Re: [Qemu-devel] [PATCH 1/7] qemu-img create: Detect options specified more than once

[Eric Blake <eblake@redhat.com>]

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On 02/19/2014 08:12 AM, Kevin Wolf wrote:
> If you specified multiple -o options for qemu-img create, it would
> silently ignore all but the last one. Similarly, for other options the
> last occurence wins (which is at least a bit less surprising). Error out

s/occurence/occurrence/

> instead.

For other options, erroring out is okay.  But for -o, I would prefer if
we could concatenate multiple -o as if they had been passed in one
larger -o, rather than erroring out.  That is, I'd rather treat:

-o backing_file=/path/to/foo -o backing_fmt=qcow2

as a synonym of

-o backing_file=/path/to/foo,backing_fmt=qcow2

> 
> The only exception is a -o help option, which may be added to any valid
> qemu-img create command and ignores all other options.

If you consider my above request for concatenating multiple -o options,
rather than rejecting duplicates, then that means:

-o backing_file=/path/to/foo,help

would have to do the right thing about displaying help.

I also have the complaint that:

qemu-img create -o help -f qcow2

does not tell me the qcow2 specific options; I have to do something like:

qemu-img create -o help -f qcow2 /dev/null

It would be nice if we could make -o help smarter so that it no longer
requires the presence of a file name (probably a separate patch).

In other words, I like that your series is trying to improve things, but
I don't think it is making the right improvement.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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