1 files changed, 134 insertions, 0 deletions
diff --git a/platform/www/inc/Debug/PropertyDeprecationHelper.php b/platform/www/inc/Debug/PropertyDeprecationHelper.php
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+++ b/platform/www/inc/Debug/PropertyDeprecationHelper.php
@@ -0,0 +1,134 @@
+<?php
+/**
+ * Trait for issuing warnings on deprecated access.
+ *
+ * Adapted from https://github.com/wikimedia/mediawiki/blob/4aedefdbfd193f323097354bf581de1c93f02715/includes/debug/DeprecationHelper.php
+ *
+ */
+
+
+namespace dokuwiki\Debug;
+
+/**
+ * Use this trait in classes which have properties for which public access
+ * is deprecated. Set the list of properties in $deprecatedPublicProperties
+ * and make the properties non-public. The trait will preserve public access
+ * but issue deprecation warnings when it is needed.
+ *
+ * Example usage:
+ *     class Foo {
+ *         use DeprecationHelper;
+ *         protected $bar;
+ *         public function __construct() {
+ *             $this->deprecatePublicProperty( 'bar', '1.21', __CLASS__ );
+ *         }
+ *     }
+ *
+ *     $foo = new Foo;
+ *     $foo->bar; // works but logs a warning
+ *
+ * Cannot be used with classes that have their own __get/__set methods.
+ *
+ */
+trait PropertyDeprecationHelper
+{
+
+    /**
+     * List of deprecated properties, in <property name> => <class> format
+     * where <class> is the the name of the class defining the property
+     *
+     * E.g. [ '_event' => '\dokuwiki\Cache\Cache' ]
+     * @var string[]
+     */
+    protected $deprecatedPublicProperties = [];
+
+    /**
+     * Mark a property as deprecated. Only use this for properties that used to be public and only
+     *   call it in the constructor.
+     *
+     * @param string $property The name of the property.
+     * @param null $class name of the class defining the property
+     * @see DebugHelper::dbgDeprecatedProperty
+     */
+    protected function deprecatePublicProperty(
+        $property,
+        $class = null
+    ) {
+        $this->deprecatedPublicProperties[$property] = $class ?: get_class();
+    }
+
+    public function __get($name)
+    {
+        if (isset($this->deprecatedPublicProperties[$name])) {
+            $class = $this->deprecatedPublicProperties[$name];
+            DebugHelper::dbgDeprecatedProperty($class, $name);
+            return $this->$name;
+        }
+
+        $qualifiedName = get_class() . '::$' . $name;
+        if ($this->deprecationHelperGetPropertyOwner($name)) {
+            // Someone tried to access a normal non-public property. Try to behave like PHP would.
+            trigger_error("Cannot access non-public property $qualifiedName", E_USER_ERROR);
+        } else {
+            // Non-existing property. Try to behave like PHP would.
+            trigger_error("Undefined property: $qualifiedName", E_USER_NOTICE);
+        }
+        return null;
+    }
+
+    public function __set($name, $value)
+    {
+        if (isset($this->deprecatedPublicProperties[$name])) {
+            $class = $this->deprecatedPublicProperties[$name];
+            DebugHelper::dbgDeprecatedProperty($class, $name);
+            $this->$name = $value;
+            return;
+        }
+
+        $qualifiedName = get_class() . '::$' . $name;
+        if ($this->deprecationHelperGetPropertyOwner($name)) {
+            // Someone tried to access a normal non-public property. Try to behave like PHP would.
+            trigger_error("Cannot access non-public property $qualifiedName", E_USER_ERROR);
+        } else {
+            // Non-existing property. Try to behave like PHP would.
+            $this->$name = $value;
+        }
+    }
+
+    /**
+     * Like property_exists but also check for non-visible private properties and returns which
+     * class in the inheritance chain declared the property.
+     * @param string $property
+     * @return string|bool Best guess for the class in which the property is defined.
+     */
+    private function deprecationHelperGetPropertyOwner($property)
+    {
+        // Easy branch: check for protected property / private property of the current class.
+        if (property_exists($this, $property)) {
+            // The class name is not necessarily correct here but getting the correct class
+            // name would be expensive, this will work most of the time and getting it
+            // wrong is not a big deal.
+            return __CLASS__;
+        }
+        // property_exists() returns false when the property does exist but is private (and not
+        // defined by the current class, for some value of "current" that differs slightly
+        // between engines).
+        // Since PHP triggers an error on public access of non-public properties but happily
+        // allows public access to undefined properties, we need to detect this case as well.
+        // Reflection is slow so use array cast hack to check for that:
+        $obfuscatedProps = array_keys((array)$this);
+        $obfuscatedPropTail = "\0$property";
+        foreach ($obfuscatedProps as $obfuscatedProp) {
+            // private props are in the form \0<classname>\0<propname>
+            if (strpos($obfuscatedProp, $obfuscatedPropTail, 1) !== false) {
+                $classname = substr($obfuscatedProp, 1, -strlen($obfuscatedPropTail));
+                if ($classname === '*') {
+                    // sanity; this shouldn't be possible as protected properties were handled earlier
+                    $classname = __CLASS__;
+                }
+                return $classname;
+            }
+        }
+        return false;
+    }
+}