MAGETWO-94819: Swatch validation breaks the whole attribute form

Author: fascinosum

app/code/Magento/Catalog/Controller/Adminhtml/Product/Attribute/Save.php

@@ -140,7 +140,7 @@ public function execute()
     {
         try {
             $optionData = $this->optionsDataSerializer
-                ->unserialize($this->getRequest()->getParam('serialized_options'));
+                ->unserialize($this->getRequest()->getParam('serialized_options', '[]'));
         } catch (\InvalidArgumentException $e) {
             $message = __("The attribute couldn't be saved due to an error. Verify your information and try again. "
                 . "If the error persists, please try again later.");

app/code/Magento/Catalog/Controller/Adminhtml/Product/Attribute/Validate.php

@@ -83,7 +83,7 @@ public function execute()
         $response->setError(false);
         try {
             $optionsData = $this->optionsDataSerializer
-                ->unserialize($this->getRequest()->getParam('serialized_options'));
+                ->unserialize($this->getRequest()->getParam('serialized_options', '[]'));
         } catch (\InvalidArgumentException $e) {
             $message = __("The attribute couldn't be validated due to an error. Verify your information and try again. "
                 . "If the error persists, please try again later.");

app/code/Magento/Catalog/Test/Mftf/Test/AdminEditTextEditorProductAttributeTest.xml

@@ -26,10 +26,9 @@
                 <requiredEntity createDataKey="myProductAttributeCreation"/>
             </createData>
         </before>
-        <amOnPage url="{{AdminProductAttributeGridPage.url}}" stepKey="navigateToProductAttributeGrid1"/>
-        <waitForPageLoad stepKey="waitForPageLoad1"/>
-        <click selector="{{AdminProductAttributeGridSection.AttributeCode($$myProductAttributeCreation.attribute_code$$)}}" stepKey="navigateToAttributeEditPage1" />
-        <waitForPageLoad stepKey="waitForPageLoad2" />
+        <actionGroup ref="navigateToCreatedProductAttribute" stepKey="navigateToAttribute">
+            <argument name="ProductAttribute" value="productAttributeWysiwyg"/>
+        </actionGroup>
         <seeOptionIsSelected selector="{{AttributePropertiesSection.InputType}}" userInput="Text Editor" stepKey="seeTextEditorSelected" />
         <see selector="{{AttributePropertiesSection.InputType}}" userInput="Text Area" stepKey="seeTextArea1" />
         <selectOption selector="{{AttributePropertiesSection.InputType}}" userInput="Text Area"  stepKey="selectTextArea" />

app/code/Magento/Catalog/Test/Unit/Controller/Adminhtml/Product/Attribute/SaveTest.php

@@ -180,7 +180,7 @@ public function testExecuteWithEmptyData()
             ->method('getParam')
             ->willReturnMap([
                 ['isAjax', null, null],
-                ['serialized_options', null, ''],
+                ['serialized_options', '[]', ''],
             ]);
         $this->optionsDataSerializerMock
             ->expects($this->once())
@@ -211,7 +211,7 @@ public function testExecute()
             ->method('getParam')
             ->willReturnMap([
                 ['isAjax', null, null],
-                ['serialized_options', null, ''],
+                ['serialized_options', '[]', ''],
             ]);
         $this->optionsDataSerializerMock
             ->expects($this->once())
@@ -271,7 +271,7 @@ public function testExecuteWithOptionsDataError()
             ->method('getParam')
             ->willReturnMap([
                 ['isAjax', null, true],
-                ['serialized_options', null, $serializedOptions],
+                ['serialized_options', '[]', $serializedOptions],
             ]);
         $this->optionsDataSerializerMock
             ->expects($this->once())

app/code/Magento/Catalog/Test/Unit/Controller/Adminhtml/Product/Attribute/ValidateTest.php

@@ -130,7 +130,7 @@ public function testExecute()
                 ['frontend_label', null, 'test_frontend_label'],
                 ['attribute_code', null, 'test_attribute_code'],
                 ['new_attribute_set_name', null, 'test_attribute_set_name'],
-                ['serialized_options', null, $serializedOptions],
+                ['serialized_options', '[]', $serializedOptions],
             ]);
         $this->objectManagerMock->expects($this->exactly(2))
             ->method('create')
@@ -181,7 +181,7 @@ public function testUniqueValidation(array $options, $isError)
                 ['attribute_code', null, "test_attribute_code"],
                 ['new_attribute_set_name', null, 'test_attribute_set_name'],
                 ['message_key', null, Validate::DEFAULT_MESSAGE_KEY],
-                ['serialized_options', null, $serializedOptions],
+                ['serialized_options', '[]', $serializedOptions],
             ]);
 
         $this->optionsDataSerializerMock
@@ -316,7 +316,7 @@ public function testEmptyOption(array $options, $result)
                 ['attribute_code', null, "test_attribute_code"],
                 ['new_attribute_set_name', null, 'test_attribute_set_name'],
                 ['message_key', Validate::DEFAULT_MESSAGE_KEY, 'message'],
-                ['serialized_options', null, $serializedOptions],
+                ['serialized_options', '[]', $serializedOptions],
             ]);
 
         $this->optionsDataSerializerMock
@@ -428,7 +428,7 @@ public function testExecuteWithOptionsDataError()
                 ['attribute_code', null, 'test_attribute_code'],
                 ['new_attribute_set_name', null, 'test_attribute_set_name'],
                 ['message_key', Validate::DEFAULT_MESSAGE_KEY, 'message'],
-                ['serialized_options', null, $serializedOptions],
+                ['serialized_options', '[]', $serializedOptions],
             ]);
 
         $this->optionsDataSerializerMock