Related link does gives 404 for manyToOne custom association

[geoidesic]

Given a people and enquiries table:

$this->table('enquiries', ['id' => false, 'primary_key' => ['id']])
            ->addColumn('created', 'datetime', [
                'default' => 'CURRENT_TIMESTAMP',
                'limit' => null,
                'null' => true,
            ])
            ->addColumn('id', 'uuid', [
                'default' => null,
                'limit' => null,
                'null' => false,
            ])
            ->addColumn('notary_id', 'uuid', [
                'comment' => 'Notary responsible for taking this enquiry forward (and for billing), not necessarily the same as logged in user',
                'default' => null,
                'limit' => null,
                'null' => false,
            ])
...
 $this->table('people', ['id' => false, 'primary_key' => ['id']])
            ->addColumn('id', 'uuid', [
                'default' => null,
                'limit' => null,
                'null' => false,
            ])

I wish to associate enquiries.notary_id to person.id as a manyToOne. In order to do so, I have the following association on the EnquiriesTable:

        $this->belongsTo('Notaries', ['className' => 'People', 'foreignKey' => 'notary_id']);

This partly works – but the links provided via JSONAPI are not all valid:

• links: self is functional
• links: related is broken; goes to a 404 with error: "No valid relationship found"

 "notary": {
                "links": {
                    "self": "/api/enquiries/73ac53d0-3fdb-4300-bc6c-09b9e534cced/relationships/notary",
                    "related": "/api/enquiries/73ac53d0-3fdb-4300-bc6c-09b9e534cced/notary"
                },

It looks like something is wrong with the association reverse lookup. Looking deeper, it seems to be that if one is using an aliased foreignKey then the association is not picked up and listed in $table->_associations. So this may be a deeper problem with Cake itself.

[geoidesic]

Looks like the reverse association on PeopleTable was missing:

        $this->hasMany('NotaryEnquiries', ['className' => 'Enquiries', 'foreignKey' => 'notary_id']);