diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5f021dde0..94e40e39e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,12 @@ You can find and compare releases at the [GitHub release page](https://github.co
 
 ## Unreleased
 
+## v15.15.0
+
+### Added
+
+- Add field config decorator when building schema from SDL https://github.com/webonyx/graphql-php/pull/1590
+
 ## v15.14.3
 
 ### Fixed
diff --git a/src/Utils/ASTDefinitionBuilder.php b/src/Utils/ASTDefinitionBuilder.php
index 96dbb47e6..9d18e801d 100644
--- a/src/Utils/ASTDefinitionBuilder.php
+++ b/src/Utils/ASTDefinitionBuilder.php
@@ -266,7 +266,7 @@ private function internalBuildType(string $typeName, ?Node $typeNode = null): Ty
         if (isset($this->typeDefinitionsMap[$typeName])) {
             $type = $this->makeSchemaDef($this->typeDefinitionsMap[$typeName]);
 
-            if (isset($this->typeConfigDecorator)) {
+            if ($this->typeConfigDecorator !== null) {
                 try {
                     $config = ($this->typeConfigDecorator)(
                         $type->config,
diff --git a/tests/Utils/BuildSchemaTest.php b/tests/Utils/BuildSchemaTest.php
index 508d9369e..8867ec7cd 100644
--- a/tests/Utils/BuildSchemaTest.php
+++ b/tests/Utils/BuildSchemaTest.php
@@ -42,9 +42,7 @@
 use GraphQL\Utils\SchemaPrinter;
 use GraphQL\Validator\Rules\KnownDirectives;
 
-/**
- * @phpstan-import-type UnnamedFieldDefinitionConfig from FieldDefinition
- */
+/** @phpstan-import-type UnnamedFieldDefinitionConfig from FieldDefinition */
 final class BuildSchemaTest extends TestCaseBase
 {
     use ArraySubsetAsserts;
diff --git a/tests/Utils/SchemaExtenderTest.php b/tests/Utils/SchemaExtenderTest.php
index 712328ccb..140924ac3 100644
--- a/tests/Utils/SchemaExtenderTest.php
+++ b/tests/Utils/SchemaExtenderTest.php
@@ -40,9 +40,7 @@
 use GraphQL\Utils\SchemaPrinter;
 use GraphQL\Validator\Rules\KnownDirectives;
 
-/**
- * @phpstan-import-type UnnamedFieldDefinitionConfig from FieldDefinition
- */
+/** @phpstan-import-type UnnamedFieldDefinitionConfig from FieldDefinition */
 final class SchemaExtenderTest extends TestCaseBase
 {
     /** @param NamedType|Schema $obj */