diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
index 877e5dabfa7..218b5c1f1da 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
@@ -3929,6 +3929,11 @@ public class DefaultCodegen implements CodegenConfig {
         List<CodegenParameter> parameters = new ArrayList<CodegenParameter>();
         LOGGER.debug("debugging fromRequestBodyToFormParameters= " + body);
         Schema schema = getSchemaFromBody(body);
+        if (StringUtils.isNotBlank(schema.get$ref())) {
+            schema = schemas.get(
+                    getSimpleRef(schema.get$ref())
+            );
+        }
         if (schema.getProperties() != null && !schema.getProperties().isEmpty()) {
             Map<String, Schema> properties = schema.getProperties();
             for (Map.Entry<String, Schema> entry : properties.entrySet()) {
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/FakeApi.md b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/FakeApi.md
index f68855dfd30..9f79de03403 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/FakeApi.md
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/FakeApi.md
@@ -261,7 +261,7 @@ No authorization required
 [[Back to top]](#) [[Back to API list]](../../README.md#documentation-for-api-endpoints) [[Back to Model list]](../../README.md#documentation-for-models) [[Back to README]](../../README.md)
 
 # **testEndpointParameters**
-> testEndpointParameters()
+> testEndpointParameters($integer, $int32, $int64, $number, $float, $double, $string, $pattern_without_delimiter, $byte, $binary, $date, $date_time, $password, $callback)
 
 Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트
 
@@ -284,9 +284,23 @@ $apiInstance = new Swagger\Client\Api\FakeApi(
     new GuzzleHttp\Client(),
     $config
 );
+$integer = 56; // int | None
+$int32 = 56; // int | None
+$int64 = 56; // int | None
+$number = new \Swagger\Client\Model\BigDecimal(); // BigDecimal | None
+$float = 3.4; // float | None
+$double = 3.4; // double | None
+$string = "string_example"; // string | None
+$pattern_without_delimiter = "pattern_without_delimiter_example"; // string | None
+$byte = "byte_example"; // string | None
+$binary = "binary_example"; // string | None
+$date = "date_example"; // \DateTime | None
+$date_time = "date_time_example"; // \DateTime | None
+$password = "password_example"; // string | None
+$callback = "callback_example"; // string | None
 
 try {
-    $apiInstance->testEndpointParameters();
+    $apiInstance->testEndpointParameters($integer, $int32, $int64, $number, $float, $double, $string, $pattern_without_delimiter, $byte, $binary, $date, $date_time, $password, $callback);
 } catch (Exception $e) {
     echo 'Exception when calling FakeApi->testEndpointParameters: ', $e->getMessage(), PHP_EOL;
 }
@@ -294,7 +308,23 @@ try {
 ```
 
 ### Parameters
-This endpoint does not need any parameter.
+
+Name | Type | Description  | Notes
+------------- | ------------- | ------------- | -------------
+ **integer** | **int**| None | [optional]
+ **int32** | **int**| None | [optional]
+ **int64** | **int**| None | [optional]
+ **number** | **BigDecimal**| None | [optional]
+ **float** | **float**| None | [optional]
+ **double** | **double**| None | [optional]
+ **string** | **string**| None | [optional]
+ **pattern_without_delimiter** | **string**| None | [optional]
+ **byte** | **string**| None | [optional]
+ **binary** | **string**| None | [optional]
+ **date** | **\DateTime**| None | [optional]
+ **date_time** | **\DateTime**| None | [optional]
+ **password** | **string**| None | [optional]
+ **callback** | **string**| None | [optional]
 
 ### Return type
 
@@ -312,7 +342,7 @@ void (empty response body)
 [[Back to top]](#) [[Back to API list]](../../README.md#documentation-for-api-endpoints) [[Back to Model list]](../../README.md#documentation-for-models) [[Back to README]](../../README.md)
 
 # **testEnumParameters**
-> testEnumParameters($enum_header_string_array, $enum_header_string, $enum_query_string_array, $enum_query_string, $enum_query_integer)
+> testEnumParameters($enum_header_string_array, $enum_header_string, $enum_query_string_array, $enum_query_string, $enum_query_integer, $enum_form_string_array, $enum_form_string, $enum_query_double)
 
 To test enum parameters
 
@@ -333,9 +363,12 @@ $enum_header_string = "enum_header_string_example"; // string | Header parameter
 $enum_query_string_array = array("enum_query_string_array_example"); // string[] | Query parameter enum test (string array)
 $enum_query_string = "enum_query_string_example"; // string | Query parameter enum test (string)
 $enum_query_integer = 56; // int | Query parameter enum test (double)
+$enum_form_string_array = new \Swagger\Client\Model\array(); // string[] | Form parameter enum test (string array)
+$enum_form_string = "enum_form_string_example"; // string | Form parameter enum test (string)
+$enum_query_double = 3.4; // double | Query parameter enum test (double)
 
 try {
-    $apiInstance->testEnumParameters($enum_header_string_array, $enum_header_string, $enum_query_string_array, $enum_query_string, $enum_query_integer);
+    $apiInstance->testEnumParameters($enum_header_string_array, $enum_header_string, $enum_query_string_array, $enum_query_string, $enum_query_integer, $enum_form_string_array, $enum_form_string, $enum_query_double);
 } catch (Exception $e) {
     echo 'Exception when calling FakeApi->testEnumParameters: ', $e->getMessage(), PHP_EOL;
 }
@@ -351,6 +384,9 @@ Name | Type | Description  | Notes
  **enum_query_string_array** | [**string[]**](../Model/string.md)| Query parameter enum test (string array) | [optional]
  **enum_query_string** | **string**| Query parameter enum test (string) | [optional]
  **enum_query_integer** | **int**| Query parameter enum test (double) | [optional]
+ **enum_form_string_array** | [**string[]**](../Model/array.md)| Form parameter enum test (string array) | [optional]
+ **enum_form_string** | **string**| Form parameter enum test (string) | [optional]
+ **enum_query_double** | **double**| Query parameter enum test (double) | [optional]
 
 ### Return type
 
@@ -414,7 +450,7 @@ No authorization required
 [[Back to top]](#) [[Back to API list]](../../README.md#documentation-for-api-endpoints) [[Back to Model list]](../../README.md#documentation-for-models) [[Back to README]](../../README.md)
 
 # **testJsonFormData**
-> testJsonFormData()
+> testJsonFormData($param, $param2)
 
 test json serialization of form data
 
@@ -428,9 +464,11 @@ $apiInstance = new Swagger\Client\Api\FakeApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
+$param = "param_example"; // string | field1
+$param2 = "param2_example"; // string | field2
 
 try {
-    $apiInstance->testJsonFormData();
+    $apiInstance->testJsonFormData($param, $param2);
 } catch (Exception $e) {
     echo 'Exception when calling FakeApi->testJsonFormData: ', $e->getMessage(), PHP_EOL;
 }
@@ -438,7 +476,11 @@ try {
 ```
 
 ### Parameters
-This endpoint does not need any parameter.
+
+Name | Type | Description  | Notes
+------------- | ------------- | ------------- | -------------
+ **param** | **string**| field1 | [optional]
+ **param2** | **string**| field2 | [optional]
 
 ### Return type
 
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/PetApi.md b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/PetApi.md
index d4fac6cf75b..dc6a9fb94e1 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/PetApi.md
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/PetApi.md
@@ -328,7 +328,7 @@ void (empty response body)
 [[Back to top]](#) [[Back to API list]](../../README.md#documentation-for-api-endpoints) [[Back to Model list]](../../README.md#documentation-for-models) [[Back to README]](../../README.md)
 
 # **updatePetWithForm**
-> updatePetWithForm($pet_id)
+> updatePetWithForm($pet_id, $name, $status)
 
 Updates a pet in the store with form data
 
@@ -347,9 +347,11 @@ $apiInstance = new Swagger\Client\Api\PetApi(
     $config
 );
 $pet_id = 789; // int | ID of pet that needs to be updated
+$name = "name_example"; // string | Updated name of the pet
+$status = "status_example"; // string | Updated status of the pet
 
 try {
-    $apiInstance->updatePetWithForm($pet_id);
+    $apiInstance->updatePetWithForm($pet_id, $name, $status);
 } catch (Exception $e) {
     echo 'Exception when calling PetApi->updatePetWithForm: ', $e->getMessage(), PHP_EOL;
 }
@@ -361,6 +363,8 @@ try {
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
  **pet_id** | **int**| ID of pet that needs to be updated |
+ **name** | **string**| Updated name of the pet | [optional]
+ **status** | **string**| Updated status of the pet | [optional]
 
 ### Return type
 
@@ -378,7 +382,7 @@ void (empty response body)
 [[Back to top]](#) [[Back to API list]](../../README.md#documentation-for-api-endpoints) [[Back to Model list]](../../README.md#documentation-for-models) [[Back to README]](../../README.md)
 
 # **uploadFile**
-> \Swagger\Client\Model\ApiResponse uploadFile($pet_id)
+> \Swagger\Client\Model\ApiResponse uploadFile($pet_id, $additional_metadata, $file)
 
 uploads an image
 
@@ -397,9 +401,11 @@ $apiInstance = new Swagger\Client\Api\PetApi(
     $config
 );
 $pet_id = 789; // int | ID of pet to update
+$additional_metadata = "additional_metadata_example"; // string | Additional data to pass to server
+$file = "file_example"; // string | file to upload
 
 try {
-    $result = $apiInstance->uploadFile($pet_id);
+    $result = $apiInstance->uploadFile($pet_id, $additional_metadata, $file);
     print_r($result);
 } catch (Exception $e) {
     echo 'Exception when calling PetApi->uploadFile: ', $e->getMessage(), PHP_EOL;
@@ -412,6 +418,8 @@ try {
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
  **pet_id** | **int**| ID of pet to update |
+ **additional_metadata** | **string**| Additional data to pass to server | [optional]
+ **file** | **string**| file to upload | [optional]
 
 ### Return type
 
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/FakeApi.php b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/FakeApi.php
index 0db5bde5f4b..0ffa7def36f 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/FakeApi.php
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/FakeApi.php
@@ -1337,14 +1337,28 @@ class FakeApi
      *
      * Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트
      *
+     * @param  int $integer None (optional)
+     * @param  int $int32 None (optional)
+     * @param  int $int64 None (optional)
+     * @param  BigDecimal $number None (optional)
+     * @param  float $float None (optional)
+     * @param  double $double None (optional)
+     * @param  string $string None (optional)
+     * @param  string $pattern_without_delimiter None (optional)
+     * @param  string $byte None (optional)
+     * @param  string $binary None (optional)
+     * @param  \DateTime $date None (optional)
+     * @param  \DateTime $date_time None (optional)
+     * @param  string $password None (optional)
+     * @param  string $callback None (optional)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
      * @return void
      */
-    public function testEndpointParameters()
+    public function testEndpointParameters($integer = null, $int32 = null, $int64 = null, $number = null, $float = null, $double = null, $string = null, $pattern_without_delimiter = null, $byte = null, $binary = null, $date = null, $date_time = null, $password = null, $callback = null)
     {
-        $this->testEndpointParametersWithHttpInfo();
+        $this->testEndpointParametersWithHttpInfo($integer, $int32, $int64, $number, $float, $double, $string, $pattern_without_delimiter, $byte, $binary, $date, $date_time, $password, $callback);
     }
 
     /**
@@ -1352,15 +1366,29 @@ class FakeApi
      *
      * Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트
      *
+     * @param  int $integer None (optional)
+     * @param  int $int32 None (optional)
+     * @param  int $int64 None (optional)
+     * @param  BigDecimal $number None (optional)
+     * @param  float $float None (optional)
+     * @param  double $double None (optional)
+     * @param  string $string None (optional)
+     * @param  string $pattern_without_delimiter None (optional)
+     * @param  string $byte None (optional)
+     * @param  string $binary None (optional)
+     * @param  \DateTime $date None (optional)
+     * @param  \DateTime $date_time None (optional)
+     * @param  string $password None (optional)
+     * @param  string $callback None (optional)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
      * @return array of null, HTTP status code, HTTP response headers (array of strings)
      */
-    public function testEndpointParametersWithHttpInfo()
+    public function testEndpointParametersWithHttpInfo($integer = null, $int32 = null, $int64 = null, $number = null, $float = null, $double = null, $string = null, $pattern_without_delimiter = null, $byte = null, $binary = null, $date = null, $date_time = null, $password = null, $callback = null)
     {
         $returnType = '';
-        $request = $this->testEndpointParametersRequest();
+        $request = $this->testEndpointParametersRequest($integer, $int32, $int64, $number, $float, $double, $string, $pattern_without_delimiter, $byte, $binary, $date, $date_time, $password, $callback);
 
         try {
             $options = $this->createHttpClientOption();
@@ -1404,13 +1432,27 @@ class FakeApi
      *
      * Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트
      *
+     * @param  int $integer None (optional)
+     * @param  int $int32 None (optional)
+     * @param  int $int64 None (optional)
+     * @param  BigDecimal $number None (optional)
+     * @param  float $float None (optional)
+     * @param  double $double None (optional)
+     * @param  string $string None (optional)
+     * @param  string $pattern_without_delimiter None (optional)
+     * @param  string $byte None (optional)
+     * @param  string $binary None (optional)
+     * @param  \DateTime $date None (optional)
+     * @param  \DateTime $date_time None (optional)
+     * @param  string $password None (optional)
+     * @param  string $callback None (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function testEndpointParametersAsync()
+    public function testEndpointParametersAsync($integer = null, $int32 = null, $int64 = null, $number = null, $float = null, $double = null, $string = null, $pattern_without_delimiter = null, $byte = null, $binary = null, $date = null, $date_time = null, $password = null, $callback = null)
     {
-        return $this->testEndpointParametersAsyncWithHttpInfo()
+        return $this->testEndpointParametersAsyncWithHttpInfo($integer, $int32, $int64, $number, $float, $double, $string, $pattern_without_delimiter, $byte, $binary, $date, $date_time, $password, $callback)
             ->then(
                 function ($response) {
                     return $response[0];
@@ -1423,14 +1465,28 @@ class FakeApi
      *
      * Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트
      *
+     * @param  int $integer None (optional)
+     * @param  int $int32 None (optional)
+     * @param  int $int64 None (optional)
+     * @param  BigDecimal $number None (optional)
+     * @param  float $float None (optional)
+     * @param  double $double None (optional)
+     * @param  string $string None (optional)
+     * @param  string $pattern_without_delimiter None (optional)
+     * @param  string $byte None (optional)
+     * @param  string $binary None (optional)
+     * @param  \DateTime $date None (optional)
+     * @param  \DateTime $date_time None (optional)
+     * @param  string $password None (optional)
+     * @param  string $callback None (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function testEndpointParametersAsyncWithHttpInfo()
+    public function testEndpointParametersAsyncWithHttpInfo($integer = null, $int32 = null, $int64 = null, $number = null, $float = null, $double = null, $string = null, $pattern_without_delimiter = null, $byte = null, $binary = null, $date = null, $date_time = null, $password = null, $callback = null)
     {
         $returnType = '';
-        $request = $this->testEndpointParametersRequest();
+        $request = $this->testEndpointParametersRequest($integer, $int32, $int64, $number, $float, $double, $string, $pattern_without_delimiter, $byte, $binary, $date, $date_time, $password, $callback);
 
         return $this->client
             ->sendAsync($request, $this->createHttpClientOption())
@@ -1458,12 +1514,65 @@ class FakeApi
     /**
      * Create request for operation 'testEndpointParameters'
      *
+     * @param  int $integer None (optional)
+     * @param  int $int32 None (optional)
+     * @param  int $int64 None (optional)
+     * @param  BigDecimal $number None (optional)
+     * @param  float $float None (optional)
+     * @param  double $double None (optional)
+     * @param  string $string None (optional)
+     * @param  string $pattern_without_delimiter None (optional)
+     * @param  string $byte None (optional)
+     * @param  string $binary None (optional)
+     * @param  \DateTime $date None (optional)
+     * @param  \DateTime $date_time None (optional)
+     * @param  string $password None (optional)
+     * @param  string $callback None (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
      */
-    protected function testEndpointParametersRequest()
+    protected function testEndpointParametersRequest($integer = null, $int32 = null, $int64 = null, $number = null, $float = null, $double = null, $string = null, $pattern_without_delimiter = null, $byte = null, $binary = null, $date = null, $date_time = null, $password = null, $callback = null)
     {
+        if ($integer !== null && $integer > 100) {
+            throw new \InvalidArgumentException('invalid value for "$integer" when calling FakeApi.testEndpointParameters, must be smaller than or equal to 100.');
+        }
+        if ($integer !== null && $integer < 10) {
+            throw new \InvalidArgumentException('invalid value for "$integer" when calling FakeApi.testEndpointParameters, must be bigger than or equal to 10.');
+        }
+
+        if ($int32 !== null && $int32 > 200) {
+            throw new \InvalidArgumentException('invalid value for "$int32" when calling FakeApi.testEndpointParameters, must be smaller than or equal to 200.');
+        }
+        if ($int32 !== null && $int32 < 20) {
+            throw new \InvalidArgumentException('invalid value for "$int32" when calling FakeApi.testEndpointParameters, must be bigger than or equal to 20.');
+        }
+
+        if ($number !== null && $number > 543.2) {
+            throw new \InvalidArgumentException('invalid value for "$number" when calling FakeApi.testEndpointParameters, must be smaller than or equal to 543.2.');
+        }
+        if ($number !== null && $number < 32.1) {
+            throw new \InvalidArgumentException('invalid value for "$number" when calling FakeApi.testEndpointParameters, must be bigger than or equal to 32.1.');
+        }
+
+        if ($float !== null && $float > 987.6) {
+            throw new \InvalidArgumentException('invalid value for "$float" when calling FakeApi.testEndpointParameters, must be smaller than or equal to 987.6.');
+        }
+
+        if ($double !== null && $double > 123.4) {
+            throw new \InvalidArgumentException('invalid value for "$double" when calling FakeApi.testEndpointParameters, must be smaller than or equal to 123.4.');
+        }
+        if ($double !== null && $double < 67.8) {
+            throw new \InvalidArgumentException('invalid value for "$double" when calling FakeApi.testEndpointParameters, must be bigger than or equal to 67.8.');
+        }
+
+        if ($password !== null && strlen($password) > 64) {
+            throw new \InvalidArgumentException('invalid length for "$password" when calling FakeApi.testEndpointParameters, must be smaller than or equal to 64.');
+        }
+        if ($password !== null && strlen($password) < 10) {
+            throw new \InvalidArgumentException('invalid length for "$password" when calling FakeApi.testEndpointParameters, must be bigger than or equal to 10.');
+        }
+
 
         $resourcePath = '/fake';
         $formParams = [];
@@ -1474,6 +1583,62 @@ class FakeApi
 
 
 
+        // form params
+        if ($integer !== null) {
+            $formParams['integer'] = ObjectSerializer::toFormValue($integer);
+        }
+        // form params
+        if ($int32 !== null) {
+            $formParams['int32'] = ObjectSerializer::toFormValue($int32);
+        }
+        // form params
+        if ($int64 !== null) {
+            $formParams['int64'] = ObjectSerializer::toFormValue($int64);
+        }
+        // form params
+        if ($number !== null) {
+            $formParams['number'] = ObjectSerializer::toFormValue($number);
+        }
+        // form params
+        if ($float !== null) {
+            $formParams['float'] = ObjectSerializer::toFormValue($float);
+        }
+        // form params
+        if ($double !== null) {
+            $formParams['double'] = ObjectSerializer::toFormValue($double);
+        }
+        // form params
+        if ($string !== null) {
+            $formParams['string'] = ObjectSerializer::toFormValue($string);
+        }
+        // form params
+        if ($pattern_without_delimiter !== null) {
+            $formParams['pattern_without_delimiter'] = ObjectSerializer::toFormValue($pattern_without_delimiter);
+        }
+        // form params
+        if ($byte !== null) {
+            $formParams['byte'] = ObjectSerializer::toFormValue($byte);
+        }
+        // form params
+        if ($binary !== null) {
+            $formParams['binary'] = ObjectSerializer::toFormValue($binary);
+        }
+        // form params
+        if ($date !== null) {
+            $formParams['date'] = ObjectSerializer::toFormValue($date);
+        }
+        // form params
+        if ($date_time !== null) {
+            $formParams['dateTime'] = ObjectSerializer::toFormValue($date_time);
+        }
+        // form params
+        if ($password !== null) {
+            $formParams['password'] = ObjectSerializer::toFormValue($password);
+        }
+        // form params
+        if ($callback !== null) {
+            $formParams['callback'] = ObjectSerializer::toFormValue($callback);
+        }
         // body params
         $_tempBody = null;
 
@@ -1552,14 +1717,17 @@ class FakeApi
      * @param  string[] $enum_query_string_array Query parameter enum test (string array) (optional)
      * @param  string $enum_query_string Query parameter enum test (string) (optional)
      * @param  int $enum_query_integer Query parameter enum test (double) (optional)
+     * @param  string[] $enum_form_string_array Form parameter enum test (string array) (optional)
+     * @param  string $enum_form_string Form parameter enum test (string) (optional)
+     * @param  double $enum_query_double Query parameter enum test (double) (optional)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
      * @return void
      */
-    public function testEnumParameters($enum_header_string_array = null, $enum_header_string = null, $enum_query_string_array = null, $enum_query_string = null, $enum_query_integer = null)
+    public function testEnumParameters($enum_header_string_array = null, $enum_header_string = null, $enum_query_string_array = null, $enum_query_string = null, $enum_query_integer = null, $enum_form_string_array = null, $enum_form_string = null, $enum_query_double = null)
     {
-        $this->testEnumParametersWithHttpInfo($enum_header_string_array, $enum_header_string, $enum_query_string_array, $enum_query_string, $enum_query_integer);
+        $this->testEnumParametersWithHttpInfo($enum_header_string_array, $enum_header_string, $enum_query_string_array, $enum_query_string, $enum_query_integer, $enum_form_string_array, $enum_form_string, $enum_query_double);
     }
 
     /**
@@ -1572,15 +1740,18 @@ class FakeApi
      * @param  string[] $enum_query_string_array Query parameter enum test (string array) (optional)
      * @param  string $enum_query_string Query parameter enum test (string) (optional)
      * @param  int $enum_query_integer Query parameter enum test (double) (optional)
+     * @param  string[] $enum_form_string_array Form parameter enum test (string array) (optional)
+     * @param  string $enum_form_string Form parameter enum test (string) (optional)
+     * @param  double $enum_query_double Query parameter enum test (double) (optional)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
      * @return array of null, HTTP status code, HTTP response headers (array of strings)
      */
-    public function testEnumParametersWithHttpInfo($enum_header_string_array = null, $enum_header_string = null, $enum_query_string_array = null, $enum_query_string = null, $enum_query_integer = null)
+    public function testEnumParametersWithHttpInfo($enum_header_string_array = null, $enum_header_string = null, $enum_query_string_array = null, $enum_query_string = null, $enum_query_integer = null, $enum_form_string_array = null, $enum_form_string = null, $enum_query_double = null)
     {
         $returnType = '';
-        $request = $this->testEnumParametersRequest($enum_header_string_array, $enum_header_string, $enum_query_string_array, $enum_query_string, $enum_query_integer);
+        $request = $this->testEnumParametersRequest($enum_header_string_array, $enum_header_string, $enum_query_string_array, $enum_query_string, $enum_query_integer, $enum_form_string_array, $enum_form_string, $enum_query_double);
 
         try {
             $options = $this->createHttpClientOption();
@@ -1629,13 +1800,16 @@ class FakeApi
      * @param  string[] $enum_query_string_array Query parameter enum test (string array) (optional)
      * @param  string $enum_query_string Query parameter enum test (string) (optional)
      * @param  int $enum_query_integer Query parameter enum test (double) (optional)
+     * @param  string[] $enum_form_string_array Form parameter enum test (string array) (optional)
+     * @param  string $enum_form_string Form parameter enum test (string) (optional)
+     * @param  double $enum_query_double Query parameter enum test (double) (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function testEnumParametersAsync($enum_header_string_array = null, $enum_header_string = null, $enum_query_string_array = null, $enum_query_string = null, $enum_query_integer = null)
+    public function testEnumParametersAsync($enum_header_string_array = null, $enum_header_string = null, $enum_query_string_array = null, $enum_query_string = null, $enum_query_integer = null, $enum_form_string_array = null, $enum_form_string = null, $enum_query_double = null)
     {
-        return $this->testEnumParametersAsyncWithHttpInfo($enum_header_string_array, $enum_header_string, $enum_query_string_array, $enum_query_string, $enum_query_integer)
+        return $this->testEnumParametersAsyncWithHttpInfo($enum_header_string_array, $enum_header_string, $enum_query_string_array, $enum_query_string, $enum_query_integer, $enum_form_string_array, $enum_form_string, $enum_query_double)
             ->then(
                 function ($response) {
                     return $response[0];
@@ -1653,14 +1827,17 @@ class FakeApi
      * @param  string[] $enum_query_string_array Query parameter enum test (string array) (optional)
      * @param  string $enum_query_string Query parameter enum test (string) (optional)
      * @param  int $enum_query_integer Query parameter enum test (double) (optional)
+     * @param  string[] $enum_form_string_array Form parameter enum test (string array) (optional)
+     * @param  string $enum_form_string Form parameter enum test (string) (optional)
+     * @param  double $enum_query_double Query parameter enum test (double) (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function testEnumParametersAsyncWithHttpInfo($enum_header_string_array = null, $enum_header_string = null, $enum_query_string_array = null, $enum_query_string = null, $enum_query_integer = null)
+    public function testEnumParametersAsyncWithHttpInfo($enum_header_string_array = null, $enum_header_string = null, $enum_query_string_array = null, $enum_query_string = null, $enum_query_integer = null, $enum_form_string_array = null, $enum_form_string = null, $enum_query_double = null)
     {
         $returnType = '';
-        $request = $this->testEnumParametersRequest($enum_header_string_array, $enum_header_string, $enum_query_string_array, $enum_query_string, $enum_query_integer);
+        $request = $this->testEnumParametersRequest($enum_header_string_array, $enum_header_string, $enum_query_string_array, $enum_query_string, $enum_query_integer, $enum_form_string_array, $enum_form_string, $enum_query_double);
 
         return $this->client
             ->sendAsync($request, $this->createHttpClientOption())
@@ -1693,11 +1870,14 @@ class FakeApi
      * @param  string[] $enum_query_string_array Query parameter enum test (string array) (optional)
      * @param  string $enum_query_string Query parameter enum test (string) (optional)
      * @param  int $enum_query_integer Query parameter enum test (double) (optional)
+     * @param  string[] $enum_form_string_array Form parameter enum test (string array) (optional)
+     * @param  string $enum_form_string Form parameter enum test (string) (optional)
+     * @param  double $enum_query_double Query parameter enum test (double) (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
      */
-    protected function testEnumParametersRequest($enum_header_string_array = null, $enum_header_string = null, $enum_query_string_array = null, $enum_query_string = null, $enum_query_integer = null)
+    protected function testEnumParametersRequest($enum_header_string_array = null, $enum_header_string = null, $enum_query_string_array = null, $enum_query_string = null, $enum_query_integer = null, $enum_form_string_array = null, $enum_form_string = null, $enum_query_double = null)
     {
 
         $resourcePath = '/fake';
@@ -1732,6 +1912,18 @@ class FakeApi
         }
 
 
+        // form params
+        if ($enum_form_string_array !== null) {
+            $formParams['enum_form_string_array'] = ObjectSerializer::toFormValue($enum_form_string_array);
+        }
+        // form params
+        if ($enum_form_string !== null) {
+            $formParams['enum_form_string'] = ObjectSerializer::toFormValue($enum_form_string);
+        }
+        // form params
+        if ($enum_query_double !== null) {
+            $formParams['enum_query_double'] = ObjectSerializer::toFormValue($enum_query_double);
+        }
         // body params
         $_tempBody = null;
 
@@ -2021,14 +2213,16 @@ class FakeApi
      *
      * test json serialization of form data
      *
+     * @param  string $param field1 (optional)
+     * @param  string $param2 field2 (optional)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
      * @return void
      */
-    public function testJsonFormData()
+    public function testJsonFormData($param = null, $param2 = null)
     {
-        $this->testJsonFormDataWithHttpInfo();
+        $this->testJsonFormDataWithHttpInfo($param, $param2);
     }
 
     /**
@@ -2036,15 +2230,17 @@ class FakeApi
      *
      * test json serialization of form data
      *
+     * @param  string $param field1 (optional)
+     * @param  string $param2 field2 (optional)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
      * @return array of null, HTTP status code, HTTP response headers (array of strings)
      */
-    public function testJsonFormDataWithHttpInfo()
+    public function testJsonFormDataWithHttpInfo($param = null, $param2 = null)
     {
         $returnType = '';
-        $request = $this->testJsonFormDataRequest();
+        $request = $this->testJsonFormDataRequest($param, $param2);
 
         try {
             $options = $this->createHttpClientOption();
@@ -2088,13 +2284,15 @@ class FakeApi
      *
      * test json serialization of form data
      *
+     * @param  string $param field1 (optional)
+     * @param  string $param2 field2 (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function testJsonFormDataAsync()
+    public function testJsonFormDataAsync($param = null, $param2 = null)
     {
-        return $this->testJsonFormDataAsyncWithHttpInfo()
+        return $this->testJsonFormDataAsyncWithHttpInfo($param, $param2)
             ->then(
                 function ($response) {
                     return $response[0];
@@ -2107,14 +2305,16 @@ class FakeApi
      *
      * test json serialization of form data
      *
+     * @param  string $param field1 (optional)
+     * @param  string $param2 field2 (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function testJsonFormDataAsyncWithHttpInfo()
+    public function testJsonFormDataAsyncWithHttpInfo($param = null, $param2 = null)
     {
         $returnType = '';
-        $request = $this->testJsonFormDataRequest();
+        $request = $this->testJsonFormDataRequest($param, $param2);
 
         return $this->client
             ->sendAsync($request, $this->createHttpClientOption())
@@ -2142,11 +2342,13 @@ class FakeApi
     /**
      * Create request for operation 'testJsonFormData'
      *
+     * @param  string $param field1 (optional)
+     * @param  string $param2 field2 (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
      */
-    protected function testJsonFormDataRequest()
+    protected function testJsonFormDataRequest($param = null, $param2 = null)
     {
 
         $resourcePath = '/fake/jsonFormData';
@@ -2158,6 +2360,14 @@ class FakeApi
 
 
 
+        // form params
+        if ($param !== null) {
+            $formParams['param'] = ObjectSerializer::toFormValue($param);
+        }
+        // form params
+        if ($param2 !== null) {
+            $formParams['param2'] = ObjectSerializer::toFormValue($param2);
+        }
         // body params
         $_tempBody = null;
 
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/PetApi.php b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/PetApi.php
index bce65b0d6a2..a0fb0b9a48e 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/PetApi.php
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/PetApi.php
@@ -1576,14 +1576,16 @@ class PetApi
      * Updates a pet in the store with form data
      *
      * @param  int $pet_id ID of pet that needs to be updated (required)
+     * @param  string $name Updated name of the pet (optional)
+     * @param  string $status Updated status of the pet (optional)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
      * @return void
      */
-    public function updatePetWithForm($pet_id)
+    public function updatePetWithForm($pet_id, $name = null, $status = null)
     {
-        $this->updatePetWithFormWithHttpInfo($pet_id);
+        $this->updatePetWithFormWithHttpInfo($pet_id, $name, $status);
     }
 
     /**
@@ -1592,15 +1594,17 @@ class PetApi
      * Updates a pet in the store with form data
      *
      * @param  int $pet_id ID of pet that needs to be updated (required)
+     * @param  string $name Updated name of the pet (optional)
+     * @param  string $status Updated status of the pet (optional)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
      * @return array of null, HTTP status code, HTTP response headers (array of strings)
      */
-    public function updatePetWithFormWithHttpInfo($pet_id)
+    public function updatePetWithFormWithHttpInfo($pet_id, $name = null, $status = null)
     {
         $returnType = '';
-        $request = $this->updatePetWithFormRequest($pet_id);
+        $request = $this->updatePetWithFormRequest($pet_id, $name, $status);
 
         try {
             $options = $this->createHttpClientOption();
@@ -1645,13 +1649,15 @@ class PetApi
      * Updates a pet in the store with form data
      *
      * @param  int $pet_id ID of pet that needs to be updated (required)
+     * @param  string $name Updated name of the pet (optional)
+     * @param  string $status Updated status of the pet (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function updatePetWithFormAsync($pet_id)
+    public function updatePetWithFormAsync($pet_id, $name = null, $status = null)
     {
-        return $this->updatePetWithFormAsyncWithHttpInfo($pet_id)
+        return $this->updatePetWithFormAsyncWithHttpInfo($pet_id, $name, $status)
             ->then(
                 function ($response) {
                     return $response[0];
@@ -1665,14 +1671,16 @@ class PetApi
      * Updates a pet in the store with form data
      *
      * @param  int $pet_id ID of pet that needs to be updated (required)
+     * @param  string $name Updated name of the pet (optional)
+     * @param  string $status Updated status of the pet (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function updatePetWithFormAsyncWithHttpInfo($pet_id)
+    public function updatePetWithFormAsyncWithHttpInfo($pet_id, $name = null, $status = null)
     {
         $returnType = '';
-        $request = $this->updatePetWithFormRequest($pet_id);
+        $request = $this->updatePetWithFormRequest($pet_id, $name, $status);
 
         return $this->client
             ->sendAsync($request, $this->createHttpClientOption())
@@ -1701,11 +1709,13 @@ class PetApi
      * Create request for operation 'updatePetWithForm'
      *
      * @param  int $pet_id ID of pet that needs to be updated (required)
+     * @param  string $name Updated name of the pet (optional)
+     * @param  string $status Updated status of the pet (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
      */
-    protected function updatePetWithFormRequest($pet_id)
+    protected function updatePetWithFormRequest($pet_id, $name = null, $status = null)
     {
         // verify the required parameter 'pet_id' is set
         if ($pet_id === null || (is_array($pet_id) && count($pet_id) === 0)) {
@@ -1731,6 +1741,14 @@ class PetApi
             );
         }
 
+        // form params
+        if ($name !== null) {
+            $formParams['name'] = ObjectSerializer::toFormValue($name);
+        }
+        // form params
+        if ($status !== null) {
+            $formParams['status'] = ObjectSerializer::toFormValue($status);
+        }
         // body params
         $_tempBody = null;
 
@@ -1805,14 +1823,16 @@ class PetApi
      * uploads an image
      *
      * @param  int $pet_id ID of pet to update (required)
+     * @param  string $additional_metadata Additional data to pass to server (optional)
+     * @param  string $file file to upload (optional)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
      * @return \Swagger\Client\Model\ApiResponse
      */
-    public function uploadFile($pet_id)
+    public function uploadFile($pet_id, $additional_metadata = null, $file = null)
     {
-        list($response) = $this->uploadFileWithHttpInfo($pet_id);
+        list($response) = $this->uploadFileWithHttpInfo($pet_id, $additional_metadata, $file);
         return $response;
     }
 
@@ -1822,15 +1842,17 @@ class PetApi
      * uploads an image
      *
      * @param  int $pet_id ID of pet to update (required)
+     * @param  string $additional_metadata Additional data to pass to server (optional)
+     * @param  string $file file to upload (optional)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
      * @return array of \Swagger\Client\Model\ApiResponse, HTTP status code, HTTP response headers (array of strings)
      */
-    public function uploadFileWithHttpInfo($pet_id)
+    public function uploadFileWithHttpInfo($pet_id, $additional_metadata = null, $file = null)
     {
         $returnType = '\Swagger\Client\Model\ApiResponse';
-        $request = $this->uploadFileRequest($pet_id);
+        $request = $this->uploadFileRequest($pet_id, $additional_metadata, $file);
 
         try {
             $options = $this->createHttpClientOption();
@@ -1897,13 +1919,15 @@ class PetApi
      * uploads an image
      *
      * @param  int $pet_id ID of pet to update (required)
+     * @param  string $additional_metadata Additional data to pass to server (optional)
+     * @param  string $file file to upload (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function uploadFileAsync($pet_id)
+    public function uploadFileAsync($pet_id, $additional_metadata = null, $file = null)
     {
-        return $this->uploadFileAsyncWithHttpInfo($pet_id)
+        return $this->uploadFileAsyncWithHttpInfo($pet_id, $additional_metadata, $file)
             ->then(
                 function ($response) {
                     return $response[0];
@@ -1917,14 +1941,16 @@ class PetApi
      * uploads an image
      *
      * @param  int $pet_id ID of pet to update (required)
+     * @param  string $additional_metadata Additional data to pass to server (optional)
+     * @param  string $file file to upload (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function uploadFileAsyncWithHttpInfo($pet_id)
+    public function uploadFileAsyncWithHttpInfo($pet_id, $additional_metadata = null, $file = null)
     {
         $returnType = '\Swagger\Client\Model\ApiResponse';
-        $request = $this->uploadFileRequest($pet_id);
+        $request = $this->uploadFileRequest($pet_id, $additional_metadata, $file);
 
         return $this->client
             ->sendAsync($request, $this->createHttpClientOption())
@@ -1967,11 +1993,13 @@ class PetApi
      * Create request for operation 'uploadFile'
      *
      * @param  int $pet_id ID of pet to update (required)
+     * @param  string $additional_metadata Additional data to pass to server (optional)
+     * @param  string $file file to upload (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
      */
-    protected function uploadFileRequest($pet_id)
+    protected function uploadFileRequest($pet_id, $additional_metadata = null, $file = null)
     {
         // verify the required parameter 'pet_id' is set
         if ($pet_id === null || (is_array($pet_id) && count($pet_id) === 0)) {
@@ -1997,6 +2025,14 @@ class PetApi
             );
         }
 
+        // form params
+        if ($additional_metadata !== null) {
+            $formParams['additionalMetadata'] = ObjectSerializer::toFormValue($additional_metadata);
+        }
+        // form params
+        if ($file !== null) {
+            $formParams['file'] = ObjectSerializer::toFormValue($file);
+        }
         // body params
         $_tempBody = null;