From c683d3d83414ce0f352dbb421a027615366c71e1 Mon Sep 17 00:00:00 2001
From: David Rose <david@ddrose.com>
Date: Sat, 31 May 2003 00:16:34 +0000
Subject: [PATCH] collision handler pointer may have already been removed

---
 panda/src/collide/collisionTraverser.cxx | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/panda/src/collide/collisionTraverser.cxx b/panda/src/collide/collisionTraverser.cxx
index 229f1a5767..535bb23df1 100644
--- a/panda/src/collide/collisionTraverser.cxx
+++ b/panda/src/collide/collisionTraverser.cxx
@@ -142,11 +142,14 @@ remove_collider(CollisionNode *node) {
 
   // Update the set of handlers.
   Handlers::iterator hi = _handlers.find(handler);
-  nassertr(hi != _handlers.end(), false);
-  (*hi).second--;
-  nassertr((*hi).second >= 0, false);
-  if ((*hi).second == 0) {
-    _handlers.erase(hi);
+  // It's possible that the handler doesn't exist in the list (it may
+  // have removed itself if it detected some internal error).
+  if (hi != _handlers.end()) {
+    (*hi).second--;
+    nassertr((*hi).second >= 0, false);
+    if ((*hi).second == 0) {
+      _handlers.erase(hi);
+    }
   }
 
   _colliders.erase(ci);