From b9e79be0a7944a94ee95250f6e06f5c751c9d052 Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Sun, 14 Jun 2020 16:23:16 +0200
Subject: [PATCH] Sketcher: [skip ci] add security checks before accessing
 pointer

---
 src/Mod/Sketcher/Gui/ViewProviderSketch.cpp | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp b/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp
index d2161d76cf..2f79dcd7a4 100644
--- a/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp
+++ b/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp
@@ -3069,8 +3069,8 @@ void ViewProviderSketch::drawConstraintIcons()
             {   // second icon is available only for colinear line segments
                 const Part::Geometry *geo1 = getSketchObject()->getGeometry((*it)->First);
                 const Part::Geometry *geo2 = getSketchObject()->getGeometry((*it)->Second);
-                if (geo1->getTypeId() == Part::GeomLineSegment::getClassTypeId() &&
-                    geo2->getTypeId() == Part::GeomLineSegment::getClassTypeId()) {
+                if (geo1 && geo1->getTypeId() == Part::GeomLineSegment::getClassTypeId() &&
+                    geo2 && geo2->getTypeId() == Part::GeomLineSegment::getClassTypeId()) {
                     multipleIcons = true;
                 }
             }
@@ -5453,15 +5453,18 @@ void ViewProviderSketch::rebuildConstraintsVisual(void)
                 if ((*it)->Type == Tangent) {
                     const Part::Geometry *geo1 = getSketchObject()->getGeometry((*it)->First);
                     const Part::Geometry *geo2 = getSketchObject()->getGeometry((*it)->Second);
-                    if (geo1->getTypeId() == Part::GeomLineSegment::getClassTypeId() &&
-                        geo2->getTypeId() == Part::GeomLineSegment::getClassTypeId()) {
+                    if (!geo1 || !geo2) {
+                        Base::Console().Warning("Tangent constraint references non-existing geometry\n");
+                    }
+                    else if (geo1->getTypeId() == Part::GeomLineSegment::getClassTypeId() &&
+                             geo2->getTypeId() == Part::GeomLineSegment::getClassTypeId()) {
                         // #define CONSTRAINT_SEPARATOR_INDEX_SECOND_TRANSLATION 4
                         sep->addChild(new SoZoomTranslation());
                         // #define CONSTRAINT_SEPARATOR_INDEX_SECOND_ICON 5
                         sep->addChild(new SoImage());
                         // #define CONSTRAINT_SEPARATOR_INDEX_SECOND_CONSTRAINTID 6
                         sep->addChild(new SoInfo());
-                        }
+                    }
                 }
 
                 edit->vConstrType.push_back((*it)->Type);