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 I think Eduardo's suggestion to just warn that +-foo is obsolete for now 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. Paolo