Loss of Edited Content in Justfile When Auto-Formatting with Helix

[eli-yip]

Summary

When using Helix (versions 25.01.1 (01fce51c) and 25.01.1 (e7ac2fcd) installed via Homebrew), edited content in a justfile is lost during automatic formatting under specific conditions.

Reproduction Steps

The issue occurs with the following languages.toml configuration:

[[language]]
name = "just"
auto-format = true
formatter = { command = "just", args = ["--dump"] }

1. Create a justfile with the following initial content:

   test:
       echo "test command"

2. Open the justfile in Helix.

3. Edit the file by adding new content, e.g.:

test:
    echo "test command"
  
new-test:
    echo "new test command"

4. Run :fmt or :w in Helix.

5. Observe that the newly added content (new-test section) disappears, reverting the file to its original state:

test:
    echo "test command"

Expected Behavior: The edited content should persist after formatting or saving.

Actual Behavior: The newly added content is lost when :fmt or :w is executed with auto-format = true.

Cases Where the Issue Does Not Occur:

1. When auto-format is set to false in languages.toml and :fmt is executed manually.
2. When creating a new justfile from scratch and formatting it, regardless of the auto-format setting (true or false).

Helix log

No response

Platform

macOS

Terminal Emulator

alacritty 0.15.1 (0c405d5)

Installation Method

source and brew

Helix Version

helix 25.01.1 (01fce51) helix 25.01.1 (e7ac2fc)(Homebrew)

[the-mikedavis]

See #9703. External formatters work by passing the document to the formatter command as stdin and reading the formatted output as stdout and just --dump isn't meant to do that.

[ficd0]

I've solved this problem, solution in #13287