Feature Request: Support mix format plugins

[axelson]

Elixir 1.13 added mix format plugins: https://hexdocs.pm/mix/1.13.2/Mix.Tasks.Format.html#module-plugins

ElixirLS should support these plugins if defined in the user's project.

Initially requested in: elixir-lsp/vscode-elixir-ls#224

[megalithic]

Would this also enable support for elixir-ls to format, via LSP, *.html.heex files, too?

confirmed; a formatter plugin will allow for this.

[zachdaniel]

I may have time to make a PR to add support for this, what has to be done to make it work?

[msaraiva]

@zachdaniel -> elixir-lsp/vscode-elixir-ls#224 (reply in thread)

[megalithic]

Super pumped for this! Thanks y'all!

[anildigital]

Anyone know if it works for elixir-ls in Emacs?

[benvp]

With the recent addition of the LiveView formatter in 0.17.8 I noticed that the formatting does work automatically in VSCode when using .ex files with the ~H sigil. But using html.heex files it gives the following error:

[Error - 07:32:49] Request textDocument/formatting failed.
  Message: Unable to format due to syntax error
  Code: -32603 
MIX_ENV: test
MIX_TARGET: 

I used the sample code from the elixir formatter docs.

test.html.heex:

<section><h1>   <b><%= @user.name %></b></h1></section>

.formatter.exs

[
  import_deps: [:phoenix],
  plugins: [Phoenix.LiveView.HTMLFormatter],
  inputs: ["*.{heex,ex,exs}", "priv/*/seeds.exs", "{config,lib,test}/**/*.{heex,ex,exs}"]
]

[frankdugan3]

@benvp After upgrading LV, did you run mix deps.compile before mix format?

[benvp]

@frankdugan3 Yeah I did that. Also deleted the build and deps folder. When running mix format directly on the .html.heexfile formatting works. But not when running through VSCode with the Elixir LSP.

[frankdugan3]

@benvp I forgot to mention it, but it also requires Elixir v1.13.4. What version are you running?

[littleStudent]

I have the exact same situation as @benvp described.

• running mix format in the console works
• running the formatter through vscode results in the described error
• I have version 1.13.4 running