From 3a2d031bb5f5b4d6e5df06f8ec82957a1bc81a72 Mon Sep 17 00:00:00 2001
From: Gregor Kleen <gregor.kleen@ifi.lmu.de>
Date: Wed, 21 Jul 2021 14:46:54 +0200
Subject: [PATCH] fix(authorship-statements): resolve exam-part to exam
 properly

---
 src/Handler/Utils/AuthorshipStatement.hs | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/Handler/Utils/AuthorshipStatement.hs b/src/Handler/Utils/AuthorshipStatement.hs
index 7fa8d6d86..9822ef739 100644
--- a/src/Handler/Utils/AuthorshipStatement.hs
+++ b/src/Handler/Utils/AuthorshipStatement.hs
@@ -75,10 +75,12 @@ getSheetAuthorshipStatement (Entity _ Sheet{..}) = withCompatibleBackend @SqlBac
     E.where_ $ course E.^. CourseId E.==. E.val sheetCourse
     return school
 
-  let examId = sheetAuthorshipStatementExam
-           <|> sheetType ^? _examPart . re _SqlKey
-           <|> sheetRequireExamRegistration
-  exam <- lift $ traverse getJust examId
+  let examId = fmap Right sheetAuthorshipStatementExam
+           <|> fmap Left (sheetType ^? _examPart . re _SqlKey)
+           <|> fmap Right sheetRequireExamRegistration
+  exam <- lift . for examId $ \case
+    Right e -> getJust e
+    Left epId -> getJust epId >>= getJust . examPartExam
 
   let
     examAuthorshipStatement' = exam >>= examAuthorshipStatement