declaration-block-no-redundant-longhand-properties: support collapsing and new properties

[Mouvedia]

Reason

see #6958 (comment)

Collapsing

fixes for these properties:

• padding
• margin
• border-radius
• border-width

e.g. for border-radius

border-top-left-radius: 1px;
border-top-right-radius: 4px;
border-bottom-right-radius: 2px;
border-bottom-left-radius: 4px;

/* gets fixed to */

border-radius: 1px 4px 2px;

border-radius: 1px 4px 2px 4px;

/* this fix would be a bonus targetted to previous versions of stylelint */

border-radius: 1px 4px 2px;

New properties

support:

• overflow
• background-position
• border-image-width
• border-inline-width
• border-block-width
• offset-position
• overscroll-behavior

These lists are not exhaustive and may be expanded by the PR submitter(s) if need be.
Id recommend to handle it in several separate PRs.

[ybiquitous]

@Mouvedia Thanks for opening the discussion.

Just to confirm, should we provide this feature as an opt-in or not? I'm a bit concerned if there are any cases where people want to avoid shorthand with fewer values than 4, like border-radius: 1px 4px 2px.

[Mouvedia]

I'm a bit concerned if there are any cases where people want to avoid shorthand with fewer values than 4

The only reasons I can come up with would apply to 4 values as well.
i.e. being explicit, easier to maintain

should we provide this feature as an opt-in or not?

I think it should be automatic if it's easy to implement.
i.e. the logic needs to be shared

[ybiquitous]

Okay, I agree with supporting the collapsing without any option. 👍🏼

[jeddy3]

I believe we're describing our shorthand-property-no-redundant-values rule.

Demo

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[ybiquitous]

Sorry, I missed the existing rule shorthand-property-no-redundant-values. 😓

[jeddy3]

We've a lot of rules and we can't be expected to remember them all 😄

[Mouvedia]

@jeddy3 so the second part—new properties—is dismissed as well?

[jeddy3]

Please open a dedicated new false negatives bug report issue following the conventions for titles and labels.