CronInterval: implement new Sniff::is_in_function_call() method

This fixes some potential false positives.

Includes unit tests.

Author: jrfnl

WordPress/Sniffs/WP/CronIntervalSniff.php

@@ -55,6 +55,15 @@ class CronIntervalSniff extends Sniff {
 		'YEAR_IN_SECONDS'   => 31536000,
 	);
 
+	/**
+	 * Function within which the hook should be found.
+	 *
+	 * @var array
+	 */
+	protected $valid_functions = array(
+		'add_filter' => true,
+	);
+
 	/**
 	 * Returns an array of tokens this test wants to listen for.
 	 *
@@ -82,8 +91,8 @@ public function process_token( $stackPtr ) {
 		}
 
 		// If within add_filter.
-		$functionPtr = $this->phpcsFile->findPrevious( \T_STRING, key( $token['nested_parenthesis'] ) );
-		if ( false === $functionPtr || 'add_filter' !== $this->tokens[ $functionPtr ]['content'] ) {
+		$functionPtr = $this->is_in_function_call( $stackPtr, $this->valid_functions );
+		if ( false === $functionPtr ) {
 			return;
 		}
 
@@ -92,6 +101,11 @@ public function process_token( $stackPtr ) {
 			return;
 		}
 
+		if ( $stackPtr >= $callback['start'] ) {
+			// "cron_schedules" found in the second parameter, not the first.
+			return;
+		}
+
 		// Detect callback function name.
 		$callbackArrayPtr = $this->phpcsFile->findNext( Tokens::$emptyTokens, $callback['start'], ( $callback['end'] + 1 ), true );
 

WordPress/Tests/WP/CronIntervalUnitTest.inc

@@ -52,7 +52,7 @@ add_filter( 'cron_schedules' ); // Ignore, no callback parameter.
 
 add_filter( 'cron_schedules', [ 'Foo', 'my_add_quicklier' ] ); // Error: 5 min.
 
-// Ignore, not our function. Currently gives false positive, will be fixed later when function call detection utility functions are added.
+// Ignore, not our function.
 My_Custom::add_filter( 'cron_schedules', [ 'Foo', 'my_add_quicklier' ] );
 
 // Deal correctly with the WP time constants.
@@ -139,3 +139,8 @@ add_filter( 'cron_schedules', function ( $schedules ) {
 	);
 	return $schedules;
 } ); // Error: 9 min.
+
+Custom::add_filter( 'cron_schedules', array( $class, $method ) ); // OK, not the WP function.
+add_filter( 'some_hook', array( $place, 'cron_schedules' ) ); // OK, not the hook we're looking for.
+add_filter( function() { return get_hook_name('cron_schedules'); }(), array( $class, $method ) ); // OK, nested in another function call.
+

WordPress/Tests/WP/CronIntervalUnitTest.php

@@ -45,7 +45,6 @@ public function getWarningList() {
 			41  => 1,
 			43  => 1,
 			53  => 1,
-			56  => 1, // False positive.
 			67  => 1,
 			76  => 1,
 			85  => 1,