Convert annotated type array into single type + nullable for 3.0 (#1786)

Author: DerManoMann

src/Annotations/AbstractAnnotation.php

@@ -381,10 +381,21 @@ public function jsonSerialize()
                 $data->minimum = $data->exclusiveMinimum;
                 $data->exclusiveMinimum = true;
             }
+
             if (isset($data->exclusiveMaximum) && is_numeric($data->exclusiveMaximum)) {
                 $data->maximum = $data->exclusiveMaximum;
                 $data->exclusiveMaximum = true;
             }
+
+            if (isset($data->type) && is_array($data->type)) {
+                if (in_array('null', $data->type)) {
+                    $data->nullable = true;
+                    $data->type = array_filter($data->type, fn ($v): bool => $v !== 'null');
+                    if (1 === count($data->type)) {
+                        $data->type = array_pop($data->type);
+                    }
+                }
+            }
         }
 
         if ($this->_context->isVersion(OpenApi::VERSION_3_1_0)) {

tests/Fixtures/Scratch/Nullable3.0.0.yaml

@@ -46,9 +46,8 @@ components:
               $ref: '#/components/schemas/MyDateTime'
           nullable: true
         description:
-          type:
-            - string
-            - 'null'
+          type: string
+          nullable: true
         choice:
           type: string
           enum: