[nightly] transform `--nocapture` arg when using nextest

[giggio]

Have you read the docs and searched existing issues?

• I have read the README's troubleshooting guide and FAQ(https://github.com/mrcjkb/rustaceanvim?tab=readme-ov-file#left_speech_bubble-faq).
• I am using the latest rustaceanvim release.
• I have searched existing issues.
• I have searched existing discussions.
• I have searched the existing issues of other plugins related to this issue (if applicable).
• I have searched the existing rust-analyzer issues (if applicable).
• I can reproduce the issue with stable Neovim (not a distribution or nightly) and the minimal config. Do not open issues here if you are using a distro (like LazyVim) to reproduce.
• This is an issue about rustaceanvim, not rust-analyzer or Neovim.
• I am not using mason.nvim to manage my rust-analyzer installation.
• This is not an issue with (auto)completion.

Neovim version (nvim -v)

0.11.4

Operating system/version

Ubuntu 24.04.3

Output of :checkhealth rustaceanvim

rustaceanvim:                                                               ✅

Checking for Lua dependencies ~
- ✅ OK [mfussenegger/nvim-dap](https://github.com/mfussenegger/nvim-dap) installed.

Checking external dependencies ~
- ✅ OK rust-analyzer: found rust-analyzer 1.92.0-nightly (695857b 2025-10-21)
- ✅ OK Cargo: found cargo 1.92.0-nightly (367fd9f21 2025-10-15)
- ✅ OK rustc: found rustc 1.92.0-nightly (695857bc3 2025-10-21)
- ✅ OK cargo-nextest: found cargo-nextest 0.9.106
- ✅ OK debug adapter: found codelldb 

Checking config ~
- ✅ OK No errors found in config.

Checking for conflicting plugins ~
- ✅ OK No conflicting plugins detected.

Checking for tree-sitter parser ~
- ✅ OK tree-sitter parser for Rust detected.

How to reproduce the issue

git clone https://github.com/giggio/rustacean_bug1.git
cd rustacean_bug1
nvim -u minimal.lua
# in nvim:
:e proj1/src/main.rs
:RustLsp testables
# see error

Expected behaviour

Tests run

Actual behaviour

error: failed to parse test binary arguments --nocapture: arguments are unsupported

[Process exited 96]

The minimal config used to reproduce this issue.

vim.env.LAZY_STDPATH = '.repro'
load(vim.fn.system('curl -s https://raw.githubusercontent.com/folke/lazy.nvim/main/bootstrap.lua'))()

require('lazy.minit').repro {
  spec = {
    {
      'mrcjkb/rustaceanvim',
      version = '^6',
      init = function()
        vim.g.rustaceanvim = {        }
      end,
      lazy = false,
    },
  },
}

Additional context:

I provided a shell.nix and flake.nix in the repo.
If not in a workspace, it works.
If not using nextest, it works (if you comment out enable_nextest = false in minimal.lua).
If using neotest with rustaceanvim, it fails with "Failed to read junit.xml file", which is the error I found first.

[mrcjkb]

Hey 👋

I cannot reproduce this with the devShell and the steps you provided.
My :checkhealth rustaceanvim outputs different commit SHAs in the rust toolchain dependencies:

Checking external dependencies ~
- ✅ OK rust-analyzer: found rust-analyzer 1.92.0-nightly (6501e64 2025-10-23)
- ✅ OK Cargo: found cargo 1.92.0-nightly (344c4567c 2025-10-21)
- ✅ OK rustc: found rustc 1.92.0-nightly (6501e64fc 2025-10-23)
- ✅ OK cargo-nextest: found cargo-nextest 0.9.106

This is likely an issue that's caused by a nightly version, so I'll close this.
If it is reproducible with an up-to-date non-nightly toolchain, please reopen.

[giggio]

Thanks for the answer, @mrcjkb. You were right, something wrong with nightly.

I got the testables:

Runnables                                                                                                                                                                                       
1: tests                                                                                                                                                                                        
2: tests::test_add                                                                                                                                                                              
3: proj1 (all targets)

I've updated the repo with the latest flake.lock file in a new commit, to make it clear.

I ran into another issue in nightly, I'll write it down bellow, it does not happen with stable, feel free to ignore it:

Now I'm getting a weird error if I select option 1 or 2 (don't run all targets):

error: failed to parse test binary arguments `--nocapture`: arguments are unsupported                                                                                                           
                                                                                                                                                                                                
[Process exited 96]

The command shown in the status bar was:

term://~/rustbug//3008471:cd '~/rustbug' && cargo nextest run --package proj1 --bin proj1 --profile rustaceanvim --config-file ~/rustbug/
.repro/cache/nvim/rustaceanvim/nextest_1.toml -- tests --nocapture 

I have no idea where --nocapture came from. I searched this repo for it, and found it nowhere. I don't have anything in an env variable that could influence it.

Disabling nextest makes it work (or using stable). If you'd like I can open another issue.

Anyway, thanks for the help.

[mrcjkb]

Hmm, it appears nightly is passing --nocapture to the generated test executable.
Cargo-nextest doesn't generate a --nocapture arg, but instead expects it to be passed to cargo-nextest.

I.e., where cargo expects:

cargo test -- tests --nocapture 

Cargo-nextest expects:

cargo nextest run --nocapture -- tests