Re: [PULL 31/31] qemu-option: warn for short-form boolean options

[Peter Maydell]

On Tue, 16 Feb 2021 at 14:45, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> Il mar 16 feb 2021, 15:11 Peter Maydell <peter.maydell@linaro.org> ha scritto:
>>
>> On Tue, 16 Feb 2021 at 13:44, Paolo Bonzini <pbonzini@redhat.com> wrote:
>> >
>> > On 16/02/21 14:36, Peter Maydell wrote:
>> > > Broadly, I think that being able to say 'foo' when foo is a
>> > > boolean option being set to true is obvious and nice-to-use
>> > > syntax, and I don't really want it to go away. 'nofoo' for
>> > > 'foo=false' is much less obvious and I'm happy if we only
>> > > support it as a special-case for 'nowait'.
>> >
>> > It really depends on what the default  "-M pc,nographics" arguably makes
>> > sense too (more so than "-M pc,graphics" since true is the default).
>>
>> Is anybody using 'pc,nographics' ? google didn't find any examples.
>
>
> It's just an example that the prevalence of "nowait" over "wait" is simply 
> because the default of "server" is false while the default of "wait" is true. 
> Any boolean option whose default is true could benefit from a "no"-prefixed 
> short form. But I am pretty sure that there are users in the wild for noipv4 
> or noipv6.

I think 'nowait' is special only because for so long our documentation
has recommended 'server,nowait' (and possibly also because inetd
uses 'nowait'?). I don't think it's inherently much better than
"wait=off" or whatever. I just think that if we have a situation
where exactly 1 boolean option has very widespread use of 'nofoo' then
it's worth special casing it. If we had 50 boolean options which all
had about 10% use of 'nofoo' vs 90% 'foo=off' that would be different.

-- PMM