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

[Eric Blake]

On 1/9/19 10:57 AM, Daniel Henrique Barboza wrote:

>> I think we had a short discussion about just disallowing numeric
>> snapshot names.  How bad would that be?
> 
> 
> This was my first idea when evaluating what to do in this case. I gave
> it up because
> I found it to be too extreme. People would start complaining "I was able
> to do
> savevm 0 and now I can't".

I could live with that, especially if it serves to prevent even more
bugs of "I did this and now my image is broken" (I, for one, have known
about the confusion of breaking an image by using a number as a snapshot
name as far back as 2011). What I can't live with is:

"I have an old image where I did savevm 0, and now want to modernize the
image, but the new tools refuse to even let me read from name 0".

I also agree that the code is already so hairy, and the reason we have
punted on solving the issue (for 8 years now!) is because there are so
many corner cases to consider.  It also means that I'm reluctant to
review the patch, because it will require a significant chunk of time
and mental effort to ensure that whatever patch is proposed does not
break something important.  But in general, I'm glad that you are trying
to get the issue fixed, even if the conversation on HOW to fix it is
still undergoing a choice of bikeshed paint colors.

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

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