From f10ccfc0fbe416fc853da6057bd51fd4e90c86f3 Mon Sep 17 00:00:00 2001
From: Ajinkya Dahale <AjinkyaDahale@users.noreply.github.com>
Date: Tue, 8 Mar 2022 05:28:01 -0500
Subject: [PATCH] [Sketcher] Safeguard against spurious pre-selection

Preselection is sometimes not updated under some circumstances
1. when deleting an object through python;
2. before autoconstraint when deleting previous pole in bspline creation mode.

When the preselected curve is the deleted object, segfault/crash can happen.
---
 src/Mod/Sketcher/Gui/DrawSketchHandler.cpp          | 13 ++++++++-----
 .../Sketcher/Gui/EditModeGeometryCoinManager.cpp    |  4 +++-
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/Mod/Sketcher/Gui/DrawSketchHandler.cpp b/src/Mod/Sketcher/Gui/DrawSketchHandler.cpp
index 2edd655d94..d67bda66fc 100644
--- a/src/Mod/Sketcher/Gui/DrawSketchHandler.cpp
+++ b/src/Mod/Sketcher/Gui/DrawSketchHandler.cpp
@@ -411,12 +411,15 @@ int DrawSketchHandler::seekAutoConstraint(std::vector<AutoConstraint> &suggested
     if (preSelPnt != -1)
         sketchgui->getSketchObject()->getGeoVertexIndex(preSelPnt, GeoId, PosId);
     else if (preSelCrv != -1){
-        GeoId = preSelCrv;
-        const Part::Geometry *geom = sketchgui->getSketchObject()->getGeometry(GeoId);
+        const Part::Geometry *geom = sketchgui->getSketchObject()->getGeometry(preSelCrv);
 
-        if(geom->getTypeId() == Part::GeomLineSegment::getClassTypeId()){
-            const Part::GeomLineSegment *line = static_cast<const Part::GeomLineSegment *>(geom);
-            hitShapeDir= line->getEndPoint()-line->getStartPoint();
+        // ensure geom exists in case object was called before preselection is updated
+        if (geom) {
+            GeoId = preSelCrv;
+            if (geom->getTypeId() == Part::GeomLineSegment::getClassTypeId()) {
+                const Part::GeomLineSegment *line = static_cast<const Part::GeomLineSegment *>(geom);
+                hitShapeDir= line->getEndPoint()-line->getStartPoint();
+            }
         }
 
     }
diff --git a/src/Mod/Sketcher/Gui/EditModeGeometryCoinManager.cpp b/src/Mod/Sketcher/Gui/EditModeGeometryCoinManager.cpp
index 6c145101b0..5dae35b766 100644
--- a/src/Mod/Sketcher/Gui/EditModeGeometryCoinManager.cpp
+++ b/src/Mod/Sketcher/Gui/EditModeGeometryCoinManager.cpp
@@ -303,7 +303,9 @@ void EditModeGeometryCoinManager::updateGeometryColor(const GeoListFacade & geol
         }
         else if (preselectpoint != -1) {
             preselectpointmfid = coinMapping.getIndexLayer(preselectpoint);
-            if (l == preselectpointmfid.layerId && preselectpointmfid.fieldIndex < PtNum)
+            if (MultiFieldId::Invalid != preselectpointmfid &&
+                preselectpointmfid.layerId == l &&
+                preselectpointmfid.fieldIndex < PtNum)
                 pcolor[preselectpointmfid.fieldIndex] = drawingParameters.PreselectColor;
         }