Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
| 1 | <?php  | 
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| 15 | class Tracking { | 
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| 16 | /**  | 
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| 17 | * Slug of the product that we are tracking.  | 
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| 18 | *  | 
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| 19 | * @var string  | 
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| 20 | */  | 
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| 21 | private $product_name;  | 
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| 22 | |||
| 23 | /**  | 
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| 24 | * Connection manager object.  | 
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| 25 | *  | 
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| 26 | * @var Object  | 
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| 27 | */  | 
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| 28 | private $connection;  | 
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| 29 | |||
| 30 | /**  | 
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| 31 | * Creates the Tracking object.  | 
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| 32 | *  | 
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| 33 | * @param String $product_name the slug of the product that we are tracking.  | 
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| 34 | * @param Automattic\Jetpack\Connection\Manager $connection the connection manager object.  | 
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| 35 | */  | 
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| 36 | 	public function __construct( $product_name = 'jetpack', $connection = null ) { | 
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| 44 | |||
| 45 | /**  | 
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| 46 | * Enqueue script necessary for tracking.  | 
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| 47 | */  | 
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| 48 | View Code Duplication | 	public function enqueue_tracks_scripts() { | 
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| 59 | |||
| 60 | /**  | 
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| 61 | * Send an event in Tracks.  | 
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| 62 | *  | 
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| 63 | * @param string $event_type Type of the event.  | 
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| 64 | * @param array $data Data to send with the event.  | 
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| 65 | * @param mixed $user username, user_id, or WP_user object.  | 
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| 66 | */  | 
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| 67 | 	public function record_user_event( $event_type, $data = array(), $user = null ) { | 
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| 88 | |||
| 89 | /**  | 
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| 90 | * Record an event in Tracks - this is the preferred way to record events from PHP.  | 
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| 91 | *  | 
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| 92 | * @param mixed $user username, user_id, or WP_user object.  | 
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| 93 | * @param string $event_name The name of the event.  | 
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| 94 | * @param array $properties Custom properties to send with the event.  | 
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| 95 | * @param int $event_timestamp_millis The time in millis since 1970-01-01 00:00:00 when the event occurred.  | 
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| 96 | *  | 
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| 97 | * @return bool true for success | \WP_Error if the event pixel could not be fired  | 
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| 98 | */  | 
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| 99 | 	public function tracks_record_event( $user, $event_name, $properties = array(), $event_timestamp_millis = false ) { | 
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| 122 | |||
| 123 | /**  | 
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| 124 | * Procedurally build a Tracks Event Object.  | 
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| 125 | * NOTE: Use this only when the simpler Automattic\Jetpack\Tracking->jetpack_tracks_record_event() function won't work for you.  | 
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| 126 | *  | 
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| 127 | * @param WP_user $user WP_user object.  | 
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| 128 | * @param string $event_name The name of the event.  | 
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| 129 | * @param array $properties Custom properties to send with the event.  | 
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| 130 | * @param int $event_timestamp_millis The time in millis since 1970-01-01 00:00:00 when the event occurred.  | 
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| 131 | *  | 
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| 132 | * @return \Jetpack_Tracks_Event|\WP_Error  | 
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| 133 | */  | 
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| 134 | 	private function tracks_build_event_obj( $user, $event_name, $properties = array(), $event_timestamp_millis = false ) { | 
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| 158 | |||
| 159 | /**  | 
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| 160 | * Get the identity to send to tracks.  | 
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| 161 | *  | 
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| 162 | * @param int $user_id The user id of the local user.  | 
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| 163 | *  | 
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| 164 | * @return array $identity  | 
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| 165 | */  | 
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| 166 | 	public function tracks_get_identity( $user_id ) { | 
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| 205 | }  | 
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| 206 | 
This check looks for
@paramannotations where the type inferred by our type inference engine differs from the declared type.It makes a suggestion as to what type it considers more descriptive.
Most often this is a case of a parameter that can be null in addition to its declared types.