From 6cd61dab8be9514ff47c9f8f7cccd6e841c31945 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michael=20Vo=C5=99=C3=AD=C5=A1ek?= <mvorisek@mvorisek.cz>
Date: Mon, 4 Oct 2021 12:27:58 +0200
Subject: [PATCH] Warn if property does not exist and add it to
 DiContainerTrait (#329)

---
 src/DiContainerTrait.php         |  2 ++
 src/Exception.php                |  2 ++
 src/WarnDynamicPropertyTrait.php | 51 ++++++++++++++++++++++++++++++++
 3 files changed, 55 insertions(+)
 create mode 100644 src/WarnDynamicPropertyTrait.php

diff --git a/src/DiContainerTrait.php b/src/DiContainerTrait.php
index 72c236bf..0b74808a 100644
--- a/src/DiContainerTrait.php
+++ b/src/DiContainerTrait.php
@@ -32,6 +32,8 @@
  */
 trait DiContainerTrait
 {
+    use WarnDynamicPropertyTrait;
+
     /**
      * Call from __construct() to initialize the properties allowing
      * developer to pass Dependency Injector Container.
diff --git a/src/Exception.php b/src/Exception.php
index 32de802f..e8a4fd1e 100644
--- a/src/Exception.php
+++ b/src/Exception.php
@@ -11,6 +11,8 @@
  */
 class Exception extends \Exception
 {
+    use WarnDynamicPropertyTrait;
+
     /** @var array */
     public $params = [];
 
diff --git a/src/WarnDynamicPropertyTrait.php b/src/WarnDynamicPropertyTrait.php
new file mode 100644
index 00000000..12effcd6
--- /dev/null
+++ b/src/WarnDynamicPropertyTrait.php
@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Atk4\Core;
+
+/**
+ * This trait implements https://github.com/php/php-src/pull/7390 for lower PHP versions
+ * and also emit a warning when isset() is called on undefined variable.
+ */
+trait WarnDynamicPropertyTrait
+{
+    protected function warnPropertyDoesNotExist(string $name): void
+    {
+        'trigger_error'('Property ' . static::class . '::$' . $name . ' does not exist', \E_USER_DEPRECATED);
+    }
+
+    public function __isset(string $name): bool
+    {
+        $this->warnPropertyDoesNotExist($name);
+
+        return isset($this->{$name});
+    }
+
+    /**
+     * @return mixed
+     */
+    public function &__get(string $name)
+    {
+        $this->warnPropertyDoesNotExist($name);
+
+        return $this->{$name};
+    }
+
+    /**
+     * @param mixed $value
+     */
+    public function __set(string $name, $value): void
+    {
+        $this->warnPropertyDoesNotExist($name);
+
+        $this->{$name} = $value;
+    }
+
+    public function __unset(string $name): void
+    {
+        $this->warnPropertyDoesNotExist($name);
+
+        unset($this->{$name});
+    }
+}