From 47e0505b7382b0fd52988af24815c694ca7b4e7f Mon Sep 17 00:00:00 2001
From: Nils <>
Date: Sat, 13 Feb 2021 20:16:26 +0100
Subject: [PATCH] update template

---
 template/engine/sequencer.py | 13 ++++++++++++-
 template/qtgui/mainwindow.py |  1 +
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/template/engine/sequencer.py b/template/engine/sequencer.py
index 2541da2..a68af4f 100644
--- a/template/engine/sequencer.py
+++ b/template/engine/sequencer.py
@@ -61,6 +61,7 @@ class Score(Data):
         self.tracks = [] #see docstring
         self.tempoMap = TempoMap(parentData = self)
         self._template_processAfterInit()
+        self._tracksFailedLookup = []
 
     def _template_processAfterInit(self): #needs a different name because there is an inherited class with the same method.
         """Call this after either init or instanceFromSerializedData"""
@@ -119,11 +120,21 @@ class Score(Data):
         except Exception as e: #No Jack Meta Data or Error with ports.
             logger.error(e)
 
+
     def trackById(self, trackId:int):
+        """Returns a track or None, if not found"""
         for track in self.tracks:
             if trackId == id(track):
                 return track
-        raise ValueError(f"Track {trackId} not found. Current Tracks: {[id(tr) for tr in self.tracks]}")
+        else:
+            #Previously this crashed with a ValueError. However, after a rare bug that a gui widget focussed out because a track was deleted and then tried to send its value to the engine we realize that this lookup can gracefully return None.
+            #Nothing will break: Functions that are not aware yet, that None is an option will crash when they try to access None as a track object. For this case we present the following logger error:
+            if not trackId in self._tracksFailedLookup:
+                logger.error(f"Track {trackId} not found. Current Tracks: {[id(tr) for tr in self.tracks]}")
+                self._tracksFailedLookup.append(trackId) #prevent multiple error messages for the same track in a row.
+                return None
+                #raise ValueError(f"Track {trackId} not found. Current Tracks: {[id(tr) for tr in self.tracks]}")
+
 
 
     #Save / Load / Export
diff --git a/template/qtgui/mainwindow.py b/template/qtgui/mainwindow.py
index 9c4149c..4e9ee7a 100644
--- a/template/qtgui/mainwindow.py
+++ b/template/qtgui/mainwindow.py
@@ -57,6 +57,7 @@ api.session.eventLoop = EventLoop()
 
 #Setup the translator before classes are set up. Otherwise we can't use non-template translation.
 #to test use LANGUAGE=de_DE.UTF-8   . not LANG=
+#Language variants like de_AT.UTF-8 will be detected automatically and will result in Qt language detection as "German"
 language = QtCore.QLocale().languageToString(QtCore.QLocale().language())
 logger.info("{}: Language set to {}".format(METADATA["name"], language))
 if language in METADATA["supportedLanguages"]: