[libvirt] [PATCH] Fix virsh snapshot-list error reporting

[Jim Fehlig]

Eric Blake wrote:
> On 07/25/2013 02:38 PM, Jim Fehlig wrote:
>   
>> Noticed that the expected "not supported" error is dropped when
>> invoking 'virsh snapshot-list dom' on a Xen installation running
>> the libxl driver
>>
>>  virsh snapshot-list test
>>  error: Invalid snapshot: virDomainSnapshotFree
>>
>> The error is overwritten by a call to virDomainSnapshotFree
>> in cleanup code within cmdSnapshotList.  Prevent overwritting
>> the real error by not calling virDomainSnapshotFree with a NULL
>> virDomainSnapshotPtr.
>>     
>
> Indeed.
>
>   
>> ---
>>
>> This is one possible fix for the bug.  The other would be to
>> silently return in virDomainSnapshotFree on a NULL
>> virDomainSnapshotPtr.
>>     
>
> No, that would be an incompatible behavior change - our API promises a
> failure on attempting to free a null object, and people have come to
> rely on that.
>   

Ah, yes, good point.

>   
>> +++ b/tools/virsh-snapshot.c
>> @@ -1678,7 +1678,8 @@ cleanup:
>>      vshSnapshotListFree(snaplist);
>>      VIR_FREE(parent_snap);
>>      VIR_FREE(state);
>> -    virDomainSnapshotFree(start);
>> +    if (start)
>> +        virDomainSnapshotFree(start);
>>     
>
> ACK.
>   

Thanks, pushed now.

Regards,
Jim