From e73a16e7b45e19a55ec3017b099080cb0ae94fa2 Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Fri, 2 Jun 2017 11:13:03 +0200
Subject: [PATCH] when drawing constraint icon handle the case when view
 provider of sketch is not in sync with geometry

---
 src/Mod/Sketcher/Gui/ViewProviderSketch.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp b/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp
index 0261f93984..9d1a1a8af3 100644
--- a/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp
+++ b/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp
@@ -2796,6 +2796,12 @@ void ViewProviderSketch::drawConstraintIcons()
             break;
         }
 
+        // Double-check that we can safely access the Inventor nodes
+        if (constrId >= edit->constrGroup->getNumChildren()) {
+            Base::Console().Warning("Can't update constraint icons because view is not in sync with sketch\n");
+            break;
+        }
+
         // Find the Constraint Icon SoImage Node
         SoSeparator *sep = static_cast<SoSeparator *>(edit->constrGroup->getChild(constrId));