[libvirt] [PATCH python] Fix handling of optional params in blockCopy()

[Daniel P. Berrangé]

On Sun, Mar 10, 2019 at 03:03:25AM +0200, Nir Soffer wrote:
> Commit 2b4bd07e0a22 (Add check for params, nparams being a dictionary)
> changed the way the optional params argument is treated. If
> libvirt.virDomain.blockCopy() is called without specifying params,
> params is None, and the call will fail with:
> 
>     TypeError: block params must be a dictionary
> 
> This is wrong as params is defined as kwarg, breaking existing libvirt
> users like oVirt. Remove the check, restoring the previous behaviour.
> 
> Resolves: https://bugzilla.redhat.com/1687114
> 
> Signed-off-by: Nir Soffer <nsoffer at redhat.com>
> ---
>  libvirt-override.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/libvirt-override.c b/libvirt-override.c
> index 857c018..127d71c 100644
> --- a/libvirt-override.c
> +++ b/libvirt-override.c
> @@ -8829,19 +8829,17 @@ libvirt_virDomainBlockCopy(PyObject *self ATTRIBUTE_UNUSED,
>  
>      if (!PyArg_ParseTuple(args, (char *) "Ozz|OI:virDomainBlockCopy",
>                            &pyobj_dom, &disk, &destxml, &pyobj_dict, &flags))
>          return NULL;
>  
> +    /* Note: params is optional in libvirt.py */
>      if (PyDict_Check(pyobj_dict)) {
>          if (virPyDictToTypedParams(pyobj_dict, &params, &nparams,
>                                     virPyDomainBlockCopyParams,
>                                     VIR_N_ELEMENTS(virPyDomainBlockCopyParams)) < 0) {
>              return NULL;
>          }
> -    } else {
> -        PyErr_Format(PyExc_TypeError, "block params must be a dictionary");
> -        return NULL;
>      }

Rather than removing this else branch, I think we should have an explict
check for None first

   if (pyobj_dict == Py_None) {
       ...no op..
   } else if (PyDict_Check(....)) {
   } else {
       .... error ...
   }

Can you do that & validate that it works with oVirt.

Regards,
Daniel
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