includes/debug/DeprecationHelper.php

   1 <?php
   2 /**
   3  * Trait for issuing warnings on deprecated access.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22
  23 /**
  24  * Use this trait in classes which have properties for which public access
  25  * is deprecated. Set the list of properties in $deprecatedPublicProperties
  26  * and make the properties non-public. The trait will preserve public access
  27  * but issue deprecation warnings when it is needed.
  28  *
  29  * Example usage:
  30  *     class Foo {
  31  *         use DeprecationHelper;
  32  *         protected $bar;
  33  *         public function __construct() {
  34  *             $this->deprecatePublicProperty( 'bar', '1.21', __CLASS__ );
  35  *         }
  36  *     }
  37  *
  38  *     $foo = new Foo;
  39  *     $foo->bar; // works but logs a warning
  40  *
  41  * Cannot be used with classes that have their own __get/__set methods.
  42  *
  43  * @since 1.32
  44  */
  45 trait DeprecationHelper {
  46
  47         /**
  48          * List of deprecated properties, in <property name> => [<version>, <class>, <component>] format
  49          * where <version> is the MediaWiki version where the property got deprecated, <class> is the
  50          * the name of the class defining the property, <component> is the MediaWiki component
  51          * (extension, skin etc.) for use in the deprecation warning) or null if it is MediaWiki.
  52          * E.g. [ 'mNewRev' => [ '1.32', 'DifferenceEngine', null ]
  53          * @var string[][]
  54          */
  55         protected $deprecatedPublicProperties = [];
  56
  57         /**
  58          * Mark a property as deprecated. Only use this for properties that used to be public and only
  59          *   call it in the constructor.
  60          * @param string $property The name of the property.
  61          * @param string $version MediaWiki version where the property became deprecated.
  62          * @param string|null $class The class which has the deprecated property. This can usually be
  63          *   guessed, but PHP can get confused when both the parent class and the subclass use the
  64          *   trait, so it should be specified in classes meant for subclassing.
  65          * @param string|null $component
  66          * @see wfDeprecated()
  67          */
  68         protected function deprecatePublicProperty(
  69                 $property, $version, $class = null, $component = null
  70         ) {
  71                 $this->deprecatedPublicProperties[$property] = [ $version, $class ?: __CLASS__, $component ];
  72         }
  73
  74         public function __get( $name ) {
  75                 if ( isset( $this->deprecatedPublicProperties[$name] ) ) {
  76                         list( $version, $class, $component ) = $this->deprecatedPublicProperties[$name];
  77                         $qualifiedName = $class . '::$' . $name;
  78                         wfDeprecated( $qualifiedName, $version, $component, 3 );
  79                         return $this->$name;
  80                 }
  81
  82                 $ownerClass = $this->deprecationHelperGetPropertyOwner( $name );
  83                 $qualifiedName = ( $ownerClass ?: get_class( $this ) ) . '::$' . $name;
  84                 if ( $ownerClass ) {
  85                         // Someone tried to access a normal non-public property. Try to behave like PHP would.
  86                         trigger_error( "Cannot access non-public property $qualifiedName", E_USER_ERROR );
  87                 } else {
  88                         // Non-existing property. Try to behave like PHP would.
  89                         trigger_error( "Undefined property: $qualifiedName", E_USER_NOTICE );
  90                 }
  91                 return null;
  92         }
  93
  94         public function __set( $name, $value ) {
  95                 if ( isset( $this->deprecatedPublicProperties[$name] ) ) {
  96                         list( $version, $class, $component ) = $this->deprecatedPublicProperties[$name];
  97                         $qualifiedName = $class . '::$' . $name;
  98                         wfDeprecated( $qualifiedName, $version, $component, 3 );
  99                         $this->$name = $value;
 100                         return;
 101                 }
 102
 103                 $ownerClass = $this->deprecationHelperGetPropertyOwner( $name );
 104                 $qualifiedName = ( $ownerClass ?: get_class( $this ) ) . '::$' . $name;
 105                 if ( $ownerClass ) {
 106                         // Someone tried to access a normal non-public property. Try to behave like PHP would.
 107                         trigger_error( "Cannot access non-public property $qualifiedName", E_USER_ERROR );
 108                 } else {
 109                         // Non-existing property. Try to behave like PHP would.
 110                         $this->$name = $value;
 111                 }
 112         }
 113
 114         /**
 115          * Like property_exists but also check for non-visible private properties and returns which
 116          * class in the inheritance chain declared the property.
 117          * @param string $property
 118          * @return string|bool Best guess for the class in which the property is defined. False if
 119          *   the object does not have such a property.
 120          */
 121         private function deprecationHelperGetPropertyOwner( $property ) {
 122                 // Returning false is a non-error path and should avoid slow checks like reflection.
 123                 // Use array cast hack instead.
 124                 $obfuscatedProps = array_keys( (array)$this );
 125                 $obfuscatedPropTail = "\0$property";
 126                 foreach ( $obfuscatedProps as $obfuscatedProp ) {
 127                         // private props are in the form \0<classname>\0<propname>
 128                         if ( strpos( $obfuscatedProp, $obfuscatedPropTail, 1 ) !== false ) {
 129                                 $classname = substr( $obfuscatedProp, 1, -strlen( $obfuscatedPropTail ) );
 130                                 if ( $classname === '*' ) {
 131                                         // protected property; we didn't get the name, but we are on an error path
 132                                         // now so it's fine to use reflection
 133                                         return ( new ReflectionProperty( $this, $property ) )->getDeclaringClass()->getName();
 134                                 }
 135                                 return $classname;
 136                         }
 137                 }
 138                 return false;
 139         }
 140
 141 }