What is preventing Microsoft from pulling an Oracle and suing Valve, CodeWeavers, or individual Wine maintainers for re-implementing Win32?

This question has been nagging at me for a while. Regardless of how much validity there is to the lawsuit, I imagine that going to trial would be supremely risky, because if you happen across anybody working on Wine that saw something they weren't supposed to, you could sink the whole project.

I cannot imagine Microsoft sitting by and quietly letting their Windows monopoly vanish between their fingers. Selling Windows may not be their primary focus these days, but why give up an advantage like that?

First, they probably wouldn't win. Oracle lost Google v Oracle. Wine is pretty serious about clean-room principles -- they won't accept a patch from anyone who's ever so much as looked at Microsoft-owned source code.[1] Valve has the means and motive to fight a lawsuit to the bitter end.

Second, it would be a PR disaster. "Microsoft sues to kill the Steam Deck" is an awful look for the company. Their strategy in recent years has been to say "actually we like Linux now" and play friendly to try to win developers; this would run completely counter to that. There may not be much of an immediate consequence to this, but in the long run I think we'd see developers try to reduce their reliance on Microsoft/Windows.

Third, I don't think it would actually stop the tide. Wine and Proton are a big piece of the movement away from Windows, but they're not the only piece. The legal process would take many years to play out; during that time, we'd likely see tons of movement on making it easier for developers to create native Linux builds, and perhaps even new projects that try to find other ways to do Wine-like things without actually reimplementing Win32. Losing Wine would be a huge blow, but I don't think it'd be the end of the story.

[1]: https://gitlab.winehq.org/wine/wine/-/wikis/Submitting-Patch...

Oracle lost Google v. Oracle.

The main issues I'm aware of are whether APIs are copyrightable, and if so, whether implementing them qualifies as fair use.

https://en.wikipedia.org/wiki/Google_LLC_v._Oracle_America,_....

(And, of course, Microsoft would also have to consider whether such a lawsuit would have greater benefits than costs. I would like to think that customer goodwill has more than zero value, for example.)

I think there are two reasons this hasn't happened: (1) Wine might be useful to Microsoft at some point for providing backward compatibility in Windows itself; (2) it would be an extremely bad look/PR disaster to go after this project after spending so much time and money positioning yourself as an open source supporter

If anything Microsoft will give up their advantage by making Windows 11 a UX dumpster fire. If Windows 11 had an official way to turn off all of the garbage and opt out of their monopolistic PM-brained “features” a lot of us who switched to Linux probably wouldn’t have happened.

It will kill GitHub I suspect. Who will trust them if they can pull the plug on open source projects using the dumb "API is copyrightable" claim? I'd say last time they tried to pull that by backing Oracle in that legal case, they already damaged their reputation enough.

This stuff will never ever ever work real and reliably enough for Microsoft to care.

Normal people don't want to use Linux. Normal people can't even install an OS. None the less fight kernel regressions for days.

I can even imagine Microsoft coming out with MS Linux one day and contributing to Wine. That's far more likely at this point.