[5.x] Ensure null values are filtered out in dictionary field config (#11773)

Author: duncanmcclean

src/Fieldtypes/DictionaryFields.php

@@ -71,7 +71,7 @@ public function process($data): string|array
             return $dictionary->handle();
         }
 
-        return array_merge(['type' => $dictionary->handle()], $values->all());
+        return array_merge(['type' => $dictionary->handle()], $values->filter()->all());
     }
 
     public function extraRules(): array

tests/Fieldtypes/DictionaryFieldsTest.php

@@ -116,6 +116,23 @@ public function it_processes_dictionary_fields_into_a_string_when_dictionary_has
         $this->assertEquals('fake_dictionary', $process);
     }
 
+    #[Test]
+    public function it_processes_dictionary_fields_and_filters_out_null_values()
+    {
+        $fieldtype = FieldtypeRepository::find('dictionary_fields');
+
+        $process = $fieldtype->process([
+            'type' => 'fake_dictionary',
+            'category' => 'foo',
+            'foo' => null,
+        ]);
+
+        $this->assertEquals([
+            'type' => 'fake_dictionary',
+            'category' => 'foo',
+        ], $process);
+    }
+
     #[Test]
     public function it_returns_validation_rules()
     {