Leading comments in .yarnrc.yml are removed when updating catalog dependencies

[literat]

How are you running Renovate?

A Mend.io-hosted app

Which platform you running Renovate on?

GitHub.com

Which version of Renovate are you using?

43.59.0

Please tell us more about your question or problem

When Renovate updates dependency versions inside the catalogs: section of .yarnrc.yml, it strips any YAML comments that appear at the very top of the file (before the first key). Comments located between keys further down in the file are preserved correctly.

Reproduction

The .yarnrc.yml file starts with:

# Path where the downloaded packages are stored on your system.
# @see: https://yarnpkg.com/configuration/yarnrc#cacheFolder
cacheFolder: ./.yarn/cache

After Renovate updates the catalog versions, the PR removes the two leading comment lines entirely:

-# Path where the downloaded packages are stored on your system.
-# @see: https://yarnpkg.com/configuration/yarnrc#cacheFolder
 cacheFolder: ./.yarn/cache

Comments that appear between keys later in the file (e.g. # Compression level employed for zip archives, # Design system tooling) are not affected.

Expected behavior

Leading comments at the top of .yarnrc.yml should be preserved in the same way mid-file comments are.

Workarounds attempted

Adding a --- document start marker before the comments — did not help
Moving the comment inline onto the cacheFolder: value line — works, but degrades readability

Additional context

A similar issue is documented for JSON5 config files (Renovate's own configMigration feature strips JSON5 comments), so this appears to be a broader pattern in how Renovate handles comment preservation across serialization formats.

Logs (if relevant)

Logs

Replace this text with your logs, between the starting and ending triple backticks

[spdiswal]

I have observed the exact same issue for catalog: in pnpm-workspace.yaml.

[RahulGautamSingh]

Sounds legit. PR welcome