Re: [Qemu-devel] [PATCH v2 0/3] HMP/snapshot changes - do not use ID anymore

[Eric Blake]

On 1/10/19 11:06 AM, Dr. David Alan Gilbert wrote:

>>> savevm [-t] [-i] [tag|id]
>>>
>>> then:
>>>   a) with neither -t or -i  it would behave in the same roulette way
>>>      as it does in the moment, and it might be a tag or id
>>>
>>>   b) with -t we'd explicitly treat the parameter as a tag and it
>>>      would error if it wasn't found
>>>
>>>   c) With -i we'd explicitly treat the parameter as an id and
>>>      it would error if it wasn't found
>>>
>>> Since we still allow (a) it doesn't break any existing code.
>>
>> If you can explain why we need both tag and id?
>>
>> And by keeping the current behaviour, we might not break hypothetically
>> existing correct code, but we leave currently actually existing broken
>> code like libvirt broken.
> 
> My only reason for leaving both tag & id was for the hypothetical
> existing current code; my assumption adding the above would be that we
> would then fix libvirt never to use (a),  probably always (b).

How? HMP is not introspectible, so libvirt can't know if 'savevm -t'
works without trying it.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

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