Intro

I recently switched from fedora 41 to arch linux and found formatting in C# with my current configuration not working properly anymore

More precisely:

1. Formatting with omnisharp doesn't apply .editorconfig although properly configured +

2. When setting up csharpier as formatter for .cs files, Conform can't execute dotnet-csharpier anymore (as opposed to my fedora setup) due to :ConformInfo reporting No frameworks were found

If you encounter similar issues on whatever system you're on, this article might just be what you need.

Scenario

Let's say we use the omnisharp LSP for formatting our .cs files and we have an .editorconfig in our project path:

.
├── bin
├── .editorconfig
├── MyConsole.csproj
├── obj
└── Program.cs

The .editorconfig in our project path to define formatting rules looks like this:

root = true

# All files
[*]
charset = utf-8-bom
max_line_length = 20

# ...

The trained eye immediately spots the ridiculous max_line_length value of 20.

Given we have a ~/.omnisharp/omnisharp.json file configured, as mentioned above, to make omnisharp use the project's .editorconfig for it's formatting, ..

// ~/.omnisharp/omnisharp.json
// ...
  "FormattingOptions": {
    "enableEditorConfigSupport": true
  }
// ...

.. I would now expect any formatted file to look ridiculous:

Console.WriteLine(
    "Hello, World!"
);
Console.WriteLine(
    "Hello, World!"
);
Console.WriteLine(
    "Hello, World!"
);
Console.WriteLine(
    "Hello, World!"
);
Console.WriteLine(
    "Hello, World!"
);
Console.WriteLine(
    "Hello, World!"
);

The Problem

Interestingly max_line_length does not seem to be regarded by omnisharp - whether that is a bug or a feature, I don't know. Either way, when I use <leader>fm inside neovim nothing happens.

Running dotnet format in the terminal magically also doesn't do the expected formatting either.

The Solution: Preparation

Arch Linux based docker test container

In order to reproduce the arch-linux specifc scenario, we create the following Dockerfile

FROM archlinux:latest

# Install required packages
RUN pacman -Sy --noconfirm \
    ansible-core ansible \
    sudo \
    curl \
    gcc \
    git \
    neovim \
    ripgrep \
    unzip \
    npm \
    wget \
    dotnet-sdk-8.0 && \
    ansible-config init --disabled > /ansible.cfg && \
    pacman -Scc --noconfirm

# Create a new user 'ramboe' and give sudo access
RUN useradd -m -s /bin/bash ramboe && \
    echo "ramboe ALL=(ALL) NOPASSWD:ALL" >> /etc/sudoers

# Switch to the new user and set up home
USER ramboe
WORKDIR /home/ramboe

RUN mkdir Downloads Documents

RUN cd Documents
RUN dotnet new console -n MyConsole


CMD ["/bin/bash"]

then we build it with

docker build -t arch-dotnet-ramboe .

And finally run the container with

docker run -it --name my-arch-dotnet-container arch-dotnet-ramboe

you can start a exited container with

docker start -i my-arch-dotnet-container

[Docker Container] Ramboe nvim configuration

https://git.ramboe.io/configuration/dotfiles contains is the exact C# neovim configuration that ist already shown here

To install it, simply follow the instructions in the README.md

[Docker Container] Omnisharp Configuration

In case it doesn't already exist, create a omnisharp.json file inside the ~/.omnisharp directory like so

touch ~/.omnisharp/omnisharp.json

and make sure it configures omnisharp to enable .editorconfig support:

// ~/.omnisharp/omnisharp.json

{
  "RoslynExtensionsOptions": {
    "enableAnalyzersSupport": false
  },
  "FormattingOptions": {
    "enableEditorConfigSupport": true
  }
}

The Solution

Options to solve the problem

In essence we have two options to choose from

1. Use a different LSP instead of omnisharp that (hopefully) applies .editorconfig properly
2. Use csharpier for formatting - with csharpier the .editorconfig is applied properly as well.

We go for option 2, csharpier, since we cannot only use it locally during development but also in a CI/CD pipeline and still expect consistent results.

In order to use csharpier with neovim, we use a plugin called Conform.

Conform - A Brief Introduction

NvChad makes it easy for us to deal with formatting since it ships already with conform pre-installed and pre-configured.

Within the default nvchad installation, we find a file ~/.config/nvim/lua/configs/conform.lua that contains the formatting configuration for each file type:

-- ~/.config/nvim/lua/configs/conform.lua

local opts = {
  formatters_by_ft = {
    cs = { "csharpier" }, -- go into the 'formatters' section below and use whatever executable you find defined in the  'csharpier' block to format .cs files
  -- ...
  },
  formatters = {
   -- ...
    csharpier = {
      command = "dotnet-csharpier",
      args = { "--write-stdout" },
    },
  },
}

require("conform").setup(opts)

formatters_by_ft means "formatters by file type"

Essentially conform is a wrapper that automatically assigns the correct formatting executable (prettier, xmlformat, ..) to whatever file type we have in the current buffer. Formatting is done by the executable, not by conform itself.

Setup Conform to use csharpier for .cs files

Make sure to have csharpier configured in your conform configuration, found in ~/.config/nvim/lua/configs/conform.lua:

[Arch Linux] The Problem with Csharpier

In order to do so conform needs to be able to load the executable correctly.

Mason Installation

Last time we installed csharpier with Mason

Which effectively installs the dotnet-csharpier executable on our system, in a way that neovim can use it. But does it?

But does it?

After the installation with Mason, although available for neovim, we are still not able to do a dotnet-csharpier in the terminal, at least on arch:

Which might be fixable if we add csharpier to the ENV variable which still not guarantees that it is going to work properly when hitting <leader>fm.

Conform is not amused

Although we installed the latest version of dotnet 8 with

sudo pacman -S dotnet-sdk-8.0

and are able to build, debug and run dotnet 8 applications, csharpier, as defined in '' is unhappy because :ConformInfo says No frameworks were found:

This is because the version of csharpier that is installed with Mason needs the specific version 8.0.100, which we have to install separately next to the latest version that comes with sudo pacman -S dotnet-sdk-8.0

[Arch Linux] Making Conform Happy again

When we go to the arch linux dotnet documentation we find the script to install multiple versions side by side, along with the instructions on how to run it in the terminal:

We download the script and make it executable with

sudo chmod +x ./dotnet-install.sh

We also make slight adjustments to the terminal command, so we use the csharpier friendly version 8.0.100 and life time support:

sudo ./dotnet-install.sh --install-dir /usr/share/dotnet -channel LTS -version 8.0.100

make sure to run as sudo to avoid permisson errors

After that is done csharpier should work just fine the next time you open neovim and whatever .editorconfig shall be applied perfectly.