deferred-chain was in kept in scope by a consumer-operation, this fixes #323

include/amqpcpp/channelimpl.h

@@ -5,7 +5,7 @@
  *  that has a private constructor so that it can not be used from outside
  *  the AMQP library
  *
- *  @copyright 2014 - 2018 Copernica BV
+ *  @copyright 2014 - 2020 Copernica BV
  */
 
 /**
@@ -658,9 +658,14 @@ public:
         // call the callback
         auto next = cb->reportSuccess(std::forward<Arguments>(parameters)...);
 
-        // leap out if channel no longer exists
+        // leap out if channel no longer exist
         if (!monitor.valid()) return false;
         
+        // in case the callback-shared-pointer is still kept in scope (for example because it
+        // is stored in the list of consumers), we do want to ensure that it no longer maintains
+        // a chain of queued deferred objects
+        cb->unchain();
+
         // set the oldest callback
         _oldestCallback = next;
 
@@ -729,8 +734,8 @@ public:
     DeferredPublisher *publisher() const { return _publisher.get(); }
 
     /**
-     * Retrieve the deferred confirm that handles publisher confirms
+     *  Retrieve the deferred confirm that handles publisher confirms
-     * @return The deferred confirm object
+     *  @return The deferred confirm object
      */
     DeferredConfirm *confirm() const { return _confirm.get(); }
 

include/amqpcpp/deferred.h

@@ -5,7 +5,7 @@
  *  possibly happen in the future that can be
  *  caught.
  *
- *  @copyright 2014 - 2018 Copernica BV
+ *  @copyright 2014 - 2020 Copernica BV
  */
 
 /**
@@ -179,6 +179,15 @@ protected:
         _next = deferred;
     }
     
+    /**
+     *  Remove this object from the chain of deferreds
+     */
+    void unchain()
+    {
+        // we no longer need the next pointer
+        _next = nullptr;
+    }
+
     /**
      *  The channel implementation may call our
      *  private members and construct us

src/channelimpl.cpp

@@ -3,7 +3,7 @@
  *
  *  Implementation for a channel
  *
- *  @copyright 2014 - 2018 Copernica BV
+ *  @copyright 2014 - 2020 Copernica BV
  */
 #include "includes.h"
 #include "basicgetokframe.h"
@@ -816,6 +816,11 @@ void ChannelImpl::reportError(const char *message, bool notifyhandler)
         // leap out if channel no longer exists
         if (!monitor.valid()) return;
 
+        // in case the callback-shared-pointer is still kept in scope (for example because it
+        // is stored in the list of consumers), we do want to ensure that it no longer maintains
+        // a chain of queued deferred objects
+        cb->unchain();
+
         // set the oldest callback
         _oldestCallback = next;
     }
@@ -833,6 +838,11 @@ void ChannelImpl::reportError(const char *message, bool notifyhandler)
         // leap out if channel no longer exists
         if (!monitor.valid()) return;
 
+        // in case the callback-shared-pointer is still kept in scope (for example because it
+        // is stored in the list of consumers), we do want to ensure that it no longer maintains
+        // a chain of queued deferred objects
+        cb->unchain();
+
         // set the oldest callback
         _oldestCallback = next;
     }