From efb10e1b288c9607b9eb7743d8d26a82cbaa8aaa Mon Sep 17 00:00:00 2001
From: pjcreath <pjcreath@users.noreply.github.com>
Date: Thu, 20 Nov 2025 15:04:08 -0500
Subject: [PATCH] Sketcher: prevent undo/redo crash when selected geometry goes
 away.

Fixes #25497
---
 src/Mod/Sketcher/Gui/CommandSketcherBSpline.cpp | 3 +++
 src/Mod/Sketcher/Gui/Utils.cpp                  | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/Mod/Sketcher/Gui/CommandSketcherBSpline.cpp b/src/Mod/Sketcher/Gui/CommandSketcherBSpline.cpp
index e56ba9399c..7079ea7aff 100644
--- a/src/Mod/Sketcher/Gui/CommandSketcherBSpline.cpp
+++ b/src/Mod/Sketcher/Gui/CommandSketcherBSpline.cpp
@@ -359,6 +359,9 @@ bool isCommandNeedingBSplineKnotActive(Gui::Document* doc)
         }
 
         auto* Obj = static_cast<Sketcher::SketchObject*>(sel[0].getObject());
+        if (!Obj) {
+            return false;
+        }
         const std::string& name = names[0];
 
         int geoId {GeoEnum::GeoUndef};
diff --git a/src/Mod/Sketcher/Gui/Utils.cpp b/src/Mod/Sketcher/Gui/Utils.cpp
index 592ac74f13..042843e91e 100644
--- a/src/Mod/Sketcher/Gui/Utils.cpp
+++ b/src/Mod/Sketcher/Gui/Utils.cpp
@@ -355,7 +355,7 @@ bool SketcherGui::isBsplineKnotOrEndPoint(
 
     const Part::Geometry* geo = Obj->getGeometry(GeoId);
     // end points of B-Splines are also knots
-    if (geo->is<Part::GeomBSplineCurve>()
+    if (geo && geo->is<Part::GeomBSplineCurve>()
         && (PosId == Sketcher::PointPos::start || PosId == Sketcher::PointPos::end)) {
         return true;
     }