Fix report() for index/endIndex zero values

[romainmenke]

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

None, but related to #7518 (comment)

Is there anything in the PR that needs further explanation?

a {}

This stylesheet has a selector with a length 1 at the start of a stylesheet.
This is passed to PostCSS as index: 0 and endIndex: 0 since endIndex is exclusive.

However both Stylelint and PostCSS have boolean checks for endIndex instead of a check that it is a number.

So the warning is reported as if no endIndex was set.
This does a fallback to the entire length of the node.

a {}
^  ^

---

PostCSS has already been fixed but awaiting release : postcss/postcss#1932

---

This should have a unit test, but I noticed that there aren't any unit tests for report.mjs with endIndex.

So I wasn't sure on what the best and most succinct test would be here.

[changeset-bot]

🦋 Changeset detected

Latest commit: 847f8f9

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
stylelint	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[ybiquitous]

@romainmenke Thanks for the pull request! In addition to endIndex, does also checking index make sense?

-	} else if (index) {
+	} else if (typeof index === 'number') {

stylelint/lib/utils/report.mjs

Line 105 in b05abc8

} else if (index) {

[romainmenke]

Tested with also a check for index and that seems safe to me, so I've also added this.

I don't think it makes a practical difference because in the absence of a start index there already are fallbacks to the start in PostCSS, so "not specified" is always equal to 0.

But I like the consistency :)

---

I've also updated PostCSS so that the fix is complete.

[ybiquitous]

Thank you. LGTM 👍🏼

Besides, can you add a changelog item according to this PR title?

Fixed: `report()` for `index`/`endIndex` zero values

After adding the item, feel free to merge 👍🏼

[romainmenke]

Thank you for the feedback @ybiquitous 🙇