custom-property-no-missing-var-function false positives?

What steps are needed to reproduce the bug?

We use Less, and our comment headers in each file are tripping up on custom-property-no-missing-var-function.

//
//  STACK OVERFLOW
//  THE COMPLETE STANDALONE STACKS
//
//  This CSS comes from Stacks, our CSS & Pattern library for rapidly building
//  Stack Overflow. For documentation of all these classes and how to contribute,
//  visit https://stackoverflow.design/
//
//  This is where all the magic happens.
//
//  ============================================================================
@import "stacks-static.less";
@import "stacks-dynamic.less";

What Stylelint configuration is needed to reproduce the bug?

{
  "extends": "stylelint-config-standard",
  "rules": {
    "indentation": 4,
    "max-empty-lines": 2,
    "no-invalid-double-slash-comments": null,
    "rule-empty-line-before": null,
    "at-rule-empty-line-before": null,
    "declaration-empty-line-before": null,
    "selector-pseudo-element-colon-notation": "single",
    "no-descending-specificity": null,
    "function-whitespace-after": null,
    "no-invalid-position-at-import-rule": null,
    "string-quotes": null,
    "custom-property-no-missing-var-function": null,
    "alpha-value-notation": null,
    "max-line-length": null,
    "hue-degree-notation": null,
    "color-function-notation": null,
    "selector-class-pattern": null,
    "custom-property-pattern": null,
    "value-no-vendor-prefix": null,
    "property-no-vendor-prefix": null,
    "selector-no-vendor-prefix": null,
    "declaration-block-trailing-semicolon": null,
    "block-closing-brace-newline-before": null,
    "block-closing-brace-empty-line-before": null,
    "declaration-block-no-redundant-longhand-properties": null,
    "selector-disallowed-list": [
      "/[.#]js-/",
      {
        "message": "js-* selectors can’t have visual styling. https://stackoverflow.design/product/guidelines/javascript/#javascript-classnames"
      }
    ]
  }
}

How did you run Stylelint?

Visual Studio plugin

Which version of Stylelint are you using?

14.0.1

What did you expect to happen?

By setting custom-property-no-missing-var-function to null, I expect this failure to be ignored as it was prior to 14.0.0

What actually happened?

Unknown rule custom-property-no-missing-var-function. [1,1]

Does the bug relate to non-standard syntax?

No response

Proposal to fix the bug

No response

[aaronshekey]

Ah, yep. A hard restart of Visual Studio Code cleared up this issue. Closing!

[jeddy3]

@aaronshekey Thanks for the report. As @alexander-akait said, this usually happens because an older version of Stylelint is being used somewhere.

Do you get the error when using Stylelint via the CLI?

If not, then VS Code is using an older version and you should:

1. use the official extension (there’s quite a few unofficial ones in the marketplace): https://marketplace.visualstudio.com/items?itemName=stylelint.vscode-stylelint
2. ensure the extension is up to date
3. restart VS Code
4. uninstall any globally installed version of Stylelint

Let us know if that works for you or not, and we’ll go from there.