Fix: Unable to refresh a collection containing mixed types

src/SingleInheritanceBuilderTrait.php

@@ -0,0 +1,52 @@
+<?php
+
+namespace Nanigans\SingleTableInheritance;
+
+use Illuminate\Database\Eloquent\Builder as EloquentBuilder;
+use Illuminate\Database\Eloquent\Model;
+use Nanigans\SingleTableInheritance\Contracts\SingleTableInheritanceBuilder;
+
+trait SingleInheritanceBuilderTrait
+{
+    /**
+     * Returns a fresh instance of the model at the root of the inheritance-tree as defined by
+     * the Builder's `singleInheritanceRootModelClass` property.
+     * @return Model
+     */
+    protected function newSingleInheritanceRootModel(): Model
+    {
+        $property = 'singleInheritanceRootModelClass';
+        if (!property_exists($this, $property)) {
+            throw new \RuntimeException(sprintf(
+                '%s must declare a string property named %s',
+                get_called_class(),
+                $property
+            ));
+        }
+
+        $className = $this->$property;
+        return new $className();
+    }
+
+    /**
+     * This makes it so that polymorphic collections can be constructed properly.
+     *
+     * @param  array|string  $columns
+     * @return Model[]|static[]
+     */
+    public function getModels($columns = ['*'])
+    {
+        /*
+         * The problem stems from Laravel using the first element in the collection to hydrate the rest of the records
+         * into Eloquent models. Thus, if any of the subsequent records do is of a type that does not inherit
+         * from that of the first element, then it fails.
+         *
+         * If we use an instance of the root model of the
+         * inheritance tree, then we can properly hydrate records into polymorphic models.
+         */
+        $rootModel = $this->newSingleInheritanceRootModel();
+        return $rootModel->hydrate(
+            $this->query->get($columns)->all()
+        )->all();
+    }
+}

tests/Fixtures/Vehicle.php

@@ -66,4 +66,9 @@ public function setPrimaryKey($primaryKey) {
   public function setTable($table) {
     $this->table = $table;
   }
-}
+
+  public function newEloquentBuilder($query)
+  {
+      return new VehicleBuilder($query);
+  }
+}

tests/Fixtures/VehicleBuilder.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace Nanigans\SingleTableInheritance\Tests\Fixtures;
+
+use Illuminate\Database\Eloquent\Builder;
+use Nanigans\SingleTableInheritance\SingleInheritanceBuilderTrait;
+
+class VehicleBuilder extends Builder
+{
+   use SingleInheritanceBuilderTrait;
+
+   protected $singleInheritanceRootModelClass = Vehicle::class;
+}

tests/SingleTableInheritanceTraitCollectionTest.php

@@ -0,0 +1,49 @@
+<?php
+
+namespace Nanigans\SingleTableInheritance\Tests;
+
+use Carbon\Carbon;
+use Illuminate\Support\Facades\DB;
+use Nanigans\SingleTableInheritance\Exceptions\SingleTableInheritanceException;
+use Nanigans\SingleTableInheritance\Tests\Fixtures\User;
+use Nanigans\SingleTableInheritance\Tests\Fixtures\Bike;
+use Nanigans\SingleTableInheritance\Tests\Fixtures\Car;
+use Nanigans\SingleTableInheritance\Tests\Fixtures\MotorVehicle;
+use Nanigans\SingleTableInheritance\Tests\Fixtures\Truck;
+use Nanigans\SingleTableInheritance\Tests\Fixtures\Vehicle;
+
+/**
+ * Class SingleTableInheritanceTraitQueryTest
+ *
+ * A set of tests for the behavior of Eloquent collections that are polymorphic.
+ *
+ * @package Nanigans\SingleTableInheritance\Tests
+ */
+class SingleTableInheritanceTraitCollectionTest extends TestCase {
+
+  public function testRefresh() {
+    (new MotorVehicle())->save();
+    (new Car())->save();
+    (new Truck())->save();
+    (new Truck())->save();
+    (new Bike())->save();
+
+    $results = Vehicle::all();
+
+    $this->assertEquals(5, count($results));
+
+    $this->assertInstanceOf('Nanigans\SingleTableInheritance\Tests\Fixtures\MotorVehicle', $results[0]);
+    $this->assertInstanceOf('Nanigans\SingleTableInheritance\Tests\Fixtures\Car',          $results[1]);
+    $this->assertInstanceOf('Nanigans\SingleTableInheritance\Tests\Fixtures\Truck',        $results[2]);
+    $this->assertInstanceOf('Nanigans\SingleTableInheritance\Tests\Fixtures\Truck',        $results[3]);
+    $this->assertInstanceOf('Nanigans\SingleTableInheritance\Tests\Fixtures\Bike',         $results[4]);
+
+    $results = $results->fresh();
+
+    $this->assertInstanceOf('Nanigans\SingleTableInheritance\Tests\Fixtures\MotorVehicle', $results[0]);
+    $this->assertInstanceOf('Nanigans\SingleTableInheritance\Tests\Fixtures\Car',          $results[1]);
+    $this->assertInstanceOf('Nanigans\SingleTableInheritance\Tests\Fixtures\Truck',        $results[2]);
+    $this->assertInstanceOf('Nanigans\SingleTableInheritance\Tests\Fixtures\Truck',        $results[3]);
+    $this->assertInstanceOf('Nanigans\SingleTableInheritance\Tests\Fixtures\Bike',         $results[4]);
+  }
+}