From 344058baba2294784050adb91e0ca75cba8102bf Mon Sep 17 00:00:00 2001
From: James Turner <james@flightgear.org>
Date: Tue, 23 Mar 2021 17:07:59 +0000
Subject: [PATCH] Avoid crash when early-exiting.

This is a work-around, but suitable for back-porting to 2020.3

Sentry-Id: FLIGHTGEAR-37D
---
 src/Model/modelmgr.cxx | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/Model/modelmgr.cxx b/src/Model/modelmgr.cxx
index 142ff6a7b..3235f6190 100644
--- a/src/Model/modelmgr.cxx
+++ b/src/Model/modelmgr.cxx
@@ -208,7 +208,12 @@ FGModelMgr::bind ()
 void
 FGModelMgr::unbind ()
 {
-    _models->removeChangeListener(_listener.get());
+    // work-around for FLIGHTGEAR-37D : crash when quitting during
+    // early startup
+    if (!_listener) {
+        _models->removeChangeListener(_listener.get());
+    }
+
     _listener.reset();
     _models.clear();
 }