cakephp: Saving Model with first-level BTM associations will fail silently, if the BTM field is not accessible

This is a (multiple allowed):

• bug

• enhancement

• feature-discussion (RFC)

• CakePHP Version: 3.7.3

• Platform and Target: linux php7.3 nginx

While dev/testing i’ve baked three models

• documents
• document_types
• document_types_documents

Having done some changes, i’ve manually added belongsToMany from Documents to DocumentTypes

Setting data correctly through Form->control('document_types._ids', ['options'=>$arr])

What was not working is saving data, and there is no warning/error about it.

DocumentsTable $_accessible was missing property 'document_types'=>true which corresponds with belongsToMany alias, adding it fixed everything.

So I’d like to know, if it is possible to make such situation developer-detectable, that Documents->patchEntity($document, $this->request->getData()) does not set the BTM fields (or generate appropriate entitites), because of the BTM alias/field accessibility

It is currently not even detectable from contents of $document (in this case) entity after patching, because neither dirty, original or other fields, that could hint such problem, do not reflect this.

Thank you