From 4d712f44c220eac90c26afe4eb1c41b4f2f403c6 Mon Sep 17 00:00:00 2001
From: Kacper Donat <kacper@kadet.net>
Date: Mon, 22 Dec 2025 12:52:55 +0100
Subject: [PATCH] PartDesign: Chamfer - migrate Size and Size2 for older files
 (#26137)

* PartDesign: Chamfer - migrate Size and Size2 for older files

* Apply suggestions from code review

Co-authored-by: Chris Hennes <chennes@pioneerlibrarysystem.org>

---------

Co-authored-by: Chris Hennes <chennes@pioneerlibrarysystem.org>
---
 src/Mod/PartDesign/App/FeatureChamfer.cpp | 27 +++++++++++++++++++++++
 src/Mod/PartDesign/App/FeatureChamfer.h   |  3 +++
 2 files changed, 30 insertions(+)

diff --git a/src/Mod/PartDesign/App/FeatureChamfer.cpp b/src/Mod/PartDesign/App/FeatureChamfer.cpp
index 47e6b5351e..fdec798ade 100644
--- a/src/Mod/PartDesign/App/FeatureChamfer.cpp
+++ b/src/Mod/PartDesign/App/FeatureChamfer.cpp
@@ -41,6 +41,8 @@
 
 #include "FeatureChamfer.h"
 
+#include <Base/ProgramVersion.h>
+
 
 using namespace PartDesign;
 
@@ -205,6 +207,8 @@ App::DocumentObjectExecReturn* Chamfer::execute()
 void Chamfer::Restore(Base::XMLReader& reader)
 {
     DressUp::Restore(reader);
+
+    migrateFlippedProperties(reader);
 }
 
 void Chamfer::handleChangedPropertyType(Base::XMLReader& reader, const char* TypeName, App::Property* prop)
@@ -220,6 +224,29 @@ void Chamfer::handleChangedPropertyType(Base::XMLReader& reader, const char* Typ
     }
 }
 
+bool Chamfer::requiresSizeSwapping(const Base::XMLReader& reader) const
+{
+    return Base::getVersion(reader.ProgramVersion) < Base::Version::v1_0
+        && (ChamferType.getValue() == 1 || ChamferType.getValue() == 2);
+}
+
+void Chamfer::migrateFlippedProperties(const Base::XMLReader& reader)
+{
+    if (!requiresSizeSwapping(reader)) {
+        return;
+    }
+
+    Base::Console().warning(
+        "The 'FlipDirection' property of the chamfer of %s is being adjusted to maintain"
+        "the same geometry in this FreeCAD version. If the re-saved file is later opened "
+        "in FreeCAD 0.21.x the chamfer result may differ due to the changed parameter "
+        "interpretation.\n",
+        getFullName()
+    );
+
+    FlipDirection.setValue(!FlipDirection.getValue());
+}
+
 void Chamfer::onChanged(const App::Property* prop)
 {
     if (prop == &ChamferType) {
diff --git a/src/Mod/PartDesign/App/FeatureChamfer.h b/src/Mod/PartDesign/App/FeatureChamfer.h
index ccaca0f10f..a11f3637cb 100644
--- a/src/Mod/PartDesign/App/FeatureChamfer.h
+++ b/src/Mod/PartDesign/App/FeatureChamfer.h
@@ -70,6 +70,9 @@ protected:
     ) override;
     static const App::PropertyQuantityConstraint::Constraints floatSize;
     static const App::PropertyAngle::Constraints floatAngle;
+
+    bool requiresSizeSwapping(const Base::XMLReader& reader) const;
+    void migrateFlippedProperties(const Base::XMLReader& reader);
 };
 
 }  // namespace PartDesign