Panic on weird n" in a Rust file

[mo8it]

Summary

I was writing the following line in Rust:

writeln!(writer, "{}\n", positions.len())?;

After entering \n, the editor crashed!

The panic is from the following line:

helix/helix-core/src/transaction.rs

Line 413 in d8f9b90

panic!("Positions {out_of_bounds:?} are out of range for changeset len {old_pos}!",)

Reproduction Steps

I found a minimal (and very weird) example to reproduce this bug:

1. Run the commands
   1. cargo new project
   2. cd project
   3. echo 'n"' > src/main.rs
   4. hx src/main.rs
2. Wait for the language server to start.
3. Press c over the character n to change it.
4. Helix crashes with the following error:

   thread 'main' panicked at 'Positions [(1, After), (1, After)] are out of range for changeset len 2!', /var/home/mo/code/compile/helix/helix-core/src/transaction.rs:413:9
   note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
   

Helix log

~/.cache/helix/helix.log

2023-06-27T16:20:03.976 helix_view::document [WARN] LSP formatting failed: protocol error: ServerError(-32900): rustfmt exited with:
                           Status: exit status: 101
                           stdout: 
                           stderr: error: prefix `n` is unknown
 --> <stdin>:1:1
  |
1 | n"
  | ^ unknown prefix
  |
  = note: prefixed identifiers and literals are reserved since Rust 2021
help: consider inserting whitespace here
  |
1 | n "
  |  +

error[E0765]: unterminated double quote string
 --> <stdin>:1:2
  |
1 | n"
  |  ^^

Platform

Linux

Terminal Emulator

Alacritty 0.12.1

Helix Version

helix 23.05 (d511122)

[mo8it]

@pascalkuthe @archseer This should be the buggy commit: d491e23

[mo8it]

Explicit panic in an editor does not sound like a good idea :/

[archseer]

Your helix version points to a commit from last month though? Can you try with the fix that has since landed in master 8d39a81

[mo8it]

Then hx --version is stuck on that commit. I did just make sure:

code/compile/helix on  master
❯ git pull -r && cargo +stable install --path helix-term
Already up to date.
  Installing helix-term v0.6.0 (/var/home/mo/code/compile/helix/helix-term)
    Updating crates.io index
    Finished release [optimized] target(s) in 2.57s
   Replacing /var/home/mo/.cargo/bin/hx
    Replaced package `helix-term v0.6.0 (/var/home/mo/code/compile/helix/helix-term)` with `helix-term v0.6.0 (/var/home/mo/code/compile/helix/helix-term)` (executable `hx`)
                                                                                                                                                                                                                   
code/compile/helix on  master took 3s
❯ hx --version
helix 23.05 (d5111222)
                                                                                                                                                                                                                   
code/compile/helix on  master
❯ git log -n 1
commit d8f9b901ddb1d91bf3ade66cf091e93b5cab6e49 (HEAD -> master, origin/master, origin/HEAD)
Author: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Date:   Tue Jun 27 15:37:22 2023 +0200
                                                                                                                                                                                                                   
    build(deps): bump libc from 0.2.146 to 0.2.147 (#7463)
                                                                                                                                                                                                                   
    Bumps [libc](https://github.com/rust-lang/libc) from 0.2.146 to 0.2.147.
    - [Release notes](https://github.com/rust-lang/libc/releases)
    - [Commits](https://github.com/rust-lang/libc/compare/0.2.146...0.2.147)
                                                                                                                                                                                                                   
    ---
    updated-dependencies:
    - dependency-name: libc
      dependency-type: direct:production
      update-type: version-update:semver-patch
    ...
                                                                                                                                                                                                                   
    Signed-off-by: dependabot[bot] <support@github.com>
    Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

❯ ls -l (which hx)
.rwxr-xr-x@ 26M USER 2023-06-27 16:32 /var/home/mo/.cargo/bin/hx

[pascalkuthe]

I can reproduce i will look into fix

[mo8it]

@pascalkuthe Thank you!

@archseer Should I open an issue about hx --version?