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Date:   Mon, 24 Aug 2020 00:02:46 +0300
From:   Adrian Bunk <bunk@kernel.org>
To:     Josh Triplett <josh@joshtriplett.org>
Cc:     Nick Desaulniers <ndesaulniers@google.com>, alex.gaynor@gmail.com,
        geofft@ldpreload.com, jbaublitz@redhat.com,
        Masahiro Yamada <masahiroy@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Greg KH <gregkh@linuxfoundation.org>,
        Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        LKML <linux-kernel@vger.kernel.org>,
        clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: Linux kernel in-tree Rust support
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On Sun, Jul 12, 2020 at 12:39:44PM -0700, Josh Triplett wrote:
>...
> Rust has hard stability guarantees when upgrading from one stable
> version to the next. If code compiles with a given stable version of
> Rust, it'll compile with a newer stable version of Rust.
>...

In librsvg, breakages with more recent Rust versions in the past year
required updates of two vendored crates:
https://gitlab.gnome.org/GNOME/librsvg/-/commit/de26c4d8b192ed0224e6d38f54e429838608b902
https://gitlab.gnome.org/GNOME/librsvg/-/commit/696e4a6be2aeb00ea27945f94da066757431684d

For updating Rust in Debian stable for the next Firefox ESR update it 
would actually be useful if these violations of the "hard stability 
guarantee" in Rust get fixed, so that the old librsvg 2.44.10 builds 
again with the latest Rust.

It also makes me wonder how such regressions slip into Rust releases.

cu
Adrian