From beec19951d84bc79d1b15e22b09137d8038f7ffe Mon Sep 17 00:00:00 2001
From: Matthias Koefferlein <matthias@koefferlein.de>
Date: Sun, 5 Jul 2020 14:09:23 +0200
Subject: [PATCH] Candidate for fix.

---
 src/pya/pya/pyaObject.cc        | 6 +++++-
 src/rba/rba/rbaInternal.cc      | 6 +++++-
 testdata/ruby/basic_testcore.rb | 6 ++++++
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/pya/pya/pyaObject.cc b/src/pya/pya/pyaObject.cc
index c4f8f815c..11ee0be14 100644
--- a/src/pya/pya/pyaObject.cc
+++ b/src/pya/pya/pyaObject.cc
@@ -306,7 +306,11 @@ PYAObjectBase::detach ()
       }
     }
 
-    detach_callbacks ();
+    //  NOTE: m_owned = false might mean the C++ object is already destroyed. We must not
+    //  modify in this case and without is_managed() there is no way of knowing the state.
+    if (m_owned) {
+      detach_callbacks ();
+    }
 
     m_obj = 0;
     m_const_ref = false;
diff --git a/src/rba/rba/rbaInternal.cc b/src/rba/rba/rbaInternal.cc
index 8a7ed7fc2..3ca0c0ea2 100644
--- a/src/rba/rba/rbaInternal.cc
+++ b/src/rba/rba/rbaInternal.cc
@@ -402,7 +402,11 @@ Proxy::detach ()
     }
   }
 
-  clear_callbacks ();
+  //  NOTE: m_owned = false might mean the C++ object is already destroyed. We must not
+  //  modify in this case and without is_managed() there is no way of knowing the state.
+  if (m_owned) {
+    clear_callbacks ();
+  }
 
   m_self = Qnil;
   m_obj = 0;
diff --git a/testdata/ruby/basic_testcore.rb b/testdata/ruby/basic_testcore.rb
index ccacfe280..97e97e794 100644
--- a/testdata/ruby/basic_testcore.rb
+++ b/testdata/ruby/basic_testcore.rb
@@ -1402,6 +1402,12 @@ class Basic_TestClass < TestBase
       a._manage
     end
 
+    # Looks like Ruby is keeping the last A instance in some kind of cache:
+    # this will release it
+    a = RBA::A.new
+    a._destroy
+    a = nil
+
     # makes sure the objects inside the block before are deleted
     GC.start