From be7dccca9f9249c928108d957fe70e78d370d26e Mon Sep 17 00:00:00 2001
From: Taylor Otwell <taylor@laravel.com>
Date: Fri, 29 Sep 2017 13:57:02 -0500
Subject: [PATCH] add interface

---
 .../Http/Resources/ConditionallyLoadsAttributes.php |  5 +++--
 src/Illuminate/Http/Resources/MissingValue.php      | 12 ++++++++++--
 .../Http/Resources/PotentiallyMissing.php           | 13 +++++++++++++
 3 files changed, 26 insertions(+), 4 deletions(-)
 create mode 100644 src/Illuminate/Http/Resources/PotentiallyMissing.php

diff --git a/src/Illuminate/Http/Resources/ConditionallyLoadsAttributes.php b/src/Illuminate/Http/Resources/ConditionallyLoadsAttributes.php
index ab962bd535cc..1662fa1947b1 100644
--- a/src/Illuminate/Http/Resources/ConditionallyLoadsAttributes.php
+++ b/src/Illuminate/Http/Resources/ConditionallyLoadsAttributes.php
@@ -29,9 +29,10 @@ protected function filter($data)
                 return $this->merge($data, $index, $this->filter($value->data));
             }
 
-            if ($value instanceof MissingValue ||
+            if (($value instanceof PotentiallyMissing && $value->isMissing()) ||
                 ($value instanceof self &&
-                $value->resource instanceof MissingValue)) {
+                $value->resource instanceof PotentiallyMissing &&
+                $value->isMissing())) {
                 unset($data[$key]);
 
                 $index--;
diff --git a/src/Illuminate/Http/Resources/MissingValue.php b/src/Illuminate/Http/Resources/MissingValue.php
index 4bd1eff4d2a2..d0d8dfa78914 100644
--- a/src/Illuminate/Http/Resources/MissingValue.php
+++ b/src/Illuminate/Http/Resources/MissingValue.php
@@ -2,7 +2,15 @@
 
 namespace Illuminate\Http\Resources;
 
-class MissingValue
+class MissingValue implements PotentiallyMissing
 {
-    //
+    /**
+     * Determine if the object should be considered "missing".
+     *
+     * @return bool
+     */
+    public function isMissing()
+    {
+        return true;
+    }
 }
diff --git a/src/Illuminate/Http/Resources/PotentiallyMissing.php b/src/Illuminate/Http/Resources/PotentiallyMissing.php
new file mode 100644
index 000000000000..6ed7f3c8b86c
--- /dev/null
+++ b/src/Illuminate/Http/Resources/PotentiallyMissing.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace Illuminate\Http\Resources;
+
+interface PotentiallyMissing
+{
+    /**
+     * Determine if the object should be considered "missing".
+     *
+     * @return bool
+     */
+    public function isMissing();
+}