Avoid a segfault: an event may kill the event object itself indirectly.

src/pya/unit_tests/pyaTests.cc

@@ -106,6 +106,7 @@ PYTHONTEST (dbLayoutToNetlist, "dbLayoutToNetlist.py")
 PYTHONTEST (dbLayoutVsSchematic, "dbLayoutVsSchematic.py")
 PYTHONTEST (dbNetlistCrossReference, "dbNetlistCrossReference.py")
 PYTHONTEST (layLayers, "layLayers.py")
+PYTHONTEST (layObjects, "layObjects.py")
 PYTHONTEST (layPixelBuffer, "layPixelBuffer.py")
 PYTHONTEST (tlTest, "tlTest.py")
 #if defined(HAVE_QT) && defined(HAVE_QTBINDINGS)

src/tl/tl/tlEventsVar.h

@@ -175,8 +175,26 @@ public:
   typedef typename receivers::iterator receivers_iterator;
 #endif
 
+  event<_TMPLARGLISTP> ()
+    : mp_destroyed_sentinel (0)
+  {
+    //  .. nothing yet ..
+  }
+
+  ~event<_TMPLARGLISTP> ()
+  {
+    if (mp_destroyed_sentinel) {
+      *mp_destroyed_sentinel = true;
+    }
+    mp_destroyed_sentinel = 0;
+  }
+
   void operator() (_CALLARGLIST)
   {
+    bool was_destroyed = false;
+    bool *org_sentinel = mp_destroyed_sentinel;
+    mp_destroyed_sentinel = &was_destroyed;
+
     //  Issue the events. Because inside the call, other receivers might be added, we make a copy
     //  first. This way added events won't be called now.
     receivers tmp_receivers = m_receivers;
@@ -184,6 +202,10 @@ public:
       if (r->first.get ()) {
         try {
           r->second->call (_JOIN(r->first.get (), _CALLARGS));
+          if (was_destroyed) {
+            //  during the call something deleted us. Stop immediately.
+            return;
+          }
         } catch (tl::Exception &ex) {
           handle_event_exception (ex);
         } catch (std::exception &ex) {
@@ -194,6 +216,8 @@ public:
       }
     }
 
+    mp_destroyed_sentinel = org_sentinel;
+
     //  Clean up expired entries afterwards (the call may have expired them)
     receivers_iterator w = m_receivers.begin ();
     for (receivers_iterator r = m_receivers.begin (); r != m_receivers.end (); ++r) {
@@ -339,6 +363,7 @@ public:
   }
 
 private:
+  bool *mp_destroyed_sentinel;
   receivers m_receivers;
 };
 

testdata/python/layObjects.py

@@ -0,0 +1,54 @@
+# 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 pya
+import unittest
+
+class LAYObjectsTests(unittest.TestCase):
+
+  def test_1(self):
+
+    class MyBrowserSource(pya.BrowserSource):
+      def get(self, url):
+        next_url = "int:" + str(int(url.split(":")[1]) + 1)
+        return f"This is {url}. <a href='{next_url}'>Goto next ({next_url})</a>"
+      
+    dialog = pya.BrowserDialog()
+    dialog.home = "int:0"
+    dialog.source = MyBrowserSource()
+
+    dialog = pya.BrowserDialog()
+    dialog.home = "int:0"
+    dialog.source = MyBrowserSource()
+
+    self.assertEqual(True, True)
+
+
+# run unit tests
+if __name__ == '__main__':
+  suite = unittest.TestSuite()
+  # NOTE: Use this instead of loadTestsfromTestCase to select a specific test:
+  #   suite.addTest(BasicTest("test_26"))
+  suite = unittest.TestLoader().loadTestsFromTestCase(LAYObjectsTests)
+
+  # Only runs with Application available
+  if "Application" in pya.__all__ and not unittest.TextTestRunner(verbosity = 1).run(suite).wasSuccessful():
+    sys.exit(1)
+
+
+