Advanced debugging of all functions attached to a specific filter

list-hooks.php

/**
* Even fancier debug info
* @props @Danijel http://stackoverflow.com/a/26680808/383847
* @since 1.7.7
*/
function list_hooks( $hook = '' ) {
	global $wp_filter;

	$hooks = isset( $wp_filter[$hook] ) ? $wp_filter[$hook] : array();  
	$hooks = call_user_func_array( 'array_merge', $hooks );

	foreach( $hooks as &$item ) {

		// function name as string or static class method eg. 'Foo::Bar'
		if ( is_string( $item['function'] ) ) { 

			try {
				
			   $ref = strpos( $item['function'], '::' ) ? new ReflectionClass( strstr( $item['function'], '::', true ) ) : new ReflectionFunction( $item['function'] );
				$item['file'] = $ref->getFileName();
				$item['line'] = get_class( $ref ) == 'ReflectionFunction' 
					? $ref->getStartLine() 
					: $ref->getMethod( substr( $item['function'], strpos( $item['function'], '::' ) + 2 ) )->getStartLine();

			} catch( Exception $e ){
				$item['error'] = $e->getMessage();
			}
				
		// array( object, method ), array( string object, method ), array( string object, string 'parent::method' )
		} elseif ( is_array( $item['function'] ) ) {

			try {
				$ref = new ReflectionClass( $item['function'][0] );
				$item['file'] = $ref->getFileName();
				$item['line'] = strpos( $item['function'][1], '::' )
				? $ref->getParentClass()->getMethod( substr( $item['function'][1], strpos( $item['function'][1], '::' ) + 2 ) )->getStartLine()
				: $ref->getMethod( $item['function'][1] )->getStartLine();

			} catch( Exception $e ){
				$item['error'] = $e->getMessage();
			}

		// closures
		} elseif ( is_callable( $item['function'] ) ) {     

			try {
				$ref = new ReflectionFunction( $item['function'] );         
				$item['function'] = get_class( $item['function'] );
				$item['file'] = $ref->getFileName();
				$item['line'] = $ref->getStartLine();
			} catch( Exception $e ){
	        		$item['error'] = $e->getMessage();
			}

		}       

		
	}

	return $hooks;
}