From 99d4cb7ad5ac36a5bebd4f34220fe8b7bf87354b Mon Sep 17 00:00:00 2001
From: MetalStormGhost <89945461+MetalStormGhost@users.noreply.github.com>
Date: Thu, 27 Jan 2022 10:43:31 +0200
Subject: [PATCH] Tolerate empty TGOs in max_threat_range.

cherry-pick from 3231d00
---
 game/theater/theatergroundobject.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/game/theater/theatergroundobject.py b/game/theater/theatergroundobject.py
index 51c5bc50..8771fb2a 100644
--- a/game/theater/theatergroundobject.py
+++ b/game/theater/theatergroundobject.py
@@ -176,7 +176,9 @@ class TheaterGroundObject(MissionTarget, Generic[GroupT]):
         return self._max_range_of_type(group, "detection_range")
 
     def max_threat_range(self) -> Distance:
-        return max(self.threat_range(g) for g in self.groups)
+        return (
+            max(self.threat_range(g) for g in self.groups) if self.groups else meters(0)
+        )
 
     def threat_range(self, group: GroupT, radar_only: bool = False) -> Distance:
         return self._max_range_of_type(group, "threat_range")