UITest_writerperfect_epubexport hang (only sometimes)

[Stephan Bergmann]

On 31.01.2018 11:20, Stephan Bergmann wrote:
> On 23.01.2018 09:18, Miklos Vajna wrote:
>> I've added UITest_writerperfect_epubexport a while ago, and while I did
>> not see it hanging in the recent past, both Noel and Stephan run into
>> a hang of it from time to time.
>>
>> The code is here:
>>
>> writerperfect/qa/uitest/epubexport/epubexport.py
>>
>> The backtrace always looks like this:
>> self.ui_test.execute_blocking_action() gets an UNO method where invoking
>> it opens a dialog and the python method also gets a callback. When the
>> hang happens, then it seems the problem is that the Python thread waits
>> for the dialog to be closed, but in fact it's already closed, so it
>> waits forever joining the python thread.
>>
>> I don't think there is anything really special in this test, rather I
>> guess the problem happens here more frequently (than elsewhere) because
>> normally these dialogs are invoked via UNO commands, where we just
>> execute the UNO command, wait for the dialog to appear then work with
>> it. (I did not look at the implementation, perhaps in this case there is
>> no Python thread involved?)
>>
>> So I wonder -- do you think it would be possible or would make sense to
>> have a way similar to self.xUITest.executeCommand (execute a blocking
>> command async), but for UNO methods that open a dialog? I.e. also
>> similar to self.ui_test.execute_blocking_action, but without an actual
>> callback.
>>
>> Perhaps that would be a fix for these strange hangs.
> 
> Is anything blocking this? 
> <https://ci.libreoffice.org/job/lo_gerrit/26790/Config=linux_clang_dbgutil_64/console> 
> is yet another hung Gerrit/Jenkins build that might or might not be 
> caused by this issue.

ping?