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I installed Debian 11 before it was released officially. Its rustc was less than 3 months old. I personally ran into 2 rust programs I couldn't compile due to c

I installed Debian 11 before it was released officially. Its rustc was less than 3 months old. I personally ran into 2 rust programs I couldn't compile due to compiler forwards incompatibility within weeks. One example was the software defined radio program, plotsweep, if you want to look it up in cargo.

nicoburns 4y ago
That's an application, not a library though. There's really no reason for an application not to require the latest compiler version if they so choose. There are definitely libraries that take this approach too, but they tend to be higher-level domain-specific ones. The foundational libraries in the ecosystem tend to take a much more conservative approach to MSRV (minimum supported rust version), supporting older Rust versions for as long as possible, and only bumping the version when new features that significantly improve the library are released (and often only once the versions implementing those features are packaged in stable releases of major distros). For example, the `rand` crate supports Rust versions down to 1.36 (released in July 2019) [0], the regex crate supports down to 1.41.1 (released Feb 2020) [1], etc. [0]: https://github.com/rust-random/rand#rust-version-requirements https://github.com/rust-random/rand#rust-version-requirement... [1]: https://github.com/rust-lang/regex#minimum-rust-version-policy https://github.com/rust-lang/regex#minimum-rust-version-poli...
- superkuh 4y ago
  You're saying no true Scotsman will require the latest rust compiler. I'm saying that's not how it is for non-Rust developers trying to use things written in Rust.
  - nicoburns 4y ago
    I'm saying the really core libraries (the only ones the linux kernel would ever consider using) don't suffer from this problem. If your development environment is permissive enough that you can pick up a wider variety of libraries, then I can't see any reason not to use the latest compiler.
    - superkuh 4y ago
      So we agree. Programs written in Rust don't last more than a couple months. It's just the core libraries that are decent. Btw, I just attempted to install another rust program (legdur), and guess what, my rustc is too out of date to handle it ("failed to parse the `edition` key, this version of Cargo is older than the `2021` edition, and only supports `2015` and `2018` editions"). So that's 3 of 4 attempts to run Rust programs that have failed. Granted, my rustc is now about a year old, but that's still absurdly short.
      - zRedShift 4y ago
        > legdur First commit 2 months ago, started with edition 2021. https://hg.sr.ht/~cyplo/legdur/browse/Cargo.toml?rev=ca1181518277672e7f71bc3551efd1d3de1fc19c https://hg.sr.ht/~cyplo/legdur/browse/Cargo.toml?rev=ca11815... Have you tried compiling something less than bleeding edge, with a year old compiler, or are you picking projects specifically to "showcase" the supposed failings of the Rust compiler? Many libraries in the ecosystem have a MSRV (minimum support rust version) guarantee, with compile-time shims to enable newer features if a more recent version is detected. You can pin your dependencies to those versions (and if they don't have an explicit MSRV, just pin it to a version by date or by running https://github.com/foresterre/cargo-msrv https://github.com/foresterre/cargo-msrv on the project to find the effective MSRV). You can cargo install specific versions of a binary crate, and if they move to the 2021 edition, or use a recently stabilized standard library function or w/e, you can simply choose to install a specific version, that would work with your distro's rustc/cargo. I'm not even talking about the completely valid, but last resort strategy of many non-bleeding edge distro package maintainers, of simply creating a .patch file and applying it. In legdur's case, --- edition = "2021" +++ edition = "2018" on Cargo.toml would probably do the trick. For libraries/binaries you control, you can use https://doc.rust-lang.org/cargo/reference/overriding-dependencies.html https://doc.rust-lang.org/cargo/reference/overriding-depende... and https://github.com/itmettkeDE/cargo-patch https://github.com/itmettkeDE/cargo-patch. Giving up after the first minor roadblock and crying bloody murder is intellectually lazy.
      - nicoburns 4y ago
        > Programs written in Rust don't last more than a couple months. They last just fine much longer than that, you may just have to upgrade your compiler if you compile from source (doing so is a single command, takes about 30 seconds max, and new versions are backwards compatible so code targeting older compiler versions will still work). Importantly, you generally do not need the Rust compiler at all if you only wish to run Rust applications. You can usually download a pre-compiled binary distributed by the program authors. Applications (not libraries) requiring a recent compiler / language toolchain and updating as and when is convenient to them is hardly unique to Rust.

nicoburns 4y ago

That's an application, not a library though. There's really no reason for an application not to require the latest compiler version if they so choose. There are definitely libraries that take this approach too, but they tend to be higher-level domain-specific ones. The foundational libraries in the ecosystem tend to take a much more conservative approach to MSRV (minimum supported rust version), supporting older Rust versions for as long as possible, and only bumping the version when new features that significantly improve the library are released (and often only once the versions implementing those features are packaged in stable releases of major distros). For example, the `rand` crate supports Rust versions down to 1.36 (released in July 2019) [0], the regex crate supports down to 1.41.1 (released Feb 2020) [1], etc. [0]: https://github.com/rust-random/rand#rust-version-requirements https://github.com/rust-random/rand#rust-version-requirement... [1]: https://github.com/rust-lang/regex#minimum-rust-version-policy https://github.com/rust-lang/regex#minimum-rust-version-poli...

superkuh 4y ago
You're saying no true Scotsman will require the latest rust compiler. I'm saying that's not how it is for non-Rust developers trying to use things written in Rust.
- nicoburns 4y ago
  I'm saying the really core libraries (the only ones the linux kernel would ever consider using) don't suffer from this problem. If your development environment is permissive enough that you can pick up a wider variety of libraries, then I can't see any reason not to use the latest compiler.
  - superkuh 4y ago
    So we agree. Programs written in Rust don't last more than a couple months. It's just the core libraries that are decent. Btw, I just attempted to install another rust program (legdur), and guess what, my rustc is too out of date to handle it ("failed to parse the `edition` key, this version of Cargo is older than the `2021` edition, and only supports `2015` and `2018` editions"). So that's 3 of 4 attempts to run Rust programs that have failed. Granted, my rustc is now about a year old, but that's still absurdly short.
    - zRedShift 4y ago
      > legdur First commit 2 months ago, started with edition 2021. https://hg.sr.ht/~cyplo/legdur/browse/Cargo.toml?rev=ca1181518277672e7f71bc3551efd1d3de1fc19c https://hg.sr.ht/~cyplo/legdur/browse/Cargo.toml?rev=ca11815... Have you tried compiling something less than bleeding edge, with a year old compiler, or are you picking projects specifically to "showcase" the supposed failings of the Rust compiler? Many libraries in the ecosystem have a MSRV (minimum support rust version) guarantee, with compile-time shims to enable newer features if a more recent version is detected. You can pin your dependencies to those versions (and if they don't have an explicit MSRV, just pin it to a version by date or by running https://github.com/foresterre/cargo-msrv https://github.com/foresterre/cargo-msrv on the project to find the effective MSRV). You can cargo install specific versions of a binary crate, and if they move to the 2021 edition, or use a recently stabilized standard library function or w/e, you can simply choose to install a specific version, that would work with your distro's rustc/cargo. I'm not even talking about the completely valid, but last resort strategy of many non-bleeding edge distro package maintainers, of simply creating a .patch file and applying it. In legdur's case, --- edition = "2021" +++ edition = "2018" on Cargo.toml would probably do the trick. For libraries/binaries you control, you can use https://doc.rust-lang.org/cargo/reference/overriding-dependencies.html https://doc.rust-lang.org/cargo/reference/overriding-depende... and https://github.com/itmettkeDE/cargo-patch https://github.com/itmettkeDE/cargo-patch. Giving up after the first minor roadblock and crying bloody murder is intellectually lazy.
    - nicoburns 4y ago
      > Programs written in Rust don't last more than a couple months. They last just fine much longer than that, you may just have to upgrade your compiler if you compile from source (doing so is a single command, takes about 30 seconds max, and new versions are backwards compatible so code targeting older compiler versions will still work). Importantly, you generally do not need the Rust compiler at all if you only wish to run Rust applications. You can usually download a pre-compiled binary distributed by the program authors. Applications (not libraries) requiring a recent compiler / language toolchain and updating as and when is convenient to them is hardly unique to Rust.