MDL-50704 user: Do not validate timezones in user objects

The validation of the timezone field should not occur, especially
when it is automatically cleaned. Timezones can be volatile, we
must try hard to fallback on real timezones and must not lose reset
the values arbitrarily.

"There is absolutely no need to change $CFG->timezone and user timezones
in database - the timezones may come and go. If you change the value in
upgrade or on the fly you would not be able to get it back. This is the
reason why I implemented the "invalid timezone" thing in server and
user settings instead." - Petr Skoda (MDL-49684)

lib/classes/user.php

@@ -337,8 +337,8 @@ protected static function fill_properties_cache() {
                 'choices' => array_merge(array('' => ''), \core_calendar\type_factory::get_list_of_calendar_types()));
         $fields['theme'] = array('type' => PARAM_THEME, 'null' => NULL_NOT_ALLOWED,
                 'default' => theme_config::DEFAULT_THEME, 'choices' => array_merge(array('' => ''), get_list_of_themes()));
-        $fields['timezone'] = array('type' => PARAM_TIMEZONE, 'null' => NULL_NOT_ALLOWED, 'default' => $CFG->timezone,
-                'choices' => core_date::get_list_of_timezones(null, true));
+        $fields['timezone'] = array('type' => PARAM_TIMEZONE, 'null' => NULL_NOT_ALLOWED,
+                'default' => core_date::get_server_timezone()); // Must not use choices here: timezones can come and go.
         $fields['firstaccess'] = array('type' => PARAM_INT, 'null' => NULL_NOT_ALLOWED);
         $fields['lastaccess'] = array('type' => PARAM_INT, 'null' => NULL_NOT_ALLOWED);
         $fields['lastlogin'] = array('type' => PARAM_INT, 'null' => NULL_NOT_ALLOWED);
@@ -528,7 +528,7 @@ public static function get_property_null($property) {
      * Get the choices of the property.
      *
      * This is a helper method to validate a value against a list of acceptable choices.
-     * For instance: country, timezone, language, themes and etc.
+     * For instance: country, language, themes and etc.
      *
      * @param string $property property name to be retrieved.
      * @throws coding_exception if the requested property name is invalid or if it does not has a list of choices.

lib/tests/user_test.php

@@ -363,15 +363,6 @@ public function test_get_property_choices() {
         $this->assertArrayNotHasKey('unknowntheme', $choices);
         $this->assertArrayNotHasKey('wrongtheme', $choices);
 
-        // Test against timezone property choices.
-        $choices = core_user::get_property_choices('timezone');
-        $this->assertArrayHasKey('America/Sao_Paulo', $choices);
-        $this->assertArrayHasKey('Australia/Perth', $choices);
-        $this->assertArrayHasKey('99', $choices);
-        $this->assertArrayHasKey('UTC', $choices);
-        $this->assertArrayNotHasKey('North Korea', $choices);
-        $this->assertArrayNotHasKey('New york', $choices);
-
         // Try to fetch type of a non-existent properties.
         $nonexistingproperty = 'language';
         $this->setExpectedException('coding_exception', 'Invalid property requested: ' . $nonexistingproperty);
@@ -386,6 +377,7 @@ public function test_get_property_choices() {
      */
     public function test_get_property_default() {
         global $CFG;
+        $this->resetAfterTest();
 
         $country = core_user::get_property_default('country');
         $this->assertEquals($CFG->country, $country);
@@ -400,12 +392,14 @@ public function test_get_property_default() {
         $lang = core_user::get_property_default('lang');
         $this->assertEquals($CFG->lang, $lang);
 
+        $this->setTimezone('Europe/London', 'Pacific/Auckland');
+        core_user::reset_caches();
         $timezone = core_user::get_property_default('timezone');
-        $this->assertEquals($CFG->timezone, $timezone);
-        set_config('timezone', 99);
+        $this->assertEquals('Europe/London', $timezone);
+        $this->setTimezone('99', 'Pacific/Auckland');
         core_user::reset_caches();
         $timezone = core_user::get_property_default('timezone');
-        $this->assertEquals(99, $timezone);
+        $this->assertEquals('Pacific/Auckland', $timezone);
 
         $this->setExpectedException('coding_exception', 'Invalid property requested, or the property does not has a default value.');
         core_user::get_property_default('firstname');

user/tests/userlib_test.php

@@ -99,7 +99,7 @@ public function test_user_update_user() {
         $user->country = 'WW';
         $user->lang = 'xy';
         $user->theme = 'somewrongthemename';
-        $user->timezone = 'Paris';
+        $user->timezone = '30.5';
         $user->url = 'wwww.somewrong@#$url.com.aus';
         $debugmessages = $this->getDebuggingMessages();
         user_update_user($user, true, false);
@@ -182,15 +182,15 @@ public function test_create_users() {
         $user['country'] = 'WW';
         $user['lang'] = 'xy';
         $user['theme'] = 'somewrongthemename';
-        $user['timezone'] = 'Paris';
+        $user['timezone'] = '-30.5';
         $user['url'] = 'wwww.somewrong@#$url.com.aus';
         $debugmessages = $this->getDebuggingMessages();
         $user['id'] = user_create_user($user, true, false);
         $this->assertDebuggingCalledCount(6, $debugmessages);
         $dbuser = $DB->get_record('user', array('id' => $user['id']));
         $this->assertEquals($dbuser->country, 0);
         $this->assertEquals($dbuser->lang, 'en');
-        $this->assertEquals($dbuser->timezone, 'Australia/Perth');
+        $this->assertEquals($dbuser->timezone, '');
 
         // Now, with valid user data.
         $user['username'] = 'johndoe321';