Fix clarifications for unlinked problems

Closes: #3032

Author: vmcj

webapp/src/Controller/Jury/ClarificationController.php

@@ -200,7 +200,12 @@ public function viewAction(Request $request, int $id): Response
             $clarcontest = $contest->getShortname();
             $data['subjectlink'] = null;
             if ($clar->getProblem()) {
-                $concernssubject = $contest->getCid() . "-" . $clar->getProblem()->getProbid();
+                if ($clar->getContestProblem()) {
+                    $concernssubject = $contest->getCid() . "-" . $clar->getProblem()->getProbid();
+                } else {
+                    // Very special case, this problem is unlinked.
+                    $concernssubject = "";
+                }
                 $data['subjectlink'] = $this->generateUrl('jury_problem', ['probId' => $clar->getProblem()->getProbid()]);
             } elseif ($clar->getCategory()) {
                 $concernssubject = $contest->getCid() . "-" . $clar->getCategory();

webapp/src/Twig/TwigExtension.php

@@ -1229,9 +1229,9 @@ private function hexToForegroundAndBorder(string $rgb): array
         return [$foreground, $border];
     }
 
-    public function problemBadge(ContestProblem $problem, bool $grayedOut = false): string
+    public function problemBadge(?ContestProblem $problem, bool $grayedOut = false): string
     {
-        $rgb = Utils::convertToHex($problem->getColor() ?? '#ffffff');
+        $rgb = Utils::convertToHex($problem?->getColor() ?? '#ffffff');
         if ($grayedOut || empty($rgb)) {
             $rgb = Utils::convertToHex('whitesmoke');
         }
@@ -1247,7 +1247,7 @@ public function problemBadge(ContestProblem $problem, bool $grayedOut = false):
             $rgb,
             $border,
             $foreground,
-            $problem->getShortname()
+            $problem?->getShortname() ?? '?'
         );
     }