Why HasOneThrough does not prevent the sql when the farParent key is null?

[macropay-solutions]

Index: illuminate/Database/Eloquent/Relations/HasOneThrough.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/illuminate/Database/Eloquent/Relations/HasOneThrough.php b/illuminate/Database/Eloquent/Relations/HasOneThrough.php
--- a/illuminate/Database/Eloquent/Relations/HasOneThrough.php	(revision 244032c422b541f1df1c5e1bae2e020ae195f9a8)
+++ b/illuminate/Database/Eloquent/Relations/HasOneThrough.php	(date 1774384471161)
@@ -19,7 +19,8 @@
      */
     public function getResults()
     {
-        return $this->first() ?: $this->getDefaultFor($this->farParent);
+        return (null !== $this->farParent->{$this->localKey} ? $this->first() : null)
+            ?? $this->getDefaultFor($this->farParent);
     }
 
     /**

HasOneThrough is a child of HasmanyThrough:

    public function getResults()
    {
        return !is_null($this->farParent->{$this->localKey})
            ? $this->get()
            : $this->related->newCollection();
    }

[de-lazurenko]

Inconsistency between HasOneThrough and HasManyThrough
There is a clear inconsistency in how Eloquent handles "Through" relationships when the farParent key is null.

HasManyThrough already prevents unnecessary queries:

// HasManyThrough.php
public function getResults()
{
    return !is_null($this->farParent->{$this->localKey}) 
        ? $this->get() 
        : $this->related->newCollection();
}

However, HasOneThrough currently lacks this check, leading to an redundant SQL execution that will always return empty results (or the default model) when the key is null.

Proposed change for my side:
Align HasOneThrough::getResults() with its parent's logic to improve performance and consistency:

public function getResults()
{
    return (null !== $this->farParent->{$this->localKey} ? $this->first() : null)
        ?? $this->getDefaultFor($this->farParent);
}

[macropay-solutions]

Laravel 12 has it already.

[de-lazurenko]

Despite being in L12, HasOneThrough still lacks the null-check that HasManyThrough has.

HasManyThrough returns an empty collection immediately if the key is null. HasOneThrough blindly calls $this->first(), which triggers a redundant SELECT ... LIMIT 1 query that will never find a match.

public function getResults()
{
    return $this->first() ?: $this->getDefaultFor($this->farParent);
}

It should be unified with the parent logic to prevent this DB hit.

[macropay-solutions]

Look here c5f2a94