What kind of platforms would you be worried about missing out on. Rust platform support[1] looks pretty solid, but of course isn't that of, say, C, but in practice I am not aware of (but would love to learn about!) Use cases for running a vcs on more obscure platforms.

[1] https://forge.rust-lang.org/platform-support.html

"I don't recognize your platform.

Rust runs on Windows, Linux, Mac OS X, FreeBSD and NetBSD. If you are on one of these platforms and are seeing this then please report an issue, along with the following values:

  navigator.platform:
    SunOS i86pc
  navigator.appVersion:
    5.0 (X11)

To install Rust, if you are running Unix, run the following in your terminal, then follow the onscreen instructions.

  curl https://sh.rustup.rs -sSf | sh"

...and running that gives:

  curl: (35) error:14077410:SSL routines:SSL23_GET_SERVER_HELLO:sslv3 alert handshake failure

And I am running UNIX, a true, AT&T System V, Release 4.0 UNIX: Solaris 10 on i86pc.

I don't want to have to give up Mercurial just because someone somewhere is trying to be trendy by rewriting parts of it in Rust, because he thinks that's all the rage now.

That's a curl error to do with ssl versions, try using something other than curl to download it.

Actually, after a bit more research it looks like Solaris is a lower tier platform, which means there are no prebuilt binaries that are available, but it should work if you build it yourself.

I've been using Mercurial on Solaris 10 since 2006.

What you're saying is that if I had to upgrade to a newer version of Mercurial which used software written in Rust, I'd have to bootstrap and port an entire programming language, just to use a newer version of my revision control software?

That would be entirely up to the maintainers of Mercurial if they would distribute pre-built packages for Solaris 10. If you're concerned, you'd be better off making the case to them to do just that.

It's about the concept, not about Mercurial per se: nobody should be forced to have to bootstrap and port an entire programming language just to be able to use a newer version of an application. That's insane and irresponsible, not to mention selfish.

How strongly are you claiming "nobody" here? Does the cost of supporting niche platforms ever get too high in your mind? If so, what is an appropriate line to draw for cutting off explicit support?

Hopefully, it would increase pressure to actually port it there or to use another compiler like mrustc[0]

[0] https://github.com/thepowersgang/mrustc