Re: [libvirt] [PATCH 1/2] virsh: list required options first

On 04/15/2011 02:33 PM, Eric Blake wrote: Pushed with the following commit message: commit 6b75a1a5b0d10b42e3fd344b2067a176ee294f46 Author: Eric Blake <eblake(a)redhat.com&gt; Date: Tue Apr 12 14:58:02 2011 -0600 virsh: list required options first The current state of virsh parsing is that: $ virsh vol-info /path/to/image $ virsh vol-info --pool default /path/to/image $ virsh vol-info --pool default --vol /path/to/image all lookup the volume by path (technically, the last two also attempt a name lookup within a pool, whereas the first skips that step, but the end result is the same); meanwhile: $ virsh vol-info default /path/to/image complains about unexpected data. Why? Because the --pool option is optional, so default was parsed as the --vol argument, and /path/to/image.img doesn't match up with any remaining options that require an argument. For proof, note that: $ virsh vol-info default --vol /path/to/image complains about looking up 'default' - the parser mis-associated both arguments with --vol. Given the above, the only way to specify pool is with an explicit "--pool" argument (you can't specify it positionally). However, named arguments can appear in any order, so: $ virsh vol-info /path/to/image --pool default $ virsh vol-info --vol /path/to/image --pool default have also always worked. Therefore, this patch has no functional change on vol-info option parsing, but only on 'virsh help vol-info' synopsis layout. However, it also allows the next patch to 1) enforce that required options are always first (without this patch, the next patch would fail the testsuite), and 2) allow the user to omit the "--pool" argument. That is, the next patch makes it possible to do: $ virsh vol-info /path/to/image default which to date was not possible. * tools/virsh.c (opts_vol_create_from, opts_vol_clone) (opts_vol_upload, opts_vol_download, opts_vol_delete) (opts_vol_wipe, opts_vol_info, opts_vol_dumpxml, opts_vol_key) (opts_vol_path): List optional pool parameter after required arguments. -- Eric Blake eblake(a)redhat.com +1-801-349-2682 Libvirt virtualization library http://libvirt.org