[5.0] Fix empty morph to relationship

[lukasgeiter]

This fixes issue #8499

[GrahamCampbell]

just return; please

[mtvs]

It doesn't work for me (5.0)

FatalErrorException in Model.php line 873: Class '' not found

1. in Model.php line 873
2. at FatalErrorException->__construct('message' => '', 'code' => '', 'severity' => '', 'filename' => '', 'lineno' => '', 'traceOffset' => '', 'traceArgs' => '') in HandleExceptions.php line 131
3. at HandleExceptions->fatalExceptionFromError('error' => '', 'traceOffset' => '') in HandleExceptions.php line 116
4. at HandleExceptions->handleShutdown() in HandleExceptions.php line 0
5. at Model->morphTo('name' => '', 'type' => '', 'id' => '') in Code.php line 38

even when I set the morph fields to null, still it causes a QueryException but when I provide the right values for the fields the relation works as expected.

[lukasgeiter]

I'd need to see some more of your code to help you... Also that part Class '' not found looks a lot like your type field is not null but rather an empty string. Please check that first.

[mtvs]

Thanks for your willingness to help.

I think it should work with empty strings too, because the Blueprint::morphs() doesn't create nullable columns.

Anyway as I said I tried it with null morph columns too, but this doesn't work for me.

I have the following methods in my Code model:

// App\Code.php
/**
 * @return \Illuminate\Database\Eloquent\Relations\MorphTo
 */
public function input()
{
    return $this->morphTo('input');
}

/**
 * @return bool
 */
public function hasBeenUsed()
{
    return $this->input()->count() ? true : false;
}

when the hasBeenUsed() is called, it should count the number of the related inputs but the error log shows that the query is executed against the codes table.

QueryException in Connection.php line 620: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'codes.' in 'where clause' (SQL: select count as aggregate from `codes` where `codes`.`` is null)

in Connection.php line 620
at Connection->runQueryCallback('select count as aggregate from `codes` where `codes`.`` is null', array(), object(Closure)) in Connection.php line 576
at Connection->run('select count as aggregate from `codes` where `codes`.`` is null', array(), object(Closure)) in Connection.php line 293
at Connection->select('select count as aggregate from `codes` where `codes`.`` is null', array(), true) in Builder.php line 1377
at Builder->runSelect() in Builder.php line 1367
at Builder->getFresh(array('*')) in Builder.php line 1354
at Builder->get(array('*')) in Builder.php line 1636
at Builder->aggregate('count', array('*')) in Builder.php line 1574
at Builder->count()
at call_user_func_array(array(object(Builder), 'count'), array()) in Builder.php line 933
at Builder->__call('count', array())
at Builder->count()
at call_user_func_array(array(object(Builder), 'count'), array()) in Relation.php line 283
at Relation->__call('count', array()) in Code.php line 46
at MorphTo->count() in Code.php line 46
at Code->hasBeenUsed() in InputHandler.php line 36
at InputHandler->handle(object(WebInput)) in ParticipantsController.php line 29