$withCount breaks replicate()

[tobz-nz]

• Laravel Version: 5.7.13
• PHP Version: 7.2.9
• Database Driver & Version: mysql / ?

Description:

As in other cases(that have all been fixed I think), a model with a polymorphic relation and a $withCount property fails to replicate()

Steps To Reproduce:

class Board extends Model {
public $withCount = ['profiles'];
public function profiles()
    {
        return $this->morphedByMany(User::class, 'profilable');
    }
}

$b = Board::first();
$b2 = $b->replicate();
$b2->save();

Results in the error:
Column not found: 1054 Unknown column 'profiles_count' in 'field list' ...

Expected $b2 to be a new Board instance with same properties as original.

[tobz-nz]

Am getting past this currently by manually passing in the count property to the replicate($except) param.

$b->replicate(['profiles_count'])

This should be pretty easy to fix by using the withCount property in replicate's internal filtering.
...although that won't help for manually counted relations (loaded after the fact using withCount()).

I don't think there's a register for counted relations (ala the $model->relations array)

[staudenmeir]

You are calling save() afterwards, right? replicate() itself doesn't trigger the error.

[tobz-nz]

Ah yes - sorry, missed that part.

[staudenmeir]

I don't think we can make this assumption. There could be users who except the profiles_count attribute in the replicated model. Maybe they don't want to save it but use it for something else.

[tobz-nz]

Yep, Good point.
Maybe a register of all loaded withCount's and ignore them on save?

Or maybe move where the count is stored from the attributes array to something else and do a check in getAttribute()? That could be a BC issue though aye?

[staudenmeir]

I'm not sure it's worth the effort.

[tobz-nz]

Seems like a pretty bad bug to me. If you have a polymorphic relation and a withCount you can't replicate?
I realize its a little bit of a edge case but still...

[staudenmeir]

It's my impression that $withCount is not widely used, especially in combination with replicate(). IMO, using $expect $except is good enough as a workaround.

[tobz-nz]

Whats $expect? I've not seen this.

[staudenmeir]

Sorry, I meant $except (the parameter of replicate()).

[tobz-nz]

Ah, haha here I am searching through the code for $expect :)

yeah fair enough. At least there's a record of the issue here now for others (and myself in the future when I've forgotten about it)

[staudenmeir]

Somewhat related: #25495

[tobz-nz]

Yes I think that's the same underlying issue.

Also TIL about storedAs :)

[staudenmeir]

The fundamental "issue" is that Laravel (unlike some other frameworks) doesn't know what columns the table contains, so there is no solution that can cover all cases. As you mentioned, we could fix it for $withCount but not for withCount().

[tobz-nz]

Unless you move the count value out of the main attributes array to something like $withCounts? and access that via the getAttribute() method.

but doing that could break people code if they're accessing the count directly on $attributes - so that's probably a no go as well.

well, I suppose it could go into 5.8?