Callback deadlock

[Matthew J. Francis]

On 29/06/2015 15:47, Piet van Oostrum wrote:
> It is not completely clear if you are calling from a remote Python program, or from inside LO.
> Assuming that it is remote, yes, there are problems with listeners in this situation. It can easily deadlock. I have posted a similar situation on this list some months ago, where I did a paragraph enumeration in a listener callback and it also deadlocked. See lists.freedesktop.org/archives/libreoffice/2015-April/067601.html
>
> Basically the conclusion was the LO does too much locking here, but that it could not be avoided because of severe problems if it wouldn't lock.

It's remote - a test running as an external process.

The Python side of the deadlock is http://pastebin.com/qPkyVTkk
(this is a different run - the corresponding soffice.bin trace is 
http://pastebin.com/g4F8zcUi )

The two things that seem to be happening are:

In thread 1, the main Python thread has got the Text property for the 
text document being worked on, and PyUNO_new_UNCHECKED() is called to 
make a Python object for the result, which calls 
createInstanceWithArguments()

Meanwhile, in thread 2, the windowActivated() callback bas been 
received, and pyuno::PyUNO_new_UNCHECKED() is called to make a Python 
object for the argument, which calls createInstanceWithArguments()


If this sequence doesn't work, I'm not sure what if anything the Python 
side can do better here.

Regards
Matthew Francis