BALATON Zoltan <bala...@eik.bme.hu> writes: > On Thu, 6 Feb 2025, Akihiko Odaki wrote: >> On 2025/02/06 18:48, Markus Armbruster wrote: >>>> This problem can be solved >>>> using an existing mechanism, OnOffAuto, which differentiates the "auto" >>>> state and explicit the "on" state. >>> >>> I guess you're proposing something like this: >>> >>> * auto: on if possible, else off >>> >>> * on: on if possible, else error >>> >>> * off: off (always possible) >>> >>> Which one is the default? >> >> I converted on to auto and off to false in a following patch. >> >>>> However, converting bool to OnOffAuto surfaces another problem: they >>>> disagree how "on" and "off" should be written. Please note that the >>>> disagreement already exists and so it is nice to solve anyway. >>> >>> Yes, converting bool to OnOffAuto is an incompatible change. >> >> Not just about conversion, but this inconsistency require users to know >> whether a property is bool or OnOffAuto and change how the values are >> written in JSON accordingly. This somewhat hurts usability. > > Worse than that, the help text is also confusing. > Excerpt from -device virtio-gpu,help > > blob=<bool> - on/off (default: false) > busnr=<busnr> > disable-legacy=<OnOffAuto> - on/off/auto (default: "auto") > disable-modern=<bool> - (default: false) > edid=<bool> - on/off (default: true) > event_idx=<bool> - on/off (default: true) > > For bools it says on/off yet expects true/false. Wasn't originally true/on/1 > and false/off/0 accepted for bools? Where that got lost? I think getting back > that behaviour would be easiest for users. Users don't care if OnOffAuto is > an enum internally and can't (or don't want to) remember if bools are written > on/off or true/false so accepting these as synonyms would help users.
The help text printed by -device is about usage of -device, not about QMP. There, the preferred syntax for bool values is on/off, but yes/true/y/no/false/n are also accepted. I think that's a disgusting mess, but it's here to stay, so let's not argue this any further. Instead of "(default: true)" we should have "(default: on)". All of this is a digression from the topic at hand, which is QMP.
