MDL-58220 oauth2: Use the same list of user fields

Authentication has a hard coded list of valid internal user fields - but they are in a class variable. We need them
in oauth user_field_mapping so we need to move them to a central place and call them from oauth2 and auth.

lib/authlib.php

@@ -102,26 +102,7 @@ class auth_plugin_base {
      * The fields we can lock and update from/to external authentication backends
      * @var array
      */
-    var $userfields = array(
-        'firstname',
-        'lastname',
-        'email',
-        'city',
-        'country',
-        'lang',
-        'description',
-        'url',
-        'idnumber',
-        'institution',
-        'department',
-        'phone1',
-        'phone2',
-        'address',
-        'firstnamephonetic',
-        'lastnamephonetic',
-        'middlename',
-        'alternatename'
-    );
+    var $userfields = \core_user::AUTHSYNCFIELDS;
 
     /**
      * Moodle custom fields to sync with.

lib/classes/oauth2/user_field_mapping.php

@@ -37,21 +37,14 @@ class user_field_mapping extends persistent {
 
     const TABLE = 'oauth2_user_field_mapping';
 
-    /** @var array $userfields - List of standard Moodle userfields. */
-    private static $userfields = [
-        'firstname',
-        'middlename',
-        'lastname',
-        'email',
-        'username',
-        'idnumber',
-        'url',
-        'alternatename',
-        'picture',
-        'address',
-        'phone',
-        'lang'
-    ];
+    /**
+     * Return the list of valid internal user fields.
+     *
+     * @return array
+     */
+    private static function get_user_fields() {
+        return array_merge(\core_user::AUTHSYNCFIELDS, ['picture']);
+    }
 
     /**
      * Return the definition of the properties of this model.
@@ -68,7 +61,7 @@ class user_field_mapping extends persistent {
             ),
             'internalfield' => array(
                 'type' => PARAM_ALPHANUMEXT,
-                'choices' => self::$userfields,
+                'choices' => self::get_user_fields()
             )
         );
     }
@@ -79,6 +72,6 @@ class user_field_mapping extends persistent {
      * @return array
      */
     public function get_internalfield_list() {
-        return array_combine(self::$userfields, self::$userfields);
+        return array_combine(self::get_user_fields(), self::get_user_fields());
     }
 }

lib/classes/user.php

@@ -58,6 +58,30 @@ class core_user {
      */
     const MAILDISPLAY_COURSE_MEMBERS_ONLY = 2;
 
+    /**
+     * List of fields that can be synched/locked during authentication.
+     */
+    const AUTHSYNCFIELDS = [
+        'firstname',
+        'lastname',
+        'email',
+        'city',
+        'country',
+        'lang',
+        'description',
+        'url',
+        'idnumber',
+        'institution',
+        'department',
+        'phone1',
+        'phone2',
+        'address',
+        'firstnamephonetic',
+        'lastnamephonetic',
+        'middlename',
+        'alternatename'
+    ];
+
     /** @var stdClass keep record of noreply user */
     public static $noreplyuser = false;
 
@@ -887,4 +911,5 @@ class core_user {
             return $value;
         }
     }
+
 }