Add declaration-block-no-redundant-longhand-properties autofix

[imvetri]

Describe the issue. Is it a bug or a feature request (new rule, new option, etc.)?

stylelint --fix should convert redundant longhand properties to shorthand

Which rule, if any, is this issue related to?

declaration-block-no-redundant-longhand-properties

What CSS is needed to reproduce this issue?

Following will throw error

  a {
    padding-top: 1px;
    padding-right: 2px;
    padding-bottom: 3px;
    padding-left: 4px; 
}

What stylelint configuration is needed to reproduce this issue?

e.g.

{
  "rules": {
    "declaration-block-no-redundant-longhand-properties": [true, {
        "severity": "warning"
    }],
  }
}

Which version of stylelint are you using?

e.g. 9.2.0

How are you running stylelint: CLI, PostCSS plugin, Node API?

This should work despite the method chose to run stylelint

Does your issue relate to non-standard syntax (e.g. SCSS, nesting, etc.)?

No

What did you expect to happen?

  a {
    padding-top: 1px;
    padding-right: 2px;
    padding-bottom: 3px;
    padding-left: 4px; 
}

should convert above to following

a {
  padding: 1px 2px 3px 4px;
}

What actually happened (e.g. what warnings or errors you are getting)?

No fix currently available

Further notes: Currently this is being discussed in #3068. But that has lot of other rules, so creating a separate one for this rule in case I could write a fix.

[jeddy3]

Currently this is being discussed in #3068.

I've removed this rule from the list in that issue.

But that has lot of other rules, so creating a separate one for this rule in case I could write a fix.

Good idea. Good luck writing the fix too!

[mattxwang]

I know #3326 was closed due to inactivity; is there still interest in writing this autofix? I maintain just-the-docs, and we embarrassingly made a mistake manually fixing this rule (just-the-docs/just-the-docs#1123 and just-the-docs/just-the-docs#1104).

If so, I'd be happy to take a stab at implementing it. I can first base my solution off of @imvetri's existing PR (#3326), unless there have been any developments in utilities/blueprints since then that would make more sense to look at?

[imvetri]

@mattxwang can you confirm if you are also facing the same issue I reported in this comment #3326 (comment)

I didn't continue because I was clueless why I was getting inconsistent evaluation value (I had a suspect on the runner than on my code). feel free to tag me if you also face the same issue.

[mattxwang]

Hey @imvetri, I'm not able to reproduce the flakiness of context.fix - after doing the bare minimum to context.fix to work (add the argument, add meta.fixable, docs, etc.), I can check for context.fix and it's seen by the rule.\

Edit: see #6580