[graphics/krita/krita/6.0] libs/flake: Do not create a new path shape in KoMultiPathPointMergeCommand::redo() call

Git commit 478ddf4e6e5cebe3dbe0473d88d239c28e89ad01 by Dmitry Kazakov, on behalf of Elena Sagalaeva.
Committed on 27/07/2026 at 11:59.
Pushed by dkazakov into branch 'krita/6.0'.

Do not create a new path shape in KoMultiPathPointMergeCommand::redo() call

The subsequent operations don't know about the new shape and continue to
use the old one, which causes crashes.

BUG:523070

M  +26   -20   libs/flake/commands/KoMultiPathPointMergeCommand.cpp
M  +63   -0    libs/flake/tests/TestPointMergeCommand.cpp
M  +3    -0    libs/flake/tests/TestPointMergeCommand.h

https://invent.kde.org/graphics/krita/-/commit/478ddf4e6e5cebe3dbe0473d88d239c28e89ad01

diff --git a/libs/flake/commands/KoMultiPathPointMergeCommand.cpp b/libs/flake/commands/KoMultiPathPointMergeCommand.cpp
index 86b15ce7367..f0c18f6f929 100644
--- a/libs/flake/commands/KoMultiPathPointMergeCommand.cpp
+++ b/libs/flake/commands/KoMultiPathPointMergeCommand.cpp
@@ -51,30 +51,38 @@ KUndo2Command *KoMultiPathPointMergeCommand::createMergeCommand(const KoPathPoin
 
 void KoMultiPathPointMergeCommand::redo()
 {
-    KoShape *mergedShape = 0;
-
-    if (m_d->pointData1.pathShape != m_d->pointData2.pathShape) {
-        KIS_SAFE_ASSERT_RECOVER_RETURN(m_d->controller);
-
-        QList<KoPathShape*> shapes = {m_d->pointData1.pathShape, m_d->pointData2.pathShape};
-        m_d->combineCommand.reset(new KoPathCombineCommand(m_d->controller, shapes));
-        m_d->combineCommand->redo();
-
-        KoPathPointData newPD1 = m_d->combineCommand->originalToCombined(m_d->pointData1);
-        KoPathPointData newPD2 = m_d->combineCommand->originalToCombined(m_d->pointData2);
+    // Create shapes during the first call only.
+    if (!m_d->mergeCommand && !m_d->combineCommand)
+    {
+        if (m_d->pointData1.pathShape != m_d->pointData2.pathShape) {
+            KIS_SAFE_ASSERT_RECOVER_RETURN(m_d->controller);
 
-        m_d->mergeCommand.reset(createMergeCommand(newPD1, newPD2));
-        m_d->mergeCommand->redo();
+            QList<KoPathShape*> shapes = { m_d->pointData1.pathShape, m_d->pointData2.pathShape };
+            m_d->combineCommand.reset(new KoPathCombineCommand(m_d->controller, shapes));
+            
+            KoPathPointData newPD1 = m_d->combineCommand->originalToCombined(m_d->pointData1);
+            KoPathPointData newPD2 = m_d->combineCommand->originalToCombined(m_d->pointData2);
 
-        mergedShape = m_d->combineCommand->combinedPath();
+            m_d->mergeCommand.reset(createMergeCommand(newPD1, newPD2));
+        }
+        else {
+            m_d->mergeCommand.reset(createMergeCommand(m_d->pointData1, m_d->pointData2));
+        }
+    }
 
-    } else {
-        m_d->mergeCommand.reset(createMergeCommand(m_d->pointData1, m_d->pointData2));
+    KoShape *mergedShape = 0;
+    if (m_d->mergeCommand)
+    {
         m_d->mergeCommand->redo();
-
         mergedShape = m_d->pointData1.pathShape;
     }
 
+    if (m_d->combineCommand)
+    {
+        m_d->combineCommand->redo();
+        mergedShape = m_d->combineCommand->combinedPath();
+    }
+ 
     if (m_d->selection) {
         m_d->selection->select(mergedShape);
     }
@@ -92,13 +100,11 @@ void KoMultiPathPointMergeCommand::undo()
     KUndo2Command::undo();
 
     if (m_d->mergeCommand) {
-            m_d->mergeCommand->undo();
-            m_d->mergeCommand.reset();
+        m_d->mergeCommand->undo();
     }
 
     if (m_d->combineCommand) {
         m_d->combineCommand->undo();
-        m_d->combineCommand.reset();
     }
 
     if (m_d->selection) {
diff --git a/libs/flake/tests/TestPointMergeCommand.cpp b/libs/flake/tests/TestPointMergeCommand.cpp
index 38e6481af3f..4eb0f324e0a 100644
--- a/libs/flake/tests/TestPointMergeCommand.cpp
+++ b/libs/flake/tests/TestPointMergeCommand.cpp
@@ -554,6 +554,69 @@ void TestPointMergeCommand::testMultipathJoinShapesSingleShapeStartToEnd()
              }, true);
 }
 
+#include "KoShapeDeleteCommand.h"
 
+void TestPointMergeCommand::undoRedo()
+{
+    KoPathShape path1, path2;
+    path1.moveTo(QPointF(40, 0));
+    path1.lineTo(QPointF(60, 0));
+
+    path2.lineTo(QPointF(60, 30));
+    path2.lineTo(QPointF(0, 30));
+    
+    KoPathPointIndex index1(0, 0);
+    KoPathPointIndex index2(0, 0);
+
+    MockShapeController mockController;
+    MockCanvas canvas(&mockController);
+    MockContainer container1(nullptr);
+
+    path1.setParent(&container1);
+    path2.setParent(&container1);
+
+    KoPathPointData pd1(&path1, index1);
+    KoPathPointData pd2(&path2, index2);
+
+    // Test merge
+    {
+        KoMultiPathPointMergeCommand cmd(pd1, pd2, &mockController, canvas.shapeManager()->selection());
+        cmd.redo();
+
+        KoShapeDeleteCommand  deleteCommand(&mockController, cmd.testingCombinedPath());
+        deleteCommand.redo();
+
+        deleteCommand.undo();
+        cmd.undo();
+
+        cmd.redo();
+        deleteCommand.redo();
+
+        deleteCommand.undo();
+        cmd.undo();
+    }
+
+
+    // Test join
+    {
+        KoMultiPathPointJoinCommand cmd(pd1, pd2, &mockController, canvas.shapeManager()->selection());
+        cmd.redo();
+
+        KoShapeDeleteCommand  deleteCommand(&mockController, cmd.testingCombinedPath());
+        deleteCommand.redo();
+
+        deleteCommand.undo();
+        cmd.undo();
+
+        cmd.redo();
+        deleteCommand.redo();
+
+        deleteCommand.undo();
+        cmd.undo();
+    }
+
+    path1.setParent(nullptr);
+    path2.setParent(nullptr);
+}
 
 KISTEST_MAIN(TestPointMergeCommand)
diff --git a/libs/flake/tests/TestPointMergeCommand.h b/libs/flake/tests/TestPointMergeCommand.h
index 0184c628ac1..95e32e0ef6a 100644
--- a/libs/flake/tests/TestPointMergeCommand.h
+++ b/libs/flake/tests/TestPointMergeCommand.h
@@ -35,6 +35,9 @@ private Q_SLOTS:
     void testMultipathJoinShapesSingleShapeEndToStart();
     void testMultipathJoinShapesSingleShapeStartToEnd();
 
+    // Regression test. Making sure that undo/redo operations don't cause crashes.
+    void undoRedo();
+
 };
 
 #endif // TESTPOINTMERGECOMMAND_H