MDL-49684 timezones: rewrite timezone support

This patch replaces all homegrown timezone
stuff with standard PHP date/time code.

The main change is the introduction of core_date
class that returns normalised user and server
timezones. From now on nobody should be using
$CFG->timezone or $user->timezone directly!

Other new features and fixes:
* admins are prompted for timezone during install
* editing of other users is finally fixed
* timezones are displayed in user profile
* new $this->setTimezone() in phpunit
* time locale is now automatically reset in phpunit
* timezone is now automatically reset in phpunit
* phpunit has Australia/Perth as default timezone

admin/cli/install.php

@@ -121,10 +121,11 @@
 chdir(dirname($_SERVER['argv'][0]));
 
 // Servers should define a default timezone in php.ini, but if they don't then make sure something is defined.
-// This is a quick hack.  Ideally we should ask the admin for a value.  See MDL-22625 for more on this.
-if (function_exists('date_default_timezone_set') and function_exists('date_default_timezone_get')) {
-    @date_default_timezone_set(@date_default_timezone_get());
+if (!function_exists('date_default_timezone_set') or !function_exists('date_default_timezone_get')) {
+    fwrite(STDERR, "Timezone functions are not available.\n");
+    exit(1);
 }
+date_default_timezone_set(@date_default_timezone_get());
 
 // make sure PHP errors are displayed - helps with diagnosing of problems
 @error_reporting(E_ALL);

admin/index.php

@@ -521,6 +521,7 @@
     // probably new installation - lets return to frontpage after this step
     // remove settings that we want uninitialised
     unset_config('registerauth');
+    unset_config('timezone'); // Force admin to select timezone!
     redirect('upgradesettings.php?return=site');
 }
 

admin/settings/location.php

@@ -4,11 +4,26 @@
 
     // "locations" settingpage
     $temp = new admin_settingpage('locationsettings', new lang_string('locationsettings', 'admin'));
-    $options = get_list_of_timezones();
-    $options[99] = new lang_string('serverlocaltime');
-    $temp->add(new admin_setting_configselect('timezone', new lang_string('timezone','admin'), new lang_string('configtimezone', 'admin'), 99, $options));
+
+    $current = isset($CFG->timezone) ? $CFG->timezone : null;
+    $options = core_date::get_list_of_timezones($current, false);
+    $default = core_date::get_default_php_timezone();
+    if ($current == 99) {
+        // Do not show 99 unless it is current value, we want to get rid of it over time.
+        $options['99'] = new lang_string('timezonephpdefault', 'core_admin', $default);
+    }
+    if ($default === 'UTC') {
+        // Nobody really wants UTC, so instead default selection to the country that is confused by the UTC the most.
+        $default = 'Europe/London';
+    }
+    $temp->add(new admin_setting_configselect('timezone', new lang_string('timezone', 'admin'),
+        new lang_string('configtimezone', 'admin'), $default, $options));
+
+    $options = core_date::get_list_of_timezones(isset($CFG->forcetimezone) ? $CFG->forcetimezone : null, true);
     $options[99] = new lang_string('timezonenotforced', 'admin');
-    $temp->add(new admin_setting_configselect('forcetimezone', new lang_string('forcetimezone', 'admin'), new lang_string('helpforcetimezone', 'admin'), 99, $options));
+    $temp->add(new admin_setting_configselect('forcetimezone', new lang_string('forcetimezone', 'admin'),
+        new lang_string('helpforcetimezone', 'admin'), 99, $options));
+
     $temp->add(new admin_settings_country_select('country', new lang_string('country', 'admin'), new lang_string('configcountry', 'admin'), 0));
     $temp->add(new admin_setting_configtext('defaultcity', new lang_string('defaultcity', 'admin'), new lang_string('defaultcity_help', 'admin'), ''));
 

admin/settings/users.php

@@ -157,6 +157,7 @@
                        array('description' => new lang_string('description'),
                              'city' => new lang_string('city'),
                              'country' => new lang_string('country'),
+                             'timezone' => new lang_string('timezone'),
                              'webpage' => new lang_string('webpage'),
                              'icqnumber' => new lang_string('icqnumber'),
                              'skypeid' => new lang_string('skypeid'),

admin/timezone.php

@@ -41,11 +41,11 @@
     }
 
     require_once($CFG->dirroot.'/calendar/lib.php');
-    $timezones = get_list_of_timezones();
+    $timezones = core_date::get_list_of_timezones(null, true);
 
     echo '<center><form action="timezone.php" method="post">';
     echo html_writer::label($strusers . ' (' . $strall . '): ', 'menuzone');
-    echo html_writer::select($timezones, "zone", $current, array('99'=>get_string("serverlocaltime")));
+    echo html_writer::select($timezones, "zone", $current);
     echo "<input type=\"hidden\" name=\"sesskey\" value=\"".sesskey()."\" />";
     echo '<input type="submit" value="'.s($strsavechanges).'" />';
     echo "</form></center>";

admin/tool/uploaduser/user_form.php

@@ -255,8 +255,7 @@ function definition () {
         }
         $mform->setAdvanced('country');
 
-        $choices = get_list_of_timezones();
-        $choices['99'] = get_string('serverlocaltime');
+        $choices = core_date::get_list_of_timezones($templateuser->timezone, true);
         $mform->addElement('select', 'timezone', get_string('timezone'), $choices);
         $mform->setDefault('timezone', $templateuser->timezone);
         $mform->setAdvanced('timezone');

availability/condition/date/tests/condition_test.php

@@ -47,13 +47,13 @@ public function setUp() {
      * Tests constructing and using date condition as part of tree.
      */
     public function test_in_tree() {
-        global $SITE, $USER;
+        global $SITE, $USER, $CFG;
         $this->resetAfterTest();
         $this->setAdminUser();
 
         // Set server timezone for test. (Important as otherwise the timezone
         // could be anything - this is modified by other unit tests, too.)
-        date_default_timezone_set('UTC');
+        $this->setTimezone('UTC');
 
         // SEt user to GMT+5.
         $USER->timezone = 5;
@@ -179,7 +179,10 @@ public function test_is_available() {
      * Tests the get_description and get_standalone_description functions.
      */
     public function test_get_description() {
-        global $SITE;
+        global $SITE, $CFG;
+
+        $this->resetAfterTest();
+        $this->setTimezone('UTC');
 
         $modinfo = get_fast_modinfo($SITE);
         $info = new \core_availability\mock_info();