On 07/06/2016 14:54, Igor Mammedov wrote: > On Tue, 7 Jun 2016 14:36:51 +0200 > Paolo Bonzini <pbonz...@redhat.com> wrote: > >> On 07/06/2016 14:32, Igor Mammedov wrote: >>>>> Could you detect using +foo together with foo=off, and -foo together >>>>> with foo=on? Those are the really problematic cases, without them +foo >>>>> and -foo can become synonyms for =on and =off. >>> That's (legacy)current semantic of -cpu +-foo where it overrides any foo=x, >>> potentially it's possible to track foo=x locally in parser >>> and then compare with +-foo both ways. >>> But all we can do currently is to print warning about such use case. >>> >>> I think Eduardo's suggestion to just warn that +-foo is obsolete for now >>> and drop support for it in several releases is sufficient(good) enough. >> >> kvm-unit-tests and libvirt both use it, especially because =on and =off >> are relatively new I think? It seems like it's really widespread. > > Yep, that's why it's not removed now. > Looks like libvirt would be able to switch to foo=x syntax, > I can take a look at kvm-unit-tests and make it use foo=x too.
And all tutorials, and all scripts. It's really too hard. I'd really prefer to make an incompatible change straight in 2.7 for the case of mixed foo=x and [+-]foo. Paolo
