Sniff to check whitespace around namespace separators

[jrfnl]

While working on something else, I suddenly realized that there is no sniff to check the whitespace around namespace separator tokens \ and that some other sniffs get terribly confused and throw false positives/incorrect error messages when they encounter whitespace and/or comments within a namespace name.

namespace MyNS \  WhiteSpace\OK\ NotOK;

class ABC extends \ MyNamespace \ /* comment */ Something \    Other \
    Deeper \ ClassName
{}

I realize it is rare to encounter such code, but it is perfectly valid PHP code and PHP will just ignore the whitespace and comments and function as expected. Also see: https://3v4l.org/EFgCp

While not explicit in the textual guidelines, using whitespace and comments within a namespace name does appear to be forbidden in PSR-2 based on all the example code.

The sniffs which currently throw false positives when they encounter such code - based on a cursory analysis - are PSR2.Classes.ClassDeclaration and Squiz.Classes.ClassDeclaration.

@gsherwood Do you think its a good idea to add a new sniff for this ? I'm thinking Generic.WhiteSpace.NamespaceSeparatorSpacing with a public $ignoreNewlines property which defaults to false.
And if so, should it be added to any of the existing rulesets ?

I'd be happy to create the sniff and fix the other two I mentioned above (I actually already started to do so), but figured this warranted an issue to discuss before I opened a PR.

[gsherwood]

A similar issue was fixed in PSR2.Namespaces.NamespaceDeclaration as part of bug #2095

A sniff sounds like a good idea. Fixes would be great.

[jrfnl]

That might well have been the issue which inspired me to look into the handling of this. Expect some PRs soon.

[jrfnl]

I'm going to close this issue.

I did work on this at the time, but it was more complicated than I anticipated.

All the same, as whitespace and comments within namespaced names will now become a parse error in PHP 8.0, a sniff for this was needed for the PHPCompatibility PHPCS standard anyway and with the benefit of two more years of sniff writing, I have finished the sniff and will pull it to PHPCompatibility in the near future.

It will be available as part of the PHPCompatibility 10.0.0 release.