar types.
             if (is_bool($serialized)) {
@@ -400,18 +409,12 @@ class AST
             // Invalid values represent a failure to parse correctly, in which case
             // no value is returned.
             try {
-                $result = $type->parseLiteral($valueNode, $variables);
+                return $type->parseLiteral($valueNode, $variables);
             } catch (\Exception $error) {
                 return $undefined;
             } catch (\Throwable $error) {
                 return $undefined;
             }
-
-            if (Utils::isInvalid($result)) {
-                return $undefined;
-            }
-
-            return $result;
         }
 
         throw new Error('Unknown type: ' . Utils::printSafe($type) . '.');
@@ -420,7 +423,7 @@ class AST
     /**
      * Produces a PHP value given a GraphQL Value AST.
      *
-     * Unlike `valueFromAST()`, no type is provided. The resulting JavaScript value
+     * Unlike `valueFromAST()`, no type is provided. The resulting PHP value
      * will reflect the provided GraphQL value AST.
      *
      * | GraphQL Value        | PHP Value     |
@@ -471,7 +474,7 @@ class AST
               );
             case $valueNode instanceof VariableNode:
                 $variableName = $valueNode->name->value;
-                return ($variables && isset($variables[$variableName]) && !Utils::isInvalid($variables[$variableName]))
+                return ($variables && isset($variables[$variableName]))
                     ? $variables[$variableName]
                     : null;
         }

src/Utils/Value.php

@@ -46,14 +46,7 @@ class Value
             // throw to indicate failure. If it throws, maintain a reference to
             // the original error.
             try {
-                $parseResult = $type->parseValue($value);
+                return self::ofValue($type->parseValue($value));
-                if (Utils::isInvalid($parseResult)) {
-                    return self::ofErrors([
-                        self::coercionError("Expected type {$type->name}", $blameNode, $path),
-                    ]);
-                }
-
-                return self::ofValue($parseResult);
             } catch (\Exception $error) {
                 return self::ofErrors([
                     self::coercionError(

src/Validator/Rules/ValuesOfCorrectType.php

@@ -173,20 +173,9 @@ class ValuesOfCorrectType extends AbstractValidationRule
         }
 
         // Scalars determine if a literal value is valid via parseLiteral() which
-        // may throw or return an invalid value to indicate failure.
+        // may throw to indicate failure.
         try {
-            $parseResult = $type->parseLiteral($node);
+            $type->parseLiteral($node);
-            if (Utils::isInvalid($parseResult)) {
-                $context->reportError(
-                    new Error(
-                        self::badValueMessage(
-                            (string) $locationType,
-                            Printer::doPrint($node)
-                        ),
-                        $node
-                    )
-                );
-            }
         } catch (\Exception $error) {
             // Ensure a reference to the original error is maintained.
             $context->reportError(

tests/Executor/TestClasses.php

@@ -1,6 +1,7 @@
 <?php
 namespace GraphQL\Tests\Executor;
 
+use GraphQL\Error\Error;
 use GraphQL\Type\Definition\ScalarType;
 use GraphQL\Utils\Utils;
 
@@ -53,28 +54,40 @@ class ComplexScalar extends ScalarType
 
     public $name = 'ComplexScalar';
 
+    /**
+     * {@inheritdoc}
+     */
     public function serialize($value)
     {
         if ($value === 'DeserializedValue') {
             return 'SerializedValue';
         }
-        return null;
+
+        throw new Error("Cannot serialize value as ComplexScalar: " . Utils::printSafe($value));
     }
 
+    /**
+     * {@inheritdoc}
+     */
     public function parseValue($value)
     {
         if ($value === 'SerializedValue') {
             return 'DeserializedValue';
         }
-        return Utils::undefined();
+
+        throw new Error("Cannot represent value as ComplexScalar: " . Utils::printSafe($value));
     }
 
+    /**
+     * {@inheritdoc}
+     */
     public function parseLiteral($valueNode, array $variables = null)
     {
         if ($valueNode->value === 'SerializedValue') {
             return 'DeserializedValue';
         }
-        return Utils::undefined();
+
+        throw new Error("Cannot represent literal as ComplexScalar: " . Utils::printSafe($valueNode->value));
     }
 }