From ca0260cdf205111ec27dc260a5b742adf0ac832e Mon Sep 17 00:00:00 2001
From: Joseph Lee <joseph.lee22590@gmail.com>
Date: Sat, 23 Jan 2021 09:22:03 -0800
Subject: [PATCH] Cart explorer: initialize cart timestamps as an empty list
 instead of None.

Rather than using None to initialize cart edit timestamp, initialize it as an empty list. Also, when closing Studio app module, reset edit timestamps as an empty list.
This will be backported to LTS20.
---
 addon/appModules/splstudio/__init__.py | 4 ++--
 addon/appModules/splstudio/splmisc.py  | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/addon/appModules/splstudio/__init__.py b/addon/appModules/splstudio/__init__.py
index 40ef45b97..d5d325da4 100644
--- a/addon/appModules/splstudio/__init__.py
+++ b/addon/appModules/splstudio/__init__.py
@@ -1194,7 +1194,7 @@ def terminate(self):
 		self.carts.clear()
 		self._cachedStatusObjs.clear()
 		# Don't forget to reset timestamps for cart files.
-		splmisc._cartEditTimestamps = None
+		splmisc._cartEditTimestamps = []
 		# Just to make sure:
 		if splbase._SPLWin:
 			splbase._SPLWin = None
@@ -1609,7 +1609,7 @@ def script_toggleCartExplorer(self, gesture):
 			self.cartExplorer = False
 			self.cartsBuilder(build=False)
 			self.carts.clear()
-			splmisc._cartEditTimestamps = None
+			splmisc._cartEditTimestamps = []
 			# Translators: Presented when cart explorer is off.
 			ui.message(_("Exiting cart explorer"))
 
diff --git a/addon/appModules/splstudio/splmisc.py b/addon/appModules/splstudio/splmisc.py
index b98405a92..6bcd314a0 100755
--- a/addon/appModules/splstudio/splmisc.py
+++ b/addon/appModules/splstudio/splmisc.py
@@ -306,7 +306,7 @@ def _populateCarts(carts, cartlst, modifier, standardEdition=False, refresh=Fals
 
 
 # Cart file timestamps.
-_cartEditTimestamps = None
+_cartEditTimestamps = []
 
 
 # Initialize Cart Explorer i.e. fetch carts.