Problem/Bug? with dbus-daemon

[David Belser]

I have a C++ app that pushes a lot of message through the dbus-daemon.
I'm getting errors from the daemon - "The maximum number of pending
replies per connection has been reached"

The problem appears to be in bus/connection.c - I found where the
message is originated and added a _dbus_verbose to print the count of
pending replies. The result is that the count just continues to
increase. After going over the code and looking at verbose output here
is what I found:

I see the pending calls being added in bus_connections_expect_reply.
I also see that cancel_pending_reply_data_free is being called via
bus_transaction_execute_and_free - where it calls free_cancel_hooks.

If I read it correctly, the pending reply gets added to a list for the
connection in bus_connections_expect_reply. At the same time it adds
cancel hooks - cancel_pending_reply and cancel_pending_reply_data_free
to the transaction. When bus_transaction_execute_and_free gets called,
it calls free_cancel_hooks which released the data for the pending
reply but it doesn't remove it from the pending reply list. So the
list continues to grow with pending replies that have been free'd.

As an experiment, I changed both of the cancel hook functions to be -
cancel_pending_reply - which both removes the reply from the list and
also frees the reply.

So maybe it's assumed that the reply will be removed before or when
the transaction executes so freeing just data in the cancel hooks
would be OK. But looking thru the code I can only find 2 places that
pending replies are removed from the list:

- bus_pending_reply_expired, which is clearly not the case here, the
replies are immediate
- bus_connection_drop_pending_replies, only called from
bus_connection_disconnected which is
also not happening in my case.

This happens in both 1.1.20 and 1.2.1
I noticed that there was rework done on connection.c for the bus
expire list so I verified that I have the same problem with both
versions.

Is this a bug? I'd be surprised if it is. In the normal case where are
pending replies supposed to be removed?

Dave