Allow callables for config

Author: stancl

README.md

@@ -126,3 +126,31 @@ class Parent extends Model
     }
 }
 ```
+
+You may also pass a callable as the config value. This is useful if you want to disable this behavior on some requests. See example below.
+
+## Laravel Nova
+
+It's a good idea to disable setting the relationship on resolution for Nova requests. They tend to make a lot of queries and this can slow the page down (or result in 502 errors).
+
+Here's an example implementation using a base model and adding config to filter out Nova requests.
+
+```php
+abstract class Model extends EloquentModel
+{
+    use HasManyWithInverse {
+        hasManyWithInverse as originalHasManyWithInverse;
+    }
+
+    public function hasManyWithInverse($related, $inverse, $foreignKey = null, $localKey = null, $config = [])
+    {
+        $config = array_merge(['setRelationOnResolution' => function () {
+            if (request()->route() && in_array('nova', request()->route()->middleware())) {
+                return false;
+            }
+        }], $config);
+
+        return $this->originalHasManyWithInverse($related, $inverse, $foreignKey, $localKey, $config);
+    }
+}
+```

src/HasManyWithInverseRelationship.php

@@ -32,7 +32,7 @@ public function create(array $attributes = [])
         return tap($this->related->newInstance($attributes), function ($instance) {
             $this->setForeignAttributesForCreate($instance);
 
-            if ($this->config['setRelationOnCreation'] ?? true) {
+            if ($this->config('setRelationOnCreation', true)) {
                 $instance->setRelation($this->relationToParent, $this->getParent());
             }
 
@@ -44,11 +44,23 @@ public function getResults()
     {
         $results = parent::getResults();
 
-        if ($this->config['setRelationOnResolution'] ?? true) {
+        if ($this->config('setRelationOnResolution', true)) {
             $results->each->setRelation($this->relationToParent, $this->getParent());
         }
 
         return $results;
     }
+
+    protected function config(string $key, $default)
+    {
+        if (! isset($this->config[$key])) {
+            return $default;
+        }
+
+        if (is_callable($this->config[$key])) {
+            return $this->config[$key]();
+        }
+
+        return $this->config[$key];
+    }
 }
- 

tests/ConfigTest.php

@@ -41,4 +41,25 @@ public function children()
 
         $this->assertFalse($parent->children->first()->relationLoaded('parent'));
     }
+
+    /** @test */
+    public function config_value_can_be_a_closure()
+    {
+        /** @var ParentModel $parent */
+        $parent = (new class extends ParentModel {
+            public function children()
+            {
+                return $this->hasManyWithInverse(ChildModel::class, 'parent', 'parent_id', null, [
+                    'setRelationOnResolution' => function () {
+                        return false;
+                    },
+                ]);
+            }
+        })::create([]);
+
+        /** @var ChildModel $child */
+        $child = $parent->children()->create([]);
+
+        $this->assertFalse($parent->children->first()->relationLoaded('parent'));
+    }
 }