prevent php8-warnings, closes #1770

Closes #1770

Merge request studip/studip!1148

12 files changed, 91 insertions, 81 deletions

diff --git a/lib/admissionrules/conditionaladmission/ConditionalAdmission.class.php b/lib/admissionrules/conditionaladmission/ConditionalAdmission.class.php
index 900ee5b..63275f0 100644
--- a/lib/admissionrules/conditionaladmission/ConditionalAdmission.class.php
+++ b/lib/admissionrules/conditionaladmission/ConditionalAdmission.class.php
@@ -55,14 +55,14 @@ class ConditionalAdmission extends AdmissionRule
     /**
      * Standard constructor.
      *
-     * @param  String ruleId If this rule has been saved previously, it
+     * @param  String $ruleId If this rule has been saved previously, it
      *      will be loaded from database.
-     * @return AdmissionRule the current object (this).
+     * @return ConditionalAdmission the current object (this).
      */
     public function __construct($ruleId='', $courseSetId = '')
     {
         parent::__construct($ruleId, $courseSetId);
-        $this->default_message = _("Sie erfüllen nicht die Bedingung: %s");
+        $this->default_message = _('Sie erfüllen nicht die Bedingung: %s');
         if ($ruleId) {
             $this->load();
         } else {
@@ -74,9 +74,9 @@ class ConditionalAdmission extends AdmissionRule
     /**
      * Adds a new UserFilter to this rule.
      *
-     * @param  UserFilter condition
-     * @param  String group
-     * @param  Int quota
+     * @param  UserFilter $condition
+     * @param  String $group
+     * @param  Int $quota
      * @return ConditionalAdmission
      */
     public function addCondition($condition, $group = '', $quota = 0)
@@ -282,7 +282,7 @@ class ConditionalAdmission extends AdmissionRule
     /**
      * Removes the condition with the given ID from the rule.
      *
-     * @param  String conditionId
+     * @param  String $conditionId
      * @return ConditionalAdmission
      */
     public function removeCondition($conditionId)
@@ -336,8 +336,6 @@ class ConditionalAdmission extends AdmissionRule
                     }
                 }
             }
-        } else {
-            $failed = [];
         }
         return $failed;
     }
@@ -360,7 +358,7 @@ class ConditionalAdmission extends AdmissionRule
         $this->quota = [];
         foreach ($data['conditions'] as $ser_con) {
             $condition = ObjectBuilder::build($ser_con, 'UserFilter');
-            $this->addCondition($condition, $data['conditiongroup_'.$condition->getId()], $data['quota_'.$data['conditiongroup_'.$condition->getId()]]);
+            $this->addCondition($condition, $data['conditiongroup_'.$condition->getId()], $data['quota_'.$data['conditiongroup_'.$condition->getId()]] ?? 0);
         }
         foreach ($this->getConditiongroups() as $conditiongroup_id => $conditions) {
             if (mb_strlen($conditiongroup_id) < 32) {
@@ -483,7 +481,7 @@ class ConditionalAdmission extends AdmissionRule
      * Validates if the given request data is sufficient to configure this rule
      * (e.g. if required values are present).
      *
-     * @param  Array Request data
+     * @param  Array $data Request data
      * @return Array Error messages.
      */
     public function validate($data)
@@ -505,12 +503,12 @@ class ConditionalAdmission extends AdmissionRule
             } else {
                 $ungrouped++;
             }
-            $quota[$data['conditiongroup_' . $condition->getId()]] = $data['quota_' . $data['conditiongroup_' . $condition->getId()]];
+            $quota[$data['conditiongroup_' . $condition->getId()]] = $data['quota_' . $data['conditiongroup_' . $condition->getId()]] ?? 0;
             if (!$quota[$data['conditiongroup_' . $condition->getId()]]) {
                 $no_quota++;
             }
         }
-        foreach ($quota as $id => $part) {
+        foreach ($quota as $part) {
             $quota_total += $part;
         }
         if ($grouped && $ungrouped) {
@@ -562,6 +560,4 @@ class ConditionalAdmission extends AdmissionRule
         parent::setSiblings($siblings);
         $this->conditiongroups_allowed = null;
     }
-
-} /* end of class ConditionalAdmission */
-
+}
diff --git a/lib/admissionrules/coursememberadmission/CourseMemberAdmission.class.php b/lib/admissionrules/coursememberadmission/CourseMemberAdmission.class.php
index 74892fd..dc13a62 100644
--- a/lib/admissionrules/coursememberadmission/CourseMemberAdmission.class.php
+++ b/lib/admissionrules/coursememberadmission/CourseMemberAdmission.class.php
@@ -32,7 +32,8 @@ class CourseMemberAdmission extends AdmissionRule
     /**
      * Standard constructor
      *
-     * @param  String ruleId
+     * @param  String $ruleId
+     * @param  String e
      */
     public function __construct($ruleId = '', $courseSetId = '')
     {
@@ -115,8 +116,8 @@ class CourseMemberAdmission extends AdmissionRule
     /**
      * Is admission allowed according to the defined time frame?
      *
-     * @param  String userId
-     * @param  String courseId
+     * @param  String $userId
+     * @param  String $courseId
      * @return Array
      */
     public function ruleApplies($userId, $courseId)
@@ -193,7 +194,7 @@ class CourseMemberAdmission extends AdmissionRule
      * Validates if the given request data is sufficient to configure this rule
      * (e.g. if required values are present).
      *
-     * @param  Array Request data
+     * @param  Array $data Request data
      * @return Array Error messages.
      */
     public function validate($data)
diff --git a/lib/admissionrules/participantrestrictedadmission/ParticipantRestrictedAdmission.class.php b/lib/admissionrules/participantrestrictedadmission/ParticipantRestrictedAdmission.class.php
index 1556db3..a64b88a 100644
--- a/lib/admissionrules/participantrestrictedadmission/ParticipantRestrictedAdmission.class.php
+++ b/lib/admissionrules/participantrestrictedadmission/ParticipantRestrictedAdmission.class.php
@@ -36,9 +36,10 @@ class ParticipantRestrictedAdmission extends AdmissionRule
     /**
      * Standard constructor
      *
-     * @param  String ruleId
+     * @param  String $ruleId
+     * @param  String $courseSetId
      */
-    public function __construct($ruleId='', $courseSetId = '')
+    public function __construct($ruleId = '', $courseSetId = '')
     {
         parent::__construct($ruleId, $courseSetId);
         $this->first_come_first_served_allowed = (bool)Config::get()->ENABLE_COURSESET_FCFS;
@@ -58,7 +59,8 @@ class ParticipantRestrictedAdmission extends AdmissionRule
     /**
      * Deletes the admission rule and all associated data.
      */
-    public function delete() {
+    public function delete()
+    {
         if ($this->prio_exists) {
             $set_id = DBManager::get()->fetchColumn("SELECT set_id FROM courseset_rule WHERE rule_id = ? LIMIT 1", [$this->id]);
             //Delete priorities
@@ -75,7 +77,8 @@ class ParticipantRestrictedAdmission extends AdmissionRule
      * Gets some text that describes what this AdmissionRule (or respective
      * subclass) does.
      */
-    public static function getDescription() {
+    public static function getDescription()
+    {
         return _("Anmelderegeln dieses Typs legen fest, ob die zugeordneten Veranstaltungen eine maximale Teilnehmendenanzahl haben. Die Platzverteilung erfolgt automatisiert.");
     }
 
@@ -92,7 +95,8 @@ class ParticipantRestrictedAdmission extends AdmissionRule
     /**
      * Return this rule's name.
      */
-    public static function getName() {
+    public static function getName()
+    {
         return _("Beschränkte Teilnehmendenanzahl");
     }
 
@@ -101,7 +105,8 @@ class ParticipantRestrictedAdmission extends AdmissionRule
      *
      * @return String
      */
-    public function getTemplate() {
+    public function getTemplate()
+    {
         $factory = new Flexi_TemplateFactory(dirname(__FILE__).'/templates/');
         // Open specific template for this rule and insert base template.
         $tpl = $factory->open('configure');
@@ -112,7 +117,8 @@ class ParticipantRestrictedAdmission extends AdmissionRule
     /**
      * Helper function for loading rule definition from database.
      */
-    public function load() {
+    public function load()
+    {
         // Load data.
         $stmt = DBManager::get()->prepare("SELECT *
             FROM `participantrestrictedadmissions` WHERE `rule_id`=? LIMIT 1");
@@ -134,19 +140,20 @@ class ParticipantRestrictedAdmission extends AdmissionRule
      * @param Array $data
      * @return AdmissionRule This object.
      */
-    public function setAllData($data) {
+    public function setAllData($data)
+    {
         parent::setAllData($data);
-        if ($data['distributiondate']) {
+        if (!empty($data['distributiondate'])) {
             if (!$data['distributiontime']) {
                 $data['distributiontime'] = '23:59';
             }
             $ddate = strtotime($data['distributiondate'] . ' ' . $data['distributiontime']);
             $this->setDistributionTime($ddate);
         }
-        if ($data['enable_FCFS']) {
+        if (!empty($data['enable_FCFS'])) {
             $this->setDistributionTime(0);
         }
-        if ($data['startdate']) {
+        if (!empty($data['startdate'])) {
              $starttime = strtotime($data['startdate'] . ' ' . $data['starttime']);
              if ($starttime > time()) {
                  $this->minimum_timespan_to_distribution_time = $this->minimum_timespan_to_distribution_time + (($starttime - time()) / 60);
@@ -159,8 +166,8 @@ class ParticipantRestrictedAdmission extends AdmissionRule
     /**
      * Sets a new timestamp for seat distribution algorithm execution.
      *
-     * @param  int newDistributionTime
-     * @return TimedAdmission
+     * @param  int $newDistributionTime
+     * @return ParticipantRestrictedAdmission
      */
     public function setDistributionTime($newDistributionTime)
     {
@@ -172,7 +179,8 @@ class ParticipantRestrictedAdmission extends AdmissionRule
     /**
      * Store rule definition to database.
      */
-    public function store() {
+    public function store()
+    {
         // Store data.
         $stmt = DBManager::get()->prepare("INSERT INTO `participantrestrictedadmissions`
             (`rule_id`, `message`, `distribution_time`,
@@ -201,7 +209,7 @@ class ParticipantRestrictedAdmission extends AdmissionRule
      * Validates if the given request data is sufficient to configure this rule
      * (e.g. if required values are present).
      *
-     * @param  Array Request data
+     * @param  Array $data Request data
      * @return Array Error messages.
      */
     public function validate($data)
@@ -211,15 +219,12 @@ class ParticipantRestrictedAdmission extends AdmissionRule
             $data['distributiontime'] = '23:59';
         }
         $ddate = strtotime($data['distributiondate'] . ' ' . $data['distributiontime']);
-        if (!$data['enable_FCFS'] && (!$data['distributiondate'] || $ddate < (time() + $this->minimum_timespan_to_distribution_time*60))) {
+        if (empty($data['enable_FCFS']) && (empty($data['distributiondate']) || $ddate < (time() + $this->minimum_timespan_to_distribution_time * 60))) {
             $errors[] = sprintf(_('Bitte geben Sie für die Platzverteilung ein Datum an, das weiter in der Zukunft liegt. Das frühestmögliche Datum ist %s.'), strftime('%x %R', time() + $this->minimum_timespan_to_distribution_time*60));
         }
-        if ($data['enable_FCFS'] && $data['distributiondate']) {
+        if (!empty($data['enable_FCFS']) && $data['distributiondate']) {
             $errors[] = _('Sie können kein Datum für die automatische Platzverteilung einstellen und gleichzeitig die automatische Platzverteilung ausschalten.');
         }
         return $errors;
     }
-
 }
-
-?>
diff --git a/lib/classes/RangeTreeObject.class.php b/lib/classes/RangeTreeObject.class.php
index c4c5320..579db43 100644
--- a/lib/classes/RangeTreeObject.class.php
+++ b/lib/classes/RangeTreeObject.class.php
@@ -95,7 +95,7 @@ class RangeTreeObject {
     function __construct($item_id) {
         $this->tree = TreeAbstract::GetInstance("StudipRangeTree", false);
         $this->tree_item_id = $item_id;
-        $this->item_data = $this->tree->tree_data[$item_id];
+        $this->item_data = $this->tree->tree_data[$item_id] ?? null;
     }
 
     /**
diff --git a/lib/classes/Request.class.php b/lib/classes/Request.class.php
index 22cf29d..3402972 100644
--- a/lib/classes/Request.class.php
+++ b/lib/classes/Request.class.php
@@ -778,7 +778,7 @@ class Request implements ArrayAccess, IteratorAggregate
     {
         try {
             $request = self::getInstance();
-            return ObjectBuilder::buildMany($request[$param] ?: null, $expected_class);
+            return ObjectBuilder::buildMany($request[$param] ?? null, $expected_class);
         } catch (Exception $e) {
             if ($allow_null) {
                 return [];
diff --git a/lib/classes/StudipSemSearchHelper.class.php b/lib/classes/StudipSemSearchHelper.class.php
index ea7aa9c..bb45d24 100644
--- a/lib/classes/StudipSemSearchHelper.class.php
+++ b/lib/classes/StudipSemSearchHelper.class.php
@@ -52,7 +52,8 @@ class StudipSemSearchHelper {
         $this->setParams($params, $visible_only);
     }
 
-    public function setParams($params, $visible_only = null){
+    public function setParams($params, $visible_only = null)
+    {
         if(isset($params['quick_search']) && isset($params['qs_choose'])){
             if($params['qs_choose'] == 'all'){
                 foreach (self::GetQuickSearchFields() as $key => $value){
@@ -181,11 +182,11 @@ class StudipSemSearchHelper {
                 $view->params[0] = '';
             }
             $view->params[0] .= ($this->params['title']) ? $search_for . " " : " ";
-            $view->params[0] .= ($this->params['title'] && $this->params['sub_title']) ? $combination : " ";
-            $view->params[0] .= ($this->params['sub_title']) ? " Untertitel LIKE '%" . $this->trim($this->params['sub_title']) . "%' " : " ";
-            $view->params[0] .= (($this->params['title'] || $this->params['sub_title']) && $this->params['comment']) ? $combination : " ";
-            $view->params[0] .= ($this->params['comment']) ? " Beschreibung LIKE '%" . $this->trim($this->params['comment']) . "%' " : " ";
-            $view->params[0] .= (($this->params['title'] || $this->params['sub_title'] || $this->params['comment']) && $this->params['number']) ? $combination : " ";
+            $view->params[0] .= ($this->params['title'] && !empty($this->params['sub_title'])) ? $combination : " ";
+            $view->params[0] .= (!empty($this->params['sub_title'])) ? " Untertitel LIKE '%" . $this->trim($this->params['sub_title']) . "%' " : " ";
+            $view->params[0] .= (($this->params['title'] || !empty($this->params['sub_title'])) && !empty($this->params['comment'])) ? $combination : " ";
+            $view->params[0] .= (!empty($this->params['comment'])) ? " Beschreibung LIKE '%" . $this->trim($this->params['comment']) . "%' " : " ";
+            $view->params[0] .= (($this->params['title'] || !empty($this->params['sub_title']) || empty($this->params['comment'])) && $this->params['number']) ? $combination : " ";
             $view->params[0] .= ($this->params['number']) ? " VeranstaltungsNummer LIKE '%" . $this->trim($this->params['number']) . "%' " : " ";
             $view->params[0] = ($this->visible_only ? " c.visible=1 AND " : "") . "(" . $view->params[0] .")";
             $view->params[1] =  $and_clause . $clause;
diff --git a/lib/classes/TreeAbstract.class.php b/lib/classes/TreeAbstract.class.php
index 7cdb940..9f54654 100644
--- a/lib/classes/TreeAbstract.class.php
+++ b/lib/classes/TreeAbstract.class.php
@@ -95,7 +95,7 @@ class TreeAbstract {
     public static function GetInstance($class_name, $args = null, $invalidate_cache = false)
     {
         static $tree_instance;
-
+        $class_hash = '';
         if ($args){
             $class_hash = $class_name . "_" . md5(serialize($args));
         } elseif ($args === false && is_array($tree_instance)){
diff --git a/lib/classes/admission/AdmissionRule.class.php b/lib/classes/admission/AdmissionRule.class.php
index a174157..fe5e5bb 100644
--- a/lib/classes/admission/AdmissionRule.class.php
+++ b/lib/classes/admission/AdmissionRule.class.php
@@ -84,7 +84,7 @@ abstract class AdmissionRule
     /**
      * Checks if we are in the rule validity time frame.
      *
-     * @return True if the rule is valid because the time frame applies,
+     * @return bool True if the rule is valid because the time frame applies,
      *         otherwise false.
      */
     public function checkTimeFrame()
@@ -115,7 +115,7 @@ abstract class AdmissionRule
     /**
      * Generate a new unique ID.
      *
-     * @param  String tableName
+     * @param  String $tableName
      */
     public function generateId($tableName)
     {
@@ -273,7 +273,7 @@ abstract class AdmissionRule
      * Hook that can be called when the seat distribution on the courseset
      * starts.
      *
-     * @param CourseSet The courseset this rule belongs to.
+     * @param CourseSet $courseset The courseset this rule belongs to.
      */
     public function beforeSeatDistribution($courseset)
     {
@@ -284,8 +284,8 @@ abstract class AdmissionRule
      * Does the current rule allow the given user to register as participant
      * in the given course?
      *
-     * @param  String userId
-     * @param  String courseId
+     * @param  String $userId
+     * @param  String $courseId
      * @return Array
      */
     public function ruleApplies($userId, $courseId)
@@ -303,23 +303,23 @@ abstract class AdmissionRule
      */
     public function setAllData($data)
     {
-        if ($data['start_date'] && !$data['start_time']) {
+        if (!empty($data['start_date']) && empty($data['start_time'])) {
             $data['start_time'] = strtotime($data['start_date']);
         }
-        if ($data['end_date'] && !$data['end_time']) {
+        if (!empty($data['end_date']) && empty($data['end_time'])) {
             $data['end_time'] = strtotime($data['end_date'] . ' 23:59:59');
         }
-        $this->message = $data['message'];
-        $this->startTime = $data['start_time'];
-        $this->endTime = $data['end_time'];
+        $this->message = $data['message'] ?? '';
+        $this->startTime = $data['start_time'] ?? null;
+        $this->endTime = $data['end_time'] ?? null;
         return $this;
     }
 
     /**
      * Sets a new end time for condition validity.
      *
-     * @param  Integer newEndTime
-     * @return UserFilter
+     * @param  Integer $newEndTime
+     * @return AdmissionRule
      */
     public function setEndTime($newEndTime)
     {
@@ -330,7 +330,7 @@ abstract class AdmissionRule
     /**
      * Sets a new message to show to users.
      *
-     * @param  String newMessage A new message text.
+     * @param  String $newMessage A new message text.
      * @return AdmissionRule This object
      */
     public function setMessage($newMessage)
@@ -342,8 +342,8 @@ abstract class AdmissionRule
     /**
      * Sets a new start time for condition validity.
      *
-     * @param  Integer newStartTime
-     * @return UserFilter
+     * @param  Integer $newStartTime
+     * @return AdmissionRule
      */
     public function setStartTime($newStartTime)
     {
@@ -372,13 +372,13 @@ abstract class AdmissionRule
      * Validates if the given request data is sufficient to configure this rule
      * (e.g. if required values are present).
      *
-     * @param  Array Request data
+     * @param  Array $data Request data
      * @return Array Error messages.
      */
     public function validate($data)
     {
         $errors = [];
-        if ($data['start_date'] && $data['end_date'] && strtotime($data['end_date']) < strtotime($data['start_date'])) {
+        if (!empty($data['start_date']) && !empty($data['end_date']) && strtotime($data['end_date']) < strtotime($data['start_date'])) {
             $errors[] = _('Das Enddatum darf nicht vor dem Startdatum liegen.');
         }
         return $errors;
@@ -389,7 +389,8 @@ abstract class AdmissionRule
      *
      * @return String
      */
-    public function __toString() {
+    public function __toString()
+    {
         return $this->toString();
     }
 
@@ -452,4 +453,4 @@ abstract class AdmissionRule
         $this->id = md5(uniqid(get_class($this)));
         $this->courseSetId = null;
     }
-} /* end of abstract class AdmissionRule */
+}
diff --git a/lib/classes/sidebar/SearchWidget.php b/lib/classes/sidebar/SearchWidget.php
index 40a2eb9..82aa26b 100644
--- a/lib/classes/sidebar/SearchWidget.php
+++ b/lib/classes/sidebar/SearchWidget.php
@@ -147,11 +147,11 @@ class SearchWidget extends SidebarWidget
                 unset($reset_params[$needle['name']]);
 
                 // Search view in Wiki must be cleared.
-                if ($reset_params['view'] == 'search') {
+                if (isset($reset_params['view']) && $reset_params['view'] === 'search') {
                     $reset_params['view'] = 'show';
                 }
                 // Search view in Forum must be cleared.
-                if ($reset_params['backend'] == 'search') {
+                if (isset($reset_params['backend']) && $reset_params['backend'] === 'search') {
                     unset($reset_params['backend']);
                     $this->url = str_replace('index/search', 'index', $this->url);
                 }
diff --git a/lib/export/export_studipdata_func.inc.php b/lib/export/export_studipdata_func.inc.php
index 1139f21..bc2b990 100644
--- a/lib/export/export_studipdata_func.inc.php
+++ b/lib/export/export_studipdata_func.inc.php
@@ -300,10 +300,11 @@ function export_inst($inst_id, $ex_sem_id = "all")
  */
 function export_sem($inst_id, $ex_sem_id = 'all')
 {
-    global $range_id, $xml_file, $o_mode, $xml_names_lecture, $xml_groupnames_lecture, $object_counter, $SEM_TYPE, $SEM_CLASS, $filter, $ex_sem, $ex_sem_class, $ex_person_details, $persons;
+    global $o_mode, $xml_names_lecture, $xml_groupnames_lecture, $object_counter, $SEM_TYPE, $SEM_CLASS, $filter, $ex_sem, $ex_sem_class, $ex_person_details, $persons;
 
     $ex_only_homeinst = Request::int('ex_only_homeinst', 0);
-
+    $addquery = '';
+    $addjoin = '';
     // Prepare user count statement
     $query           = "SELECT COUNT(user_id)
               FROM seminar_user
@@ -320,7 +321,9 @@ function export_sem($inst_id, $ex_sem_id = 'all')
               WHERE seminar_user.status = 'dozent' AND seminar_user.Seminar_id = ?
               ORDER BY seminar_user.position";
     $inner_statement = DBManager::get()->prepare($query);
-
+    $do_group = false;
+    $group = null;
+    $group_tab_zelle = null;
     // Prepare (build) and execute outmost query
     switch ($filter) {
         case "seminar":
@@ -476,7 +479,7 @@ function export_sem($inst_id, $ex_sem_id = 'all')
                 }
                 $data_object .= xml_close_tag($xml_groupnames_lecture['childgroup3a']);
             } elseif ($key === 'admission_turnout') {
-                $data_object .= xml_open_tag($val, $row['admission_type'] ? _('max.') : _('erw.'));
+                $data_object .= xml_open_tag($val, !empty($row['admission_type']) ? _('max.') : _('erw.'));
                 $data_object .= $row[$key];
                 $data_object .= xml_close_tag($val);
             } elseif ($key === 'teilnehmer_anzahl_aktuell') {
@@ -488,7 +491,7 @@ function export_sem($inst_id, $ex_sem_id = 'all')
             } elseif ($key === 'metadata_dates') {
                 $data_object .= xml_open_tag($xml_groupnames_lecture['childgroup1']);
                 $vorb        = vorbesprechung($row['seminar_id'], 'export');
-                if ($vorb != false) {
+                if ($vorb) {
                     $data_object .= xml_tag($val[0], $vorb);
                 }
                 if (($first_date = SeminarDB::getFirstDate($row['seminar_id']))
@@ -500,7 +503,7 @@ function export_sem($inst_id, $ex_sem_id = 'all')
                 $data_object .= xml_close_tag($xml_groupnames_lecture["childgroup1"]);
             } elseif ($key === 'Institut_id') {
                 $data_object .= xml_tag($val, $row['heimateinrichtung'], ['key' => $row[$key]]);
-            } elseif ($row[$key] !== '')
+            } elseif (isset($row[$key]) && $row[$key] !== '')
                 $data_object .= xml_tag($val, $row[$key]);
         }
 
diff --git a/lib/models/resources/ResourceRequest.class.php b/lib/models/resources/ResourceRequest.class.php
index 8b68fd0..c487841 100644
--- a/lib/models/resources/ResourceRequest.class.php
+++ b/lib/models/resources/ResourceRequest.class.php
@@ -1175,8 +1175,8 @@ class ResourceRequest extends SimpleORMap implements PrivacyObject, Studip\Calen
             if ($with_range) {
                 $interval['range']       = 'CourseDate';
                 $interval['range_id']    = $this->termin_id;
-                $interval['booked_room'] = $this->date->room_booking->resource_id;
-                $interval['booking_id']  = $this->date->room_booking->id;
+                $interval['booked_room'] = $this->date->room_booking ? $this->date->room_booking->resource_id: null;
+                $interval['booking_id']  = $this->date->room_booking ? $this->date->room_booking->id : null;
             }
             return [$interval];
         } elseif ($this->metadate_id) {
@@ -1271,8 +1271,11 @@ class ResourceRequest extends SimpleORMap implements PrivacyObject, Studip\Calen
 
             if ($interval['range'] == 'CourseDate') {
                 $date = call_user_func([$interval['range'], 'find'], $interval['range_id']);
-                if ($room_obj = Room::find($date->room_booking->resource_id)) {
-                    $room = $room_obj->name;
+                if ($date->room_booking) {
+                    $room_obj = Room::find($date->room_booking->resource_id);
+                    if ($room_obj) {
+                        $room = $room_obj->name;
+                    }
                 }
             }
 
diff --git a/lib/plugins/engine/PluginManager.class.php b/lib/plugins/engine/PluginManager.class.php
index 7ced174..5873eb2 100644
--- a/lib/plugins/engine/PluginManager.class.php
+++ b/lib/plugins/engine/PluginManager.class.php
@@ -619,7 +619,7 @@ class PluginManager
      */
     public function getPlugins ($type, $context = null)
     {
-        $user = $GLOBALS['user']->id ?: 'nobody';
+        $user = $GLOBALS['user'] ? $GLOBALS['user']->id : 'nobody';
         $plugin_info = $this->getPluginInfos($type);
         $plugins = [];