Hydrator: Don't spill properly qualified relation cols onto base model

fixes #123

src/Hydrator.php

@@ -109,6 +109,7 @@ protected function updateColumnToTargetMap(string $path, array $columnToProperty
     public function hydrate(array $data, Model $model)
     {
         $defaultsToApply = [];
+        $columnToTargetMap = $this->columnToTargetMap;
         foreach ($this->hydrators as $path => $vars) {
             list($target, $relation, $columnToPropertyMap, $defaults) = $vars;
 
@@ -143,7 +144,7 @@ public function hydrate(array $data, Model $model)
                 }
             }
 
-            $subject->setProperties($this->extractAndMap($data, $columnToPropertyMap, $path));
+            $subject->setProperties($this->extractAndMap($data, $columnToPropertyMap, $path, $columnToTargetMap));
             $this->query->getResolver()->getBehaviors($target)->retrieve($subject);
             $defaultsToApply[] = [$subject, $defaults];
         }
@@ -205,20 +206,21 @@ public function hydrate(array $data, Model $model)
      * @param array $data
      * @param array $columnToPropertyMap
      * @param string $path
+     * @param array $columnToTargetMap
      *
      * @return array
      */
-    protected function extractAndMap(array &$data, array $columnToPropertyMap, string $path)
+    protected function extractAndMap(array &$data, array $columnToPropertyMap, string $path, array &$columnToTargetMap)
     {
         $extracted = [];
         foreach (array_intersect_key($columnToPropertyMap, $data) as $column => $property) {
             $extracted[$property] = $data[$column];
 
-            if (isset($this->columnToTargetMap[$column][$path])) {
-                unset($this->columnToTargetMap[$column][$path]);
-                if (empty($this->columnToTargetMap[$column])) {
+            if (isset($columnToTargetMap[$column][$path])) {
+                unset($columnToTargetMap[$column][$path]);
+                if (empty($columnToTargetMap[$column])) {
                     // Only unset a column once it's really not required anymore
-                    unset($data[$column], $this->columnToTargetMap[$column]);
+                    unset($data[$column], $columnToTargetMap[$column]);
                 }
             }
         }

tests/HydratorTest.php

@@ -17,9 +17,33 @@ public function testWhetherAmbiguousColumnsAreCorrectlyMapped(): void
         $hydrator->hydrate(['subsystem_audit_user_id' => 2], $subject);
 
         $this->assertTrue(isset($subject->audit->user_id), 'Ambiguous columns are not mapped correctly');
-        $this->assertSame($subject->audit->user_id, 2, 'Ambiguous columns are not mapped correctly');
+        $this->assertSame(2, $subject->audit->user_id, 'Ambiguous columns are not mapped correctly');
 
         $this->assertTrue(isset($subject->audit->user->id), 'Ambiguous columns are not mapped correctly');
-        $this->assertSame($subject->audit->user->id, 2, 'Ambiguous columns are not mapped correctly');
+        $this->assertSame(2, $subject->audit->user->id, 'Ambiguous columns are not mapped correctly');
+    }
+
+    public function testWhetherProperlyQualifiedColumnsAreOnlyPassedOnToMatchingTargets()
+    {
+        $query = Car::on(new TestConnection())
+            ->with('user_custom_keys');
+
+        $hydrator = $query->createHydrator();
+
+        $subject = new Car();
+        $hydrator->hydrate(['car_user_custom_keys_username' => 'foo'], $subject);
+
+        $subject2 = new Car();
+        $hydrator->hydrate(['car_user_custom_keys_username' => 'bar'], $subject2);
+
+        $this->assertFalse(
+            isset($subject->user->custom_keys_username),
+            'This should not fail. If it does, there is a new issue'
+        );
+
+        $this->assertFalse(
+            isset($subject2->user->custom_keys_username),
+            'Properly qualified relation columns are spilled onto the base model'
+        );
     }
 }