Fix $collection->group() for case-sensitive

[distantnative]

This PR …

Fixes

• Fix $collection->group() for case-sensitive
  Collection->group() throws error with $i set to false #5628

Ready?

• Unit tests for fixed bug/feature
• In-code documentation (wherever needed)
• Tests and checks all pass

For review team

• Add changes to release notes draft in Notion
• Add to website docs release checklist (if needed)

[afbora]

Why is the parameter name $i?. I spent a while trying to figure out what $i is for. How about a better variable name?

[lukasbestle]

What about $ignoreCase? It would be a breaking change with PHP named params, but I agree it would be very worth it.

[afbora]

Or may be bool $caseSensitive = false

[distantnative]

@afbora But then it wouldn't be just a breaking change of the parameter name but all existing calls would do exactly the opposite of what they did before

[distantnative]

It gets even messier. Collection has a $caseSensitive class prop. Though this seems to be only used in one test. I am wondering if we should deprecate that to get a bit more clarity.

On the parameter name, I'd go with $caseInsensitive as that's used throughout the Str class.

[distantnative]

Ok, revert... if we rename this parameter, this fix can't be in 3.9.7.

I suggest we merge the fix without the renamed parameter and rename the parameter for v4: #5634