Feature request: add sniff support for constant comments

[rjgwiz]

phpdoc mentions constants under the programming constructs that should be preceded by a DocBlock.

I can't find anyway to enforce docblock comments for constants.

Docblock comments are currently enforceable via ClassCommentSniff, FunctionCommentSniff, VariableCommentSniff, and FileCommentSniff. None seem appropriate to add support for constants (VariableCommentSniff would be the closest, but it extends AbstractVariableSniff and adding T_CONST to the listen list would break a lot of other sniffs, class constants aren't normal variables, and it wouldn't cover defined constants.

Some sniffs exist for constants, for example UpperCaseConstantNameSniff. Any hesitations around adding a new sniff called ConstantCommentSniff? Scope would be the same as UpperCaseConstantNameSniff so any constant defined via the define() function or the const keyword (e.g. class constant).

With buy-in I could work on ConstantCommentSniff and submit a PR when it's ready.

[gsherwood]

I think a ConstantComment sniff sounds like a good idea.

I haven't reviewed the doc comment sniffs because I've been waiting for PSR-5 to be complete so I could (hopefully) standardise the checks instead of using the Squiz-specific ones. That, and a lack of time.

If you want to give any of the comment sniffs a go, please do. Huge bonus if you have it enforce PSR-2's recommendations.

[rjgwiz]

Thank you @gsherwood. I hope to start working on this soon.

[TomasVotruba]

@rjgwiz 👍 You can basically copy https://github.com/Symplify/Symplify/blob/master/packages/CodingStandard/src/Sniffs/Commenting/VarConstantCommentSniff.php + extends a bit to match your needs.

/**
 * @var int
 */
private const VALUE = 10;

It works great with static analysis rule - https://github.com/Symplify/Symplify/blob/master/packages/PHPStanExtensions/src/Rules/Classes/MatchingTypeConstantRule.php, e.g.:

/**
 * @var int
 */
private const VALUE = '10'; // Error!

[jrfnl]

Related to #2222 which will make creating this sniff so much easier ;-)

[rjgwiz]

Thank you both. I plan to get to this in the next week or two.

[TomasVotruba]

@jrfnl Any ETA on that feature coming to tagged version?

[jrfnl]

@TomasVotruba I expect it to be ready for PHPCS 3.5.0 which includes lots of other goodies which will be useful for this too. See #2189

[TomasVotruba]

@jrfnl That would be amazing!

[dereuromark]

I guess this wasnt pursued further so far?
The links above to the existing ones are 404 by now. Maybe someone knows the new URLs?