How to check compose.yaml file on VSCode/VSCodium

[truthsword]

Wanted to use Harper extension with docker compose “compose.yaml” files, but there is no identification of obvious spelling errors, etc.

Tried it with a new file (not yaml) and errors were detected, and hoverable. Have I overlooked a setting for checking yaml files?

Thanks!

[yhay81]

You have not missed a VS Code/VSCodium setting: YAML is not currently one of the language IDs supported by harper-ls.

The official supported-languages table includes Markdown, plain text, TOML, and comments in many programming languages, but it does not list yaml:
https://writewithharper.com/docs/integrations/language-server#supported-languages

That is why Harper works when the same content is opened as plain text but does nothing when VS Code identifies compose.yaml as YAML.

As a quick confirmation, click the language mode in the lower-right corner and temporarily change it from YAML to Plain Text. Harper should then lint it. I would not make a permanent files.associations mapping from compose.yaml to plaintext, though, because that disables the YAML/Docker Compose language features and Harper would try to lint YAML keys and other non-prose content.

For a proper solution while retaining Compose validation, Harper needs YAML language support/a YAML parser that extracts only suitable natural-language regions (at minimum comments, and perhaps selected scalar strings). So the practical options today are:

• keep descriptions/prose in a Markdown file that Harper supports;
• temporarily use Plain Text only when proofreading a copied passage;
• open a YAML-language-support feature request (or PR) and state whether you need comments only or scalar values too.

The VS Code extension is powered by harper-ls, so VSCodium behaves the same way; installing another build of the extension will not add YAML support by itself:
https://writewithharper.com/docs/integrations/visual-studio-code