From 740e84573aaef4e3d087baaf6774f6f3734aa604 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Sun, 7 Jun 2026 20:58:17 +0000
Subject: [PATCH] fix: harden error handling and prevent uncaught async
 rejections

- Add null guards to showError/showSuccess so tests and pre-DOM calls
  don't throw when message elements are absent
- Return early from onload when Supabase is not configured so
  loadPlayers/loadMatches are never called with empty credentials
- Surface ELO revert failures to the user via showError instead of
  silently logging them
- Wrap window.recordMatch/recordDoublesMatch/addPlayer with .catch so
  unhandled promise rejections from HTML onclick attributes are shown

https://claude.ai/code/session_01TgxiTLy7fCh5xZPJT8eTVt
---
 app.js    | 8 +++++---
 src/ui.js | 2 ++
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/app.js b/app.js
index 1cfc8ca..54b9f86 100644
--- a/app.js
+++ b/app.js
@@ -65,9 +65,9 @@ window.clearTeams = clearSelections;
 
 window.filterPlayers = filterPlayerList;
 
-window.recordMatch        = recordMatch;
-window.recordDoublesMatch = recordDoublesMatch;
-window.addPlayer          = addPlayer;
+window.recordMatch        = () => recordMatch().catch(err => showError(err.message));
+window.recordDoublesMatch = () => recordDoublesMatch().catch(err => showError(err.message));
+window.addPlayer          = () => addPlayer().catch(err => showError(err.message));
 
 // ================= INITIALISIERUNG =================
 
@@ -81,6 +81,7 @@ window.onload = async function() {
 
     if (!_cfg.SUPABASE_URL || !_cfg.SUPABASE_ANON_KEY) {
         showError('Supabase nicht konfiguriert. Bitte config.js anlegen (siehe config.example.js).');
+        return;
     }
 
     await loadPlayers();
@@ -325,6 +326,7 @@ async function saveMatch(match, playerEntries) {
             await Promise.all(playerEntries.map(({ id }) => updatePlayer(id, state.players[id])));
         } catch (revertErr) {
             console.error('ELO-Revert fehlgeschlagen:', revertErr);
+            showError('ELO-Synchronisation fehlgeschlagen. Bitte Seite neu laden.');
         }
         showError('Fehler beim Speichern. Match wurde nicht übertragen.');
     } finally {
diff --git a/src/ui.js b/src/ui.js
index d79e9b1..e9d7ff1 100644
--- a/src/ui.js
+++ b/src/ui.js
@@ -16,6 +16,7 @@ export function getAvatarEmoji(playerId) {
 
 export function showError(message) {
     const el = document.getElementById('errorMessage');
+    if (!el) { console.error(message); return; }
     el.textContent = message;
     el.style.display = 'block';
     setTimeout(() => { el.style.display = 'none'; }, 5000);
@@ -23,6 +24,7 @@ export function showError(message) {
 
 export function showSuccess(message) {
     const el = document.getElementById('successMessage');
+    if (!el) { console.log(message); return; }
     el.textContent = message;
     el.style.display = 'block';
     setTimeout(() => { el.style.display = 'none'; }, 5000);