Select Specific _joinData Fields to Update in PatchEntity

1

hi,

I am trying to only update the tags._joinData.quantity field. But I am unable to set the patchEntity to only allow that field.

$formData = $this->request->getData();


// Test inject
$formData['title'] = 'This should not be edited ' . date('h:i:s');
$formData['tags'][0]['description'] = 'This should not be edited ' . date('h:i:s');


$article = $this->Articles->patchEntity($article, $formData, [
	'fields' => [ '*' => false,  ],
	'associated' => [
		'Tags' =>
		[
			'description' => false,
			'_joinData' => ['fields' => ['quantity']],
                // does not work too
                // '_joinData' => [
                //    'accessibleFields' => ['description' => false, 'quantity' => true]
                //  ] 
		]   



	],

]);
$article->setDirty('tags');


$this->Articles->save($article);

In the code above,

  1. title field is not patched/updated because of the '*' => false condition. Not sure whether this is the right way as I don’t see any document on this.
  2. quantity field is updated together with the description field.

The problem is I don’t want any other fields to be updated except quantity field in the _joinData.