[libvirt] Missing blockJobInfo() method from v1.2.5 Python bindings?

[Michal Privoznik]

On 04.10.2016 10:43, Kashyap Chamarthy wrote:
> Last night I was trying to check whether blockJobInfo() method will
> raise an error when it returns 'None' in v1.2.5 libvirt Python bindings.
> (Eric Blake confirmed on IRC: "the python bindings have, as a general
> rule, always raised a libvirtError if the C binding code returns None").
> 
> Before asking on IRC, I built the bindings and the below is what I noticed.
> 
> Let's first see what's in current Git master:
> 
>     $ less build/libvirt.py
>     [...]
>     def blockJobInfo(self, path, flags=0):
>         """Get progress information for a block job """
>         ret = libvirtmod.virDomainGetBlockJobInfo(self._o, path, flags)
>         if ret is None: raise libvirtError ('virDomainGetBlockJobInfo() failed', dom=self)
>         return ret
>     [...]
> 
> Now try to find out what is present in v1.2.5 by quickly building the
> bindings for that tag:
> 
>     $ git checkout v1.2.5
>     $ python setup.py build
> 
> Hmm, once built, there's no blockJobInfo() method in build/libvirt.py!
> (When I mentioned this on #virt, OFTC, Cole confirmed he could reproduce
> the behavior, too.  Not sure if it's a regression in v1.2.5.)

I've bisected this one down to 8e09c79a07b097a6ba9af83be4916fb9c9538500:

$ git describe --contains 8e09c79a07b097a6ba9af83be4916fb9c9538500
v1.2.10^0

It's a result of a split of python bindings we made a long time ago.

> 
> However, the libvirt "glue code" for libvirt_virDomainGetBlockJobInfo()
> exists in libvirt-python/libvirt-override.c, so checking there (again,
> for v1.2.5), we see:
> 
>    4755     if (c_ret == 0) {
>    4756         return dict;
>    4757     } else if (c_ret < 0) {
>    4758         Py_DECREF(dict);
>    4759         return VIR_PY_NONE;
>    4760     }
> 
> IIUC, the VIR_PY_NONE means it raises an exception (libvirtError).
> 

Correct, the exception is raised in C API fails. Note, that it is not
considered a failure if there's no job running (in which case an empty
dict is returned).

Michal