Re: git: 8bae22bbbe65 - main - fusefs: prefer new/delete over malloc/free

On Fri, Jan 19, 2024 at 11:24 AM Enji Cooper <yaneurabeya@gmail.com> wrote:

>
> > On Jan 19, 2024, at 10:15, John Baldwin <jhb@freebsd.org> wrote:
> >
> > On 1/19/24 7:38 AM, Alan Somers wrote:
> >>> On Fri, Jan 19, 2024 at 6:56 AM Alan Somers <asomers@freebsd.org>
> wrote:
> >>>
> >>> On Thu, Jan 18, 2024 at 10:32 PM Enji Cooper <yaneurabeya@gmail.com>
> wrote:
> >>>>
> >>>>
> >>>>> On Jan 17, 2024, at 2:50 PM, Alan Somers <asomers@FreeBSD.org>
> wrote:
> >>>>>
> >>>>> The branch main has been updated by asomers:
> >>>>>
> >>>>> URL:
> https://cgit.FreeBSD.org/src/commit/?id=8bae22bbbe6571da9259e0d43ffa8a56f4b3e171
> >>>>>
> >>>>> commit 8bae22bbbe6571da9259e0d43ffa8a56f4b3e171
> >>>>> Author:     Alan Somers <asomers@FreeBSD.org>
> >>>>> AuthorDate: 2024-01-15 23:49:47 +0000
> >>>>> Commit:     Alan Somers <asomers@FreeBSD.org>
> >>>>> CommitDate: 2024-01-17 22:49:41 +0000
> >>>>>
> >>>>>    fusefs: prefer new/delete over malloc/free
> >>>>>
> >>>>>    MFC after:      2 weeks
> >>>>>    Reviewed by:    kib
> >>>>>    Differential Revision: https://reviews.freebsd.org/D43464
> >>>>
> >>>> Why not use smart pointers instead?
> >>>> -Enji
> >>>
> >>> Only because this stuff all evolved from C code.  Smart pointers would
> >>> certainly work.
> >> Actually, TBH it's because I'm not real great with C++.  It's a
> >> difficult language, and after 2016 I stopped even trying to improve my
> >> C++ skills.  Instead, I've been focusing on Rust.  Even when I wrote
> >> these tests in 2019, I strongly considered using Rust instead of C++.
> >> In the end, the only thing that forced me to use C++ is because I
> >> wanted them to live in the base system, rather than in ports.
> >> I still dream about the day when Rust is allowed in the base system.
> >> If it were, then in addition to these tests, I would've converted
> >> gstat to Rust (rather than add sysutils/gstat-rs to ports), added the
> >> nfs-exporter (instead of putting it in net-mgmt/nfs-exporter), added a
> >> ctl-exporter (which is impossible to do in ports, so I had to do that
> >> one in C), and converted tools/regression/fsx in place (instead of
> >> putting in devel/fsx-rs).  Maybe a couple of other things, too.  Like
> >> ztop, or the geom-exporter that I have half-written.  I've also been
> >> tempted to rewrite zfsd in Rust.
> >> Alas, I sense that there is little appetite for bringing Rust into
> contrib.
> >
> > Brooks' opinion is that to support Rust in base we probably need to
> require
> > always using an external toolchain as otherwise we would need to keep two
> > copies of LLVM in base.
>
> Based on my recent adventures with this, I concur. Our version of LLVM in
> base is not compatible with the copy rust needs, so rust would always need
> to be bootstrapped with world.
>
> It would need to be a full toolchain as well to build all of the rust
> targets. Using llvm built for a single target would only function as the
> initial bootstrap toolchain.
>
> Finally, the bootstrap compiler (via rustup) has tight requirements around
> versioning and is precompiled for the host. It turns into a nightmare if
> new syscall support is added or if compat support is required to run the
> binary…
>
> We’d be better off importing golang instead of rust.
>

I have no problems supporting rust via an external toolchain, but I'd also
view that support
to be provisional: Show us what can be done better and the niggling issues
that one hits
around toolchain stuff somehow is paid for with something that's way cooler
than we could
otherwise have. Tests seem like a natural first step in that. I mean, if we
can't even support
tests without it being a hassle, then it's a complete no-go. If we can,
then what else can we
support? For more ambitious things, there's always ports and the base /
ports distinction is
likely to fade somewhat as pkgbase becomes more mature.

Warner