Implement reusable `PHPCodeSniffer_Sniff_Check` class to replace individual check classes per sniff

[felixarntz]

Is your enhancement related to a problem? Please describe.

The following checks currently rely on an extremely similar class implementation:

• Enqueued_Scripts_In_Footer_Check
• I18n_Usage_Check
• Late_Escaping_Check
• Performant_WP_Query_Params_Check

Implementing a new class for every single sniff check is unnecessarily tedious, and it will just get worse in the future as we add more PHPCS sniff-based checks.

Therefore, we should introduce a single class for that purpose, which can simply be passed the sniff to use in a constructor parameter.

Designs

• Implement a PHPCodeSniffer_Sniff_Check class that extends Abstract_PHP_CodeSniffer_Check.
  • It should have a class property and required constructor parameter array $sniffs.
  • It should implement the get_args() method as follows:
    • Return extensions as "php".
    • Return sniffs as a comma-separated list of $sniffs.
    • Return standard as a comma-separated list of the unique first segments of each element in $sniffs (e.g. for a single sniff "WordPress.DB.SlowDBQuery", it should use "WordPress" as the standard to use).
• Update relevant checks in Abstract_Check_Runner::register_checks() to use instances of the new class, passing the relevant sniffs. At the time of writing, this applies to the following checks:
  • enqueued_scripts_in_footer
  • i18n_usage
  • late_escaping
  • performant_wp_query_params
• Add test coverage for the PHPCodeSniffer_Sniff_Check. It can use any sniff, e.g. one of the ones we already had tests for (like WordPress.WP.I18n), so that we can basically just copy over the tests rather than writing new ones from scratch.
• Remove the dedicated classes for the above checks that were modified as well as their test coverage.

Describe alternatives you've considered

No response

Code of Conduct

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[jjgrainger]

Thanks @felixarntz the AC's look good to me.

I think we might want to consider how additional attributes are added for these checks. I've noted in #203 that the PHPCodeSniffer_Sniff_Check constructor would need to accept a category parameter, but what about any other attributes such as stability flags (#92)?

Although this approach will reduce repeated code it does bring some restrictions. However, we could take this approach for now and adjust as we need.

[felixarntz]

I left a reply to your other comment, for the class here we could use traits probably for both the category and stability.

For stability, we could even consider to always make these PHPCS checks stable for now, since they would always use logic that is already established (e.g. through WPCS) anyway.