From 63a4fe8d7744a9aed1a064d6e245e0d18170e406 Mon Sep 17 00:00:00 2001
From: Matthias Koefferlein <matthias@klayout.de>
Date: Fri, 7 Apr 2023 10:59:30 +0200
Subject: [PATCH] Issue #1327 fixed (segfault in pymod finalization code)

---
 src/db/db/dbLayout.h                | 12 ++++++------
 src/pymod/unit_tests/pymod_tests.cc |  6 ++++++
 testdata/pymod/issue1327.py         | 28 ++++++++++++++++++++++++++++
 3 files changed, 40 insertions(+), 6 deletions(-)
 create mode 100755 testdata/pymod/issue1327.py

diff --git a/src/db/db/dbLayout.h b/src/db/db/dbLayout.h
index 87f76b965..232f52465 100644
--- a/src/db/db/dbLayout.h
+++ b/src/db/db/dbLayout.h
@@ -1952,7 +1952,7 @@ public:
   explicit LayoutLocker (db::Layout *layout = 0, bool no_update = false)
     : mp_layout (layout), m_no_update (no_update)
   {
-    if (mp_layout) {
+    if (mp_layout.get ()) {
       mp_layout->start_changes ();
     }
   }
@@ -1965,7 +1965,7 @@ public:
   LayoutLocker (const LayoutLocker &other)
     : mp_layout (other.mp_layout), m_no_update (other.m_no_update)
   {
-    if (mp_layout) {
+    if (mp_layout.get ()) {
       mp_layout->start_changes ();
     }
   }
@@ -1976,17 +1976,17 @@ public:
       return *this;
     }
 
-    set (other.mp_layout, other.m_no_update);
+    set (const_cast<db::Layout *> (other.mp_layout.get ()), other.m_no_update);
     return *this;
   }
 
 private:
-  db::Layout *mp_layout;
+  tl::weak_ptr<db::Layout> mp_layout;
   bool m_no_update;
 
   void set (db::Layout *layout, bool no_update)
   {
-    if (mp_layout) {
+    if (mp_layout.get ()) {
       if (m_no_update) {
         mp_layout->end_changes_no_update ();
       } else {
@@ -1995,7 +1995,7 @@ private:
     }
     mp_layout = layout;
     m_no_update = no_update;
-    if (mp_layout) {
+    if (mp_layout.get ()) {
       mp_layout->start_changes ();
     }
   }
diff --git a/src/pymod/unit_tests/pymod_tests.cc b/src/pymod/unit_tests/pymod_tests.cc
index 733143794..d523dd344 100644
--- a/src/pymod/unit_tests/pymod_tests.cc
+++ b/src/pymod/unit_tests/pymod_tests.cc
@@ -71,6 +71,9 @@ int run_pymodtest (tl::TestBase *_this, const std::string &fn)
     tl::InputPipe pipe (cmd);
     tl::InputStream is (pipe);
     text = is.read_all ();
+
+    //  subprocess exits without error
+    EXPECT_EQ (pipe.wait(), 0);
   }
 
   tl::info << text;
@@ -89,6 +92,9 @@ PYMODTEST (import_db, "import_db.py")
 PYMODTEST (import_rdb, "import_rdb.py")
 PYMODTEST (import_lay, "import_lay.py")
 
+//  others
+PYMODTEST (issue1327, "issue1327.py")
+
 #if defined(HAVE_QT) && defined(HAVE_QTBINDINGS)
 
 PYMODTEST (import_QtCore, "import_QtCore.py")
diff --git a/testdata/pymod/issue1327.py b/testdata/pymod/issue1327.py
new file mode 100755
index 000000000..b6a4fbed5
--- /dev/null
+++ b/testdata/pymod/issue1327.py
@@ -0,0 +1,28 @@
+# KLayout Layout Viewer
+# Copyright (C) 2006-2023 Matthias Koefferlein
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+import klayout.db as kdb
+
+ly = kdb.Layout()
+cell = ly.create_cell("TOP")
+parents = cell.each_parent_cell()
+
+# makes the unit test happy
+print("OK")
+
+# was crashing now in finalization code ..
+