From 6f048d10c5348a3b3934de5d415628ffd986b04a Mon Sep 17 00:00:00 2001
From: David Capello <david@igarastudio.com>
Date: Wed, 17 Jun 2020 17:13:37 -0300
Subject: [PATCH] lua: Fix crash using Selection:deselect() when there is no
 selection

Fixes https://community.aseprite.org/t/6169
---
 src/app/cmd/deselect_mask.cpp      | 12 +++++++-----
 src/app/script/selection_class.cpp | 10 ++++++----
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/src/app/cmd/deselect_mask.cpp b/src/app/cmd/deselect_mask.cpp
index f661ed751..39da945cf 100644
--- a/src/app/cmd/deselect_mask.cpp
+++ b/src/app/cmd/deselect_mask.cpp
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019  Igara Studio S.A.
+// Copyright (C) 2019-2020  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -35,11 +35,13 @@ void DeselectMask::onUndo()
 {
   Doc* doc = document();
 
-  doc->setMask(m_oldMask.get());
-  doc->setMaskVisible(true);
-  doc->notifySelectionChanged();
+  if (m_oldMask) {
+    doc->setMask(m_oldMask.get());
+    doc->setMaskVisible(true);
+    m_oldMask.reset();
+  }
 
-  m_oldMask.reset();
+  doc->notifySelectionChanged();
 }
 
 size_t DeselectMask::onMemSize() const
diff --git a/src/app/script/selection_class.cpp b/src/app/script/selection_class.cpp
index f30db6080..4426d9030 100644
--- a/src/app/script/selection_class.cpp
+++ b/src/app/script/selection_class.cpp
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2018-2019  Igara Studio S.A.
+// Copyright (C) 2018-2020  Igara Studio S.A.
 // Copyright (C) 2015-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -116,9 +116,11 @@ int Selection_deselect(lua_State* L)
     Doc* doc = static_cast<Doc*>(sprite->document());
     ASSERT(doc);
 
-    Tx tx;
-    tx(new cmd::DeselectMask(doc));
-    tx.commit();
+    if (doc->isMaskVisible()) {
+      Tx tx;
+      tx(new cmd::DeselectMask(doc));
+      tx.commit();
+    }
   }
   else {
     auto mask = obj->mask(L);