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

[Max Reitz]

On 06.09.18 13:11, Daniel Henrique Barboza wrote:
> changes in v2:
> - removed the "RFC" marker;
> - added a new patch (patch 2) that removes
> bdrv_snapshot_delete_by_id_or_name from the code;
> - made changes in patch 1 as suggested by Murilo;
> - previous patch set link:
> https://lists.gnu.org/archive/html/qemu-devel/2018-08/msg04658.html
> 
> 
> It is not uncommon to see bugs being opened by testers that attempt to
> create VM snapshots using HMP. It turns out that "0" and "1" are quite
> common snapshot names and they trigger a lot of bugs. I gave an example
> in the commit message of patch 1, but to sum up here: QEMU treats the
> input of savevm/loadvm/delvm sometimes as 'ID', sometimes as 'name'. It
> is documented as such, but this can lead to strange situations.
> 
> Given that it is strange for an API to consider a parameter to be 2 fields
> at the same time, and inadvently treating them as one or the other, and
> that removing the ID field is too drastic, my idea here is to keep the
> ID field for internal control, but do not let the user set it.
> 
> I guess there's room for discussion about considering this change an API
> change or not. It doesn't affect users of HMP and it doesn't affect Libvirt,
> but simplifying the meaning of the parameters of savevm/loadvm/delvm.

(Yes, very late reply, I'm sorry...)

I do think it affects users of HMP, because right now you can delete
snapshots with their ID, and after this series you cannot.

I think we had a short discussion about just disallowing numeric
snapshot names.  How bad would that be?

Max

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