From 67df9301842517dd4d3aa5bf2e2c5ec2b91a29a8 Mon Sep 17 00:00:00 2001
From: jack9603301 <jack9603301@163.com>
Date: Thu, 14 Oct 2021 03:43:20 +0800
Subject: [PATCH] [Part] Fix null pointer error in sweep operation

When the spine line of the sweep operation of the part workbench depends
on the Sketcher document, if the dependent spine line drawn by this document
is deleted afterwards, the path variable will get a null pointer.
Due to programming errors, the standard judgment of this pointer is ignored, resulting in a crash.
Call IsNull() of the OCC document to determine the legitimacy of the shape.
If it is empty, an error is reported.

Fixes #0004764
---
 src/Mod/Part/App/PartFeatures.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/Mod/Part/App/PartFeatures.cpp b/src/Mod/Part/App/PartFeatures.cpp
index 4d9e1fc0f9..469dc4a22e 100644
--- a/src/Mod/Part/App/PartFeatures.cpp
+++ b/src/Mod/Part/App/PartFeatures.cpp
@@ -544,6 +544,10 @@ App::DocumentObjectExecReturn *Sweep::execute(void)
                 break;
         }
 
+        if(path.IsNull()) {
+            return new App::DocumentObjectExecReturn("Spine path missing, sweep operation stopped.");
+        }
+
         if (path.ShapeType() == TopAbs_EDGE) {
             BRepBuilderAPI_MakeWire mkWire(TopoDS::Edge(path));
             path = mkWire.Wire();