Resolve "PHP8 Warning bei Export von Ablaufplan"

Closes #4399

Merge request studip/studip!3213

app/views/course/dates/export.php

@@ -19,18 +19,21 @@
         <?
         $all_semester = Semester::findAllVisible(false);
 
+        $grenze = 0;
         foreach ($dates as $date) :
             if ( ($grenze == 0) || ($grenze < $date['start']) ) {
                 foreach ($all_semester as $zwsem) {
-                    if ( ($zwsem['beginn'] < $date['start']) && ($zwsem['ende'] > $date['start']) ) {
-                        $grenze = $zwsem['ende'];
-                        ?>
-                        <tr>
-                            <td colspan="5">
-                                <h3><?= htmlReady($zwsem['name']) ?></h3>
-                            </td>
-                        </tr>
-                    <?
+                    if (!empty($zwsem['beginn'])) {
+                        if ( ($zwsem['beginn'] < $date['start']) && ($zwsem['ende'] > $date['start']) ) {
+                            $grenze = $zwsem['ende'];
+                            ?>
+                            <tr>
+                                <td colspan="5">
+                                    <h3><?= htmlReady($zwsem['name']) ?></h3>
+                                </td>
+                            </tr>
+                        <?
+                        }
                     }
                 }
             }

lib/raumzeit/Issue.php

@@ -62,10 +62,10 @@ class Issue {
     function __construct($data = []) {
         global $user;
 
-        if ($data['issue_id']) {
+        if (!empty($data['issue_id'])) {
             $this->issue_id = $data['issue_id'];
             $this->restore();
-        } else if ($data['seminar_id']) {
+        } else if (!empty($data['seminar_id'])) {
             $this->issue_id = md5(uniqid('Issue'));
             $this->seminar_id = $data['seminar_id'];
             $this->mkdate = time();
@@ -190,7 +190,7 @@ class Issue {
         $this->mkdate = $data['mkdate'];
         $this->chdate = $data['chdate'];
         $this->priority = $data['priority'];
-        $this->file = ($data['range_id'] == '') ? FALSE : TRUE;
+        $this->file = !empty($data['range_id']);
         if ($this->file) {
             $this->folder_id = $data['folder_id'];
         }