Cargo "subslice patterns are unstable" Causes Build To Fail

[jlpoolen]

I upgraded my Raspberry Pi4. Then "git pull" the work area I had compiled this project in around June 2020.

 pi@raspberrypi:/usr/local/src/moonfire-nvr/server $ uname -a
 Linux raspberrypi 5.10.11-v7l+ #1399 SMP Thu Jan 28 12:09:48 GMT 2021 armv7l GNU/Linux
 pi@raspberrypi:/usr/local/src/moonfire-nvr/server $ cargo --version
 cargo 1.42.1

The build failed citing:

  error[E0658]: subslice patterns are unstable

Last error repeats 10 previous ones for different parts of the code:

 error[E0658]: subslice patterns are unstable
    --> /home/pi/.cargo/registry/src/github.com-1ecc6299db9ec823/object-0.23.0/src/read/mod.rs:196:28
     |
 196 |             | [0x64, 0x86, ..] => FileKind::Coff,
     |                            ^^
     |
     = note: for more information, see https://github.com/rust-lang/rust/issues/62254

Log (6 month expiration) at: https://pastebin.com/Qy0UeR2D

Background My SD card was corrupted, but multiple attempts to boot somehow caused it to fix itself... I may have had interfence from my hard disk array and possibly Raspberry Pi was trying to boot from a disk thereon, I ended up turning off all the disks and then tried booting Raspberry Pi where I found initialization message waiting to find the hard disk array; I then turned on the array and the boot completed. I then upgraded my system "apt upgrade", took 40 minutes. Found cargo gone, i guess upgrades in Raspberry Land mean previously installation of packages get jettisoned. Installed current available version of cargo and then attempted to build.

[scottlamb]

I bump the minimum Rust version from time to time. It's at 1.45 now, so it's unsurprising you can't build with 1.42 anymore. rustup update should solve the problem.

[jlpoolen]

For the record:

on a rebuilt RaspberryPi4 as of today, I used the apt-cache to install rustc and it installed 1.41:

jlpoole@pi:/usr/local/src/moonfire-nvr/server $ rustc -V
rustc 1.41.1
jlpoole@pi:/usr/local/src/moonfire-nvr/server $ cargo --version
cargo 1.42.1
root@pi:/usr/local/src/moonfire-nvr/server $ 

I found this closed Issue, of course, after I ran into compile problems. So, once again I ended up installing Rust directly from their web site:

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

[scottlamb]

Yeah, Rust is changing rapidly enough that it's hopeless to use the distribution packages in Debian-based distributions. (Maybe you can get away with it in Arch.)

[jlpoolen]

Let us not forget dear Gentoo which has 1.53 as the stable high watermark:

[I] dev-lang/rust-bin Available versions: (stable) 1.52.1 1.53.0 ~1.54.0 {clippy doc prefix rls rustfmt verify-sig ABI_MIPS="n32 n64 o32" ABI_S390="32 64" ABI_X86="32 64 x32" CPU_FLAGS_X86="sse2"} Installed versions: 1.53.0(stable)(01:16:04 AM 07/31/2021)(-clippy -doc -prefix -rls -rustfmt -verify-sig ABI_MIPS="-n32 -n64 -o32" ABI_S390="-32 -64" ABI_X86="64 -32 -x32" CPU_FLAGS_X86="sse2") Homepage: https://www.rust-lang.org/ Description: Systems programming language from Mozilla