Feature Request: Highlight unused values in values.yaml files

[jadefr]

Feature Description

Add the ability to highlight unused values in values.yaml files.

This would help users identify values that are defined but not referenced in any template files. Thus, making it easier to maintain clean and efficient Helm charts.

Implementation Details

The feature would:

• Scan values.yaml files in Helm charts
• Detect .Values.* references in templates, including those used in functions like toYaml
• Highlight unused values with a subtle underline (theme-aware coloring)
• Show hover messages indicating which values are unused

Example

Given a values.yaml:

replicaCount: 3
image:
  repository: nginx
  tag: latest
  unusedSetting: value  # Not used in any of the template files

The extension would:

• Highlight image.unusedSetting
• Show a hover message explaining that the value is unused

Benefits

Helps maintain cleaner Helm charts by identifying unused configurations
Makes review easier by clearly showing what's actually in use

Notes

Already implemented as a standalone VS Code extension at https://github.com/jadefr/helm-highlight-unused-values
Uses VS Code's built-in decoration API for efficient highlighting

[felipecrs]

I think this makes a lot of sense. It's kind of equivalent of detecting unused variables.

[qvalentin]

Thanks for the request.

Seems like this will not be added to helm directly (even if this could make sens imo):

• Lint unused values helm/helm#8822
• Proposal: helm lint --detect-unused-values helm/helm#7285

Its actually not that hard to add it to helm-ls since the templates are already parsed and the information that is required is present. It's just like running references for each value and checking if the result is 0.

So I stared in #177, feel free to test, there are still some todos.

[jadefr]

Hi @qvalentin, thanks for looking into it.

I think it would be better suited to handle the visual styling in helm-ls-vscode.

Considering your feat(values): lint unused values in values.yaml, the VSCode extension could listen for DiagnosticTagUnnecessary and apply the highlighted decorations to make unused values more visible.

This approach would:
• Keep the language server editor-agnostic
• Allow VSCode-specific styling that follows VSCode's design patterns
• Let other editors handle the diagnostics in their own way

[jadefr]

Hi @qvalentin,

I just created feat: add visual highlighting for unused values in YAML files in helm-ls-vscode.

I've tested it and seems to be working fine.

Let me know your opinion.

[Y0-L0]

The same problem of unused (and undefined) variables has been nagging me for quite a while.

But I've approached it from a linter perspective instead of a language server. Partially because I have zero experience with the LSP protocol, treesitter...

Maybe it's interesting to you as a complementary piece.

I'd be happy to integrate some parts of it or just some ideas from it here, but after looking at the linked PR, I must admit that I'm quite out of my depth and don't understand much of your PR. 😅

https://github.com/Y0-L0/helm-snoop