relatableQuery dependsOn belongsTo value

[mrleblanc101]

Hi,
I have this relationship structure.

Serie:

• id
• title

Seasons:

• id
• title
• serie_id

Episodes:

• id
• title
• season_id

Here is what I want to achieve:

I want the second BelongsTo to be filtered by the value of the first BelongsTo.

When I create an Episode, I need to select which Season the Episode belongsTo.
The problem is that many Series have "Season 1".

As a workaround, I added the Serie name to the title of the Season using this code:

public function title() {
    return $this->serie->title . ' - ' . $this->title;
}

The problem is that I don't find this satisfactory.
I would love for the User to select the Serie in a computed dropdown (since the serie is a belongsThrought relationship, we don't want to save this on the Episode model).

I have a working prototype.
In my fields, I added a BelongsTo Serie field from a belongsThrough relationship.
This break when saving, so I used ->fillUsing(function() {}), to not save this value, this seems like a hack.

Then, to filter the values of the Season dropdown, I created a relatableSeasons.
The function receive the value of the Serie dropdown on change and apply a where.
But since this function is called twice, the second time (for the associatable query) which doesn't have the param, it remove my filter. So I used the session to save the value for the second call.

public static function relatableSeasons(NovaRequest $request, $query)
{
    if(!$request->viaResource()) {
        if($request->serie) {
            $request->session()->put('serie_id', $request->serie);
        }
        if($request->session()->get('serie_id')){
            return $query->where('serie_id', (int) $request->session()->get('serie_id'));
        }
    }
}

Any idea how I can have a Grand-parent -> Parent ->Child relationship without all these ugly hacks to filter the BelongsTo fields ?

[crynobone]

Implemented in Nova 4.19.0

You can now do the following:

BelongsTo::make('User')
  ->dependsOn('role', function ($field, $request, $formData) {
    if (! empty($formData->role)) {
      $field->relatableQueryUsing(
        fn ($request, $query) => $query->whereIn('id', [$form->role]))
      );
    }
  }),