Nimlangserver won't format files with coc.nvim

[gmelodie]

nimlangserver times out when formatting file on save:

2025-04-10T11:27:01.887 INFO (pid:113263) [plugin] - coc.nvim initialized with node: v20.17.0 after �[33m146�[39m
2025-04-10T11:27:01.890 INFO (pid:113263) [services] - LanguageClient nim state change: stopped => starting
2025-04-10T11:27:01.896 INFO (pid:113263) [language-client-index] - Language server "languageserver.nim" started with 113303
2025-04-10T11:27:02.238 INFO (pid:113263) [services] - LanguageClient nim state change: starting => running
2025-04-10T11:27:02.244 INFO (pid:113263) [services] - service languageserver.nim started
2025-04-10T11:27:13.965 WARN (pid:113263) [handler-format] - Attempt to format file:///~/repos/nim-libp2p/libp2p/protocols/rendezvous.nim on save timed out after 500ms
2025-04-10T11:27:19.197 INFO (pid:113263) [attach] - Request action: fillDiagnostics [ �[33m1�[39m ]
2025-04-10T11:27:31.325 INFO (pid:113263) [attach] - receive notification: openLog []

Here's my coc-settings.json file for reference:

{
    "rust-analyzer.serverPath": "~/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/rust-analyzer",
    "rust-analyzer.checkOnSave.overrideCommand": [
        "./cargo",
        "xcheck",
        "--json-output"
    ],
    "notification.disabledProgressSources": [
        "*"
    ],
    "languageserver": {
        "nim": {
            "command": "nimlangserver",
            "filetypes": [
                "nim"
            ],
            "trace.server": "verbose",
            "settings": {
                "nim": {
                    "nimsuggestPath": "~/.nimble/bin/nimsuggest"
                }
            }
        }
    },
    "coc.preferences.messageLevel": "debug",
    "coc.preferences.formatOnSave": true
}

Obs: I'm using the newest nimlangserver version installed both with nimble install nimlangserver and building from source (both give the same error)

Has anyone run into similar issues and knows what could be? Perhaps I'm missing a coc config?

[gmelodie]

Btw I'm using this workaround for the time being which seems to be doing the trick, but still having a 500ms timeout for nothing is annoying, so I reduced the timeout to the minimum of 200ms in coc-settings.json: "coc.preferences.formatOnSaveTimeout": 200

" Auto-format Nim files with nph before saving
augroup nimfmt
    autocmd!
    autocmd BufWritePre *.nim silent! execute '!nph ' . shellescape(expand('%')) | edit!
augroup END

[jmgomez]

it may be an nph issue. Can you format that same file with the nph cli?

[gmelodie]

Yup running raw nph works fine, so does using neoformat. My previous workaround had bugs I did not properly understand (I think it has to do with the order in which nph is run, making it overwrite my changes when I detects a compilation error). I moved to use neoformat, but would be nice to not have to use neoformat only for Nim.

Here's the config I put in my init.vim for auto formatting with neoformat upon save (only for .nim files):

augroup fmt
  autocmd!
  autocmd BufWritePre *.nim undojoin | Neoformat
augroup END