[9.x] Address Dynamic Relation Resolver inconsiency issue with extended Models (#45122)

* #44741 - Address Dynamic Relation Resolver inconsistency issue with extended Models

* style fixes

Author: vmcvlad

src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php

@@ -541,7 +541,7 @@ public function isRelation($key)
         }
 
         return method_exists($this, $key) ||
-            (static::$relationResolvers[get_class($this)][$key] ?? null);
+               $this->relationResolver(static::class, $key);
     }
 
     /**

src/Illuminate/Database/Eloquent/Concerns/HasRelationships.php

@@ -54,6 +54,26 @@ trait HasRelationships
      */
     protected static $relationResolvers = [];
 
+    /**
+     * Get the dynamic relation resolver if defined or inherited, or return null.
+     *
+     * @param  string  $class
+     * @param  string  $key
+     * @return mixed
+     */
+    public function relationResolver($class, $key)
+    {
+        if ($resolver = static::$relationResolvers[$class][$key] ?? null) {
+            return $resolver;
+        }
+
+        if ($parent = get_parent_class($class)) {
+            return $this->relationResolver($parent, $key);
+        }
+
+        return null;
+    }
+
     /**
      * Define a dynamic relation resolver.
      *

src/Illuminate/Database/Eloquent/Model.php

@@ -2314,7 +2314,7 @@ public function __call($method, $parameters)
             return $this->$method(...$parameters);
         }
 
-        if ($resolver = (static::$relationResolvers[get_class($this)][$method] ?? null)) {
+        if ($resolver = ($this->relationResolver(static::class, $method))) {
             return $resolver($this);
         }
 

tests/Database/DatabaseEloquentBelongsToManyWithCastedAttributesTest.php

@@ -25,15 +25,15 @@ public function testModelsAreProperlyMatchedToParents()
         $model1->shouldReceive('hasGetMutator')->andReturn(false);
         $model1->shouldReceive('hasAttributeMutator')->andReturn(false);
         $model1->shouldReceive('getCasts')->andReturn([]);
-        $model1->shouldReceive('getRelationValue', 'relationLoaded', 'setRelation', 'isRelation')->passthru();
+        $model1->shouldReceive('getRelationValue', 'relationLoaded', 'relationResolver', 'setRelation', 'isRelation')->passthru();
 
         $model2 = m::mock(Model::class);
         $model2->shouldReceive('getAttribute')->with('parent_key')->andReturn(2);
         $model2->shouldReceive('getAttribute')->with('foo')->passthru();
         $model2->shouldReceive('hasGetMutator')->andReturn(false);
         $model2->shouldReceive('hasAttributeMutator')->andReturn(false);
         $model2->shouldReceive('getCasts')->andReturn([]);
-        $model2->shouldReceive('getRelationValue', 'relationLoaded', 'setRelation', 'isRelation')->passthru();
+        $model2->shouldReceive('getRelationValue', 'relationLoaded', 'relationResolver', 'setRelation', 'isRelation')->passthru();
 
         $result1 = (object) [
             'pivot' => (object) [

tests/Database/DatabaseEloquentDynamicRelationsTest.php

@@ -20,7 +20,7 @@ public function testBasicDynamicRelations()
         $this->assertEquals(['many' => 'related'], $model->getRelationValue('dynamicRel_2'));
     }
 
-    public function testDynamicRelationsOverride()
+    public function testBasicDynamicRelationsOverride()
     {
         // Dynamic Relations can override each other.
         DynamicRelationModel::resolveRelationUsing('dynamicRelConflict', fn ($m) => $m->hasOne(Related::class));
@@ -33,6 +33,32 @@ public function testDynamicRelationsOverride()
         $this->assertTrue($model->isRelation('dynamicRelConflict'));
     }
 
+    public function testInharitedDynamicRelations()
+    {
+        DynamicRelationModel::resolveRelationUsing('inheritedDynamicRel', fn () => new FakeHasManyRel);
+        $model = new DynamicRelationModel;
+        $model2 = new DynamicRelationModel2;
+        $model4 = new DynamicRelationModel4;
+        $this->assertTrue($model->isRelation('inheritedDynamicRel'));
+        $this->assertTrue($model4->isRelation('inheritedDynamicRel'));
+        $this->assertFalse($model2->isRelation('inheritedDynamicRel'));
+        $this->assertEquals($model->inheritedDynamicRel(), $model4->inheritedDynamicRel());
+        $this->assertEquals($model->inheritedDynamicRel, $model4->inheritedDynamicRel);
+    }
+
+    public function testInheritedDynamicRelationsOverride()
+    {
+        // Inherited Dynamic Relations can be overriden
+        DynamicRelationModel::resolveRelationUsing('dynamicRelConflict', fn ($m) => $m->hasOne(Related::class));
+        $model = new DynamicRelationModel;
+        $model4 = new DynamicRelationModel4;
+        $this->assertInstanceOf(HasOne::class, $model->dynamicRelConflict());
+        $this->assertInstanceOf(HasOne::class, $model4->dynamicRelConflict());
+        DynamicRelationModel4::resolveRelationUsing('dynamicRelConflict', fn ($m) => $m->hasMany(Related::class));
+        $this->assertInstanceOf(HasOne::class, $model->dynamicRelConflict());
+        $this->assertInstanceOf(HasMany::class, $model4->dynamicRelConflict());
+    }
+
     public function testDynamicRelationsCanNotHaveTheSameNameAsNormalRelations()
     {
         $model = new DynamicRelationModel;
@@ -94,6 +120,11 @@ class DynamicRelationModel3 extends Model
     //
 }
 
+class DynamicRelationModel4 extends DynamicRelationModel
+{
+    //
+}
+
 class FakeHasManyRel extends HasMany
 {
     public function __construct()