prevent php8 warnings, fixes #2402

Closes #2402

Merge request studip/studip!1595

app/views/my_courses/groups.php

-<form method="post" action="<?= $controller->url_for('my_courses/store_groups/'.$studygroups) ?>" class="default">
+<form method="post" action="<?= $controller->link_for('my_courses/store_groups/'.$studygroups) ?>" class="default">
     <?= CSRFProtection::tokenTag() ?>
 
-    <input type="hidden" name="cid" value="<?= $cid ?>">
+    <input type="hidden" name="cid" value="<?= htmlReady($cid) ?>">
     <table class="default collapsable">
         <caption><?= _('Gruppenzuordnung') ?></caption>
         <colgroup>
@@ -17,7 +17,7 @@
             </tr>
         </thead>
         <? foreach ($groups as $group_id => $group_members): ?>
-            <tbody class="<?= $current_semester != $semesters[$group_id]['semester_id'] ? 'collapsed' : ''?>">
+            <tbody <? if (isset($semesters[$group_id]['semester_id']) && $current_semester != $semesters[$group_id]['semester_id']) echo 'class="collapsed"'; ?>>
             <? if ($group_field !== 'not_grouped'): ?>
 
                 <tr class="table_header header-row">

app/views/questionnaire/question_types/vote/vote_evaluation.php

@@ -21,6 +21,14 @@ if ($numTaskAnswers > 0) {
             }
         } else {
             if (isset($answer['answerdata']['answers'])) {
+                if (!isset($results[(int) $answer['answerdata']['answers']])) {
+                    $results[(int) $answer['answerdata']['answers']] = 0;
+                }
+                $results[(int) $answer['answerdata']['answers']]++;
+
+                if (!isset($results_users[(int) $answer['answerdata']['answers']])) {
+                    $results_users[(int) $answer['answerdata']['answers']] = [];
+                }
                 $results[(int) $answer['answerdata']['answers']]++;
                 $results_users[(int) $answer['answerdata']['answers']][] = $answer['user_id'];
             }
@@ -76,7 +84,7 @@ rsort($ordered_results);
         <? $countAnswers = $vote->questionnaire->countAnswers() ?>
         <? foreach ($options as $key => $answer) : ?>
         <tr>
-            <? $percentage = $countAnswers ? round((int) $results[$key] / $countAnswers * 100) : 0 ?>
+            <? $percentage = ($countAnswers && isset($results[$key])) ? round((int) $results[$key] / $countAnswers * 100) : 0 ?>
 
             <td style="text-align: right; background-size: <?= $percentage ?>% 100%; background-position: right center; background-image: url('<?= Assets::image_path("vote_lightgrey.png") ?>'); background-repeat: no-repeat;" width="50%">
                 <strong><?= formatReady($answer) ?></strong>

templates/shared/pagechooser.php

@@ -22,7 +22,7 @@
     aria-labelledby="pagination-label-<?= $random_id ?>">
 <? if ($cur_page > 1): ?>
     <li class="prev">
-        <a class="pagination--link" href="<?= URLHelper::getLink(sprintf($pagelink, $cur_page - 1), $pageparams) ?>" rel="prev" <?= $dialog ?: ''?>>
+        <a class="pagination--link" href="<?= URLHelper::getLink(sprintf($pagelink, $cur_page - 1), $pageparams) ?>" rel="prev" <?= $dialog ?? '' ?>>
             <span class="audible"><?= _('Eine Seite') ?></span>
             <?= _('zurück') ?>
         </a>