Re: pyspi SpiException question

[Zack Cerza <zcerza redhat com>]

Marcin Lyko wrote:
> Hi all,
>
> I have a question about raising SpiException exceptions by Pyspi. Is it
> okey that Pyspi raises SpiException (Non-fatal SPIException: type:0
> source:0 "IDL:omg.org/CORBA/COMM_FAILURE:1.0) during call some method of
> "gets" methods (getName, getRoleName, getComponent, etc) on an
> accessible object of an application that has been already closed? A
> refernce to the accessible object was taken before closing the application.
> Here are example tracebacks:
> $ ./spiexception.py
> Traceback (most recent call last):
>   File "./spiexception.py", line 23, in <module>
>     scan_app(app)
>   File "./spiexception.py", line 10, in scan_app
>     app.getName()
>   File "pyspi.pyx", line 463, in atspi.Accessible.getName
>   File "pyspi.pyx", line 152, in atspi.exception_handler
> atspi.SpiException: Non-fatal SPIException: type:0 source:0
> "IDL:omg.org/CORBA/COMM_FAILURE:1.0"
> ~ $ ./spiexception.py
> Traceback (most recent call last):
>   File "./spiexception.py", line 23, in <module>
>     scan_app(app)
>   File "./spiexception.py", line 15, in scan_app
>     app.getAction()
>   File "pyspi.pyx", line 582, in atspi.Accessible.getAction
>   File "pyspi.pyx", line 152, in atspi.exception_handler
> atspi.SpiException: Non-fatal SPIException: type:0 source:0
> "IDL:omg.org/CORBA/COMM_FAILURE:1.0"
> ~ $ ./spiexception.py
> Traceback (most recent call last):
>   File "./spiexception.py", line 23, in <module>
>     scan_app(app)
>   File "./spiexception.py", line 14, in scan_app
>     app.getComponent()
>   File "pyspi.pyx", line 666, in atspi.Accessible.getComponent
>   File "pyspi.pyx", line 152, in atspi.exception_handler
> atspi.SpiException: Non-fatal SPIException: type:0 source:0
> "IDL:omg.org/CORBA/COMM_FAILURE:1.0"

These are normal and expected in the case where the application 
disappears out from under pyspi.

> I run an application, next I run the spiexception.py, which takes
> reference to the run application and calls getName, gatRoleName,
> getAction, getComponent, etc methods and during running of the script I
> close the application. Every time I get similar errors to these above.
>
> IMHO, these situations are similar to a situation from the bug:
> http://bugzilla.gnome.org/show_bug.cgi?id=468636
> where the same exception was raised inside getChildAtIndex method. Since
> fixing the bug, these exceptions are caught in the method in Pyspi and
> the None object is returned instead. Maybe catching of exceptions should
> be also add to others "gets" methods?

I think it's more appropriate to raise exceptions, since the situation 
is in fact "exceptional" - the methods you're calling assume a valid 
reference, but the reference is no longer valid. I think it's their duty 
to make it very clear what's happening :)

Also, note that pyspi has been obsoleted by pyatspi, the official python 
bindings for AT-SPI. pyatspi is in AT-SPI svn, and dogtail svn has been 
ported to it.

Zack

> P.S. Please add my e-mail address to CC of every responses to this mail,
> thanks in advance!
>
> Best regards,
> Marcin Lyko