Review the WordPressVIPMinimum.Performance.BatcacheWhitelistedParams sniff

[jrfnl]

Review the WordPressVIPMinimum.Performance.BatcacheWhitelistedParams sniff for the following in as far as relevant to that sniff:

• Code style independent sniffing / Correct handling of quirky code
  Typical things to add tests for and verify correct handling of:
  • Nested function/closure declarations
  • Nested class declarations
  • Comments in unexpected places
  • Variables being assigned to via list statements
  • Multiline text strings
  • Text strings provided via heredoc/nowdoc
  • Use of short open tags
  • Using PHP close tag as end of statement
  • Inline control structures (without braces)
• Code simplifications which can be made using PHPCSUtils
• Sniff stability improvements which can be made using PHPCSUtils
• Correct handling of modern PHP code
  Typical things to add tests for and verify correct handling of (where applicable):
  • PHP 5.0 Try/catch/finally (PHP 5.5) and exceptions
  • PHP 5.3 Namespaced code vs code in the global namespace
  • PHP 5.3 Use import statements, incl aliasing
  • PHP 5.3 Short ternaries
  • PHP 5.3 Closures, incl closure use
  • PHP 5.4 Short arrays
  • PHP 5.5 Class name resolution using ::class
  • PHP 5.5 List in foreach
  • PHP 5.5/7.0 Generators using yield and yield from
  • PHP 5.6 Constant scalar expressions
  • PHP 5.6 Importing via use function/const
  • PHP 7.0 Null coalesce
  • PHP 7.0 Anonymous classes
  • PHP 7.0 Scalar and return type declarations
  • PHP 7.0 Group use statements
  • PHP 7.1 Short lists
  • PHP 7.1 Keyed lists
  • PHP 7.1 Multi-catch
  • PHP 7.1 Nullable types
  • PHP 7.3 List reference assignments
  • PHP 7.4 arrow functions
  • PHP 7.4 numeric literals with underscores
  • PHP 7.4 null coalesce equals
  • PHP 7.4 Typed properties
  • Various versions: trailing comma's in function calls, group use, function declarations, closure use etc

Other:

• Review violation error vs warning
• Review violation severity
• Review violation message, consider adding a link
• Check open issues related to the sniff
• Review PHPDoc comments

Sniff basics, but changes need to be lined up for next major release:

• Inappropriate use of public properties (Audit Public Sniff Properties #234)
• Modular error codes (unique error code for each distinct message)

Once PHPCS/PHPCSUtils supports this:

• PHP 8.0 Constructor property promotion
• PHP 8.0 Union types
• PHP 8.0 match expressions
• PHP 8.0 Nullsafe operator
• PHP 8.0 Named arguments
• PHP 8.0 Single token namespaced names

[jrfnl]

While this is a sniff which isn't used for Go, this sniff is a good candidate for improvement in the short term.

A quick scan leaves me with the following action list:

• Fix class documentation.
• Also check for the index keys with $_REQUEST, $GLOBALS['_GET'] and $GLOBALS['_REQUEST']. (fixes false negatives)
• Stricter checking - make sure the index key is just and only the text string, don't base the warning just off the first non empty token in the key. (fixes false positives)
• Ignore "use" in isset() or empty() to reduce noise.
• Small performance improvements by not using array_merge or in_array when not necessary.
• Deprecated the public property, add a private property for the same and throw a warning if the public property is used in a custom ruleset (i.e. not the same as the private property content).

I'd like to use a more friendly name for the private property.
@rebeccahum @GaryJones Is there a public link with more information about the background of this sniff which I could use to come up with a better name for the property ?

[GaryJones]

Closing as this sniff will be removed in an upcoming version of VIPCS.