From 7128cf7989baba2abd83f7816ab4fb3dc8c3f569 Mon Sep 17 00:00:00 2001
From: "Zheng, Lei" <realthunder.dev@gmail.com>
Date: Fri, 23 Aug 2019 19:10:58 +0800
Subject: [PATCH] Sketcher: fix lost of constraint in undo/redo

---
 src/Mod/Sketcher/App/SketchObject.cpp       | 11 ++++-------
 src/Mod/Sketcher/Gui/ViewProviderSketch.cpp | 10 ++++++++++
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/src/Mod/Sketcher/App/SketchObject.cpp b/src/Mod/Sketcher/App/SketchObject.cpp
index 9a3ad5ea9f..2a9d407239 100644
--- a/src/Mod/Sketcher/App/SketchObject.cpp
+++ b/src/Mod/Sketcher/App/SketchObject.cpp
@@ -176,6 +176,7 @@ App::DocumentObjectExecReturn *SketchObject::execute(void)
     // setup and diagnose the sketch
     try {
         rebuildExternalGeometry();
+        Constraints.acceptGeometry(getCompleteGeometry());
     }
     catch (const Base::Exception& e) {
         Base::Console().Error("%s\nClear constraints to external geometry\n", e.what());
@@ -912,9 +913,7 @@ int SketchObject::delGeometry(int GeoId, bool deleteinternalgeo)
     }
 
     this->Geometry.setValues(newVals);
-    this->Constraints.setValues(newConstraints);
-    for (Constraint* it : newConstraints)
-        delete it;
+    this->Constraints.setValues(std::move(newConstraints));
     this->Constraints.acceptGeometry(getCompleteGeometry());
     rebuildVertexIndex();
 
@@ -5357,9 +5356,7 @@ int SketchObject::delExternal(int ExtGeoId)
     }
 
     solverNeedsUpdate=true;
-    Constraints.setValues(newConstraints);
-    for (Constraint* it : newConstraints)
-        delete it;
+    Constraints.setValues(std::move(newConstraints));
     Constraints.acceptGeometry(getCompleteGeometry());
     rebuildVertexIndex();
     return 0;
@@ -5429,7 +5426,7 @@ int SketchObject::delConstraintsToExternal()
         }
     }
 
-    Constraints.setValues(newConstraints);
+    Constraints.setValues(std::move(newConstraints));
     Constraints.acceptGeometry(getCompleteGeometry());
 
     if(noRecomputes) // if we do not have a recompute, the sketch must be solved to update the DoF of the solver
diff --git a/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp b/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp
index 1db7dea438..a70daf4bf1 100644
--- a/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp
+++ b/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp
@@ -4327,6 +4327,16 @@ Restart:
             SoSeparator *sep = static_cast<SoSeparator *>(edit->constrGroup->getChild(i));
             const Constraint *Constr = *it;
 
+            if(Constr->First < -extGeoCount || Constr->First >= intGeoCount 
+                    || (Constr->Second!=Constraint::GeoUndef 
+                        && (Constr->Second < -extGeoCount || Constr->Second >= intGeoCount))
+                    || (Constr->Third!=Constraint::GeoUndef 
+                        && (Constr->Third < -extGeoCount || Constr->Third >= intGeoCount)))
+            {
+                // Constraint can refer to non-existent geometry during undo/redo
+                continue;
+            }
+
             // distinquish different constraint types to build up
             switch (Constr->Type) {
                 case Block: