Re: [PATCH v6 04/14] block/amend: separate amend and create options for qemu-img

[Eric Blake]

On 5/14/20 7:28 AM, Max Reitz wrote:
> On 10.05.20 15:40, Maxim Levitsky wrote:
> > Some options are only useful for creation
> > (or hard to be amended, like cluster size for qcow2), while some other
> > options are only useful for amend, like upcoming keyslot management
> > options for luks

> >   
> > +#define QCOW_COMMON_OPTIONS                                         \
> > +    {                                                               \

> > +        .help = "Width of a reference count entry in bits",         \
> > +        .def_value_str = "16"                                       \
> > +    }                                                               \
>
> I think the last line should have a comma in it (otherwise the final
> backslash doesn’t make much sense, because whenever we’d add a new
> option, we would need to modify the line anyway to insert a comma).

Except that...

> Speaking of adding option, this requires a rebase due to the
> compression_type option added (not trivial in the strict sense, but
> still straightforward to handle).
>
> > +
> >   static QemuOptsList qcow2_create_opts = {
> >       .name = "qcow2-create-opts",
> >       .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head),
> >       .desc = {
>
> [...]
>
> > +        QCOW_COMMON_OPTIONS,
> > +        { /* end of list */ }

...the intended usage is to use the macro name followed by a comma, so 
including a trailing comma in the macro itself would lead to a syntax 
error.  I think the better fix is to eliminate the trailing \ on the 
final line, and have '}' without a trailing comma in the macro.

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