Index: src/wp-includes/comment.php
===================================================================
--- src/wp-includes/comment.php	(revision 26486)
+++ src/wp-includes/comment.php	(working copy)
@@ -44,12 +44,21 @@
 	if ( 1 == get_option('comment_moderation') )
 		return false; // If moderation is set to manual
 
+	/** This filter is documented in wp-includes/comment-template.php */
 	$comment = apply_filters( 'comment_text', $comment );
 
 	// Check # of external links
 	if ( $max_links = get_option( 'comment_max_links' ) ) {
 		$num_links = preg_match_all( '/<a [^>]*href/i', $comment, $out );
-		$num_links = apply_filters( 'comment_max_links_url', $num_links, $url ); // provide for counting of $url as a link
+		/**
+		 * Filter the maximum number of links allowed in a comment.
+		 *
+		 * @since 3.0.0
+		 *
+		 * @param int    $num_links The number of links allowed.
+		 * @param string $url       Comment author's URL. Included in allowed links total.
+		 */
+		$num_links = apply_filters( 'comment_max_links_url', $num_links, $url );
 		if ( $num_links >= $max_links )
 			return false;
 	}
@@ -147,7 +156,14 @@
 		}
 	}
 
-	$_comment = apply_filters('get_comment', $_comment);
+	/**
+	 * Fires after a comment is retrieved.
+	 *
+	 * @since 2.3.0
+	 *
+	 * @param mixed $_comment Comment data.
+	 */
+	$_comment = apply_filters( 'get_comment', $_comment );
 
 	if ( $output == OBJECT ) {
 		return $_comment;
@@ -251,6 +267,13 @@
 		$this->meta_query = new WP_Meta_Query();
 		$this->meta_query->parse_query_vars( $this->query_vars );
 
+		/**
+		 * Fires before comments are retrieved.
+		 *
+		 * @since 3.1.0
+		 *
+		 * @param WP_Comment_Query &$this Current instance of WP_Comment_Query, passed by reference.
+		 */
 		do_action_ref_array( 'pre_get_comments', array( &$this ) );
 		extract( $this->query_vars, EXTR_SKIP );
 
@@ -376,6 +399,14 @@
 		}
 
 		$pieces = array( 'fields', 'join', 'where', 'orderby', 'order', 'limits', 'groupby' );
+		/**
+		 * Filter the comment query clauses.
+		 *
+		 * @since 3.1.0
+		 *
+		 * @param array            $pieces A compacted array of comment query clauses.
+		 * @param WP_Comment_Query &$this  Current instance of WP_Comment_Query, passed by reference.
+		 */
 		$clauses = apply_filters_ref_array( 'comments_clauses', array( compact( $pieces ), &$this ) );
 		foreach ( $pieces as $piece )
 			$$piece = isset( $clauses[ $piece ] ) ? $clauses[ $piece ] : '';
@@ -389,6 +420,14 @@
 			return $wpdb->get_var( $query );
 
 		$comments = $wpdb->get_results( $query );
+		/**
+		 * Filter the comment query results.
+		 *
+		 * @since 3.1.0
+		 *
+		 * @param array            $comments An array of comments.
+		 * @param WP_Comment_Query &$this    Current instance of WP_Comment_Query, passed by reference.
+		 */
 		$comments = apply_filters_ref_array( 'the_comments', array( $comments, &$this ) );
 
 		wp_cache_add( $cache_key, $comments, 'comment' );
@@ -629,7 +668,14 @@
 	if ( $user->exists() )
 		return;
 
-	$comment_cookie_lifetime = apply_filters('comment_cookie_lifetime', 30000000);
+	/**
+	 * Filter the lifetime of the comment cookie in seconds.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @param int $seconds Comment cookie lifetime. Default 30000000.
+	 */
+	$comment_cookie_lifetime = apply_filters( 'comment_cookie_lifetime', 30000000 );
 	setcookie('comment_author_' . COOKIEHASH, $comment->comment_author, time() + $comment_cookie_lifetime, COOKIEPATH, COOKIE_DOMAIN);
 	setcookie('comment_author_email_' . COOKIEHASH, $comment->comment_author_email, time() + $comment_cookie_lifetime, COOKIEPATH, COOKIE_DOMAIN);
 	setcookie('comment_author_url_' . COOKIEHASH, esc_url($comment->comment_author_url), time() + $comment_cookie_lifetime, COOKIEPATH, COOKIE_DOMAIN);
@@ -644,22 +690,52 @@
  * @since 2.0.4
  */
 function sanitize_comment_cookies() {
-	if ( isset($_COOKIE['comment_author_'.COOKIEHASH]) ) {
-		$comment_author = apply_filters('pre_comment_author_name', $_COOKIE['comment_author_'.COOKIEHASH]);
+	if ( isset( $_COOKIE['comment_author_' . COOKIEHASH] ) ) {
+		/**
+		 * Filter the comment author's name cookie before it is set.
+		 *
+		 * When this filter hook is evaluated in wp_filter_comment(),
+		 * the comment author's name string is passed.
+		 *
+		 * @since 1.5.2
+		 *
+		 * @param string $author_cookie The comment author name cookie.
+		 */
+		$comment_author = apply_filters( 'pre_comment_author_name', $_COOKIE['comment_author_' . COOKIEHASH] );
 		$comment_author = wp_unslash($comment_author);
 		$comment_author = esc_attr($comment_author);
-		$_COOKIE['comment_author_'.COOKIEHASH] = $comment_author;
+		$_COOKIE['comment_author_' . COOKIEHASH] = $comment_author;
 	}
 
-	if ( isset($_COOKIE['comment_author_email_'.COOKIEHASH]) ) {
-		$comment_author_email = apply_filters('pre_comment_author_email', $_COOKIE['comment_author_email_'.COOKIEHASH]);
+	if ( isset( $_COOKIE['comment_author_email_' . COOKIEHASH] ) ) {
+		/**
+		 * Filter the comment author's email cookie before it is set.
+		 *
+		 * When this filter hook is evaluated in wp_filter_comment(),
+		 * the comment author's email string is passed.
+		 *
+		 * @since 1.5.2
+		 *
+		 * @param string $author_email_cookie The comment author email cookie.
+		 */
+		$comment_author_email = apply_filters( 'pre_comment_author_email', $_COOKIE['comment_author_email_' . COOKIEHASH] );
 		$comment_author_email = wp_unslash($comment_author_email);
 		$comment_author_email = esc_attr($comment_author_email);
 		$_COOKIE['comment_author_email_'.COOKIEHASH] = $comment_author_email;
 	}
 
-	if ( isset($_COOKIE['comment_author_url_'.COOKIEHASH]) ) {
-		$comment_author_url = apply_filters('pre_comment_author_url', $_COOKIE['comment_author_url_'.COOKIEHASH]);
+	if ( isset( $_COOKIE['comment_author_url_' . COOKIEHASH] ) ) {
+		/**
+		 * Filter the comment author's URL cookie before it is set.
+		 *
+		 * When this filter hook is evaluated in wp_filter_comment(),
+		 * the comment author's URL string is passed.
+		 *
+		 * @since 1.5.2
+		 *
+		 * @param string $author_url_cookie The comment author URL cookie.
+		 */
+		$comment_author_url = apply_filters( 'pre_comment_author_url', $_COOKIE['comment_author_url_' . COOKIEHASH] );
 		$comment_author_url = wp_unslash($comment_author_url);
 		$_COOKIE['comment_author_url_'.COOKIEHASH] = $comment_author_url;
 	}
@@ -688,6 +764,13 @@
 		$dupe .= $wpdb->prepare( "OR comment_author_email = %s ", wp_unslash( $comment_author_email ) );
 	$dupe .= $wpdb->prepare( ") AND comment_content = %s LIMIT 1", wp_unslash( $comment_content ) );
 	if ( $wpdb->get_var($dupe) ) {
+		/**
+		 * Fires when a duplicate comment is detected.
+		 *
+		 * @since 3.0.0
+		 *
+		 * @param array $commentdata Comment data.
+		 */
 		do_action( 'comment_duplicate_trigger', $commentdata );
 		if ( defined('DOING_AJAX') )
 			die( __('Duplicate comment detected; it looks as though you&#8217;ve already said that!') );
@@ -695,6 +778,17 @@
 		wp_die( __('Duplicate comment detected; it looks as though you&#8217;ve already said that!') );
 	}
 
+	/**
+	 * Fires before a comment is approved.
+	 *
+	 * Allows checking for comment flooding.
+	 *
+	 * @since 2.3.0
+	 *
+	 * @param string $comment_author_IP    The comment author's IP address.
+	 * @param string $comment_author_email The comment author's email.
+	 * @param string $comment_date_gmt     The GMT date the comment was posted.
+	 */
 	do_action( 'check_comment_flood', $comment_author_IP, $comment_author_email, $comment_date_gmt );
 
 	if ( ! empty( $user_id ) ) {
@@ -705,7 +799,7 @@
 	if ( isset( $user ) && ( $user_id == $post_author || $user->has_cap( 'moderate_comments' ) ) ) {
 		// The author and the admins get respect.
 		$approved = 1;
-	 } else {
+	} else {
 		// Everyone else's comments will be checked.
 		if ( check_comment($comment_author, $comment_author_email, $comment_author_url, $comment_content, $comment_author_IP, $comment_agent, $comment_type) )
 			$approved = 1;
@@ -715,6 +809,14 @@
 			$approved = 'spam';
 	}
 
+	/**
+	 * Filter a comment's approval status before it is set.
+	 *
+	 * @since 2.1.0
+	 *
+	 * @param bool|string $approved    The approval status. Accepts 1, 0, or 'spam'.
+	 * @param array       $commentdata Comment data.
+	 */
 	$approved = apply_filters( 'pre_comment_approved', $approved, $commentdata );
 	return $approved;
 }
@@ -744,9 +846,26 @@
 	if ( $lasttime = $wpdb->get_var( $wpdb->prepare( "SELECT `comment_date_gmt` FROM `$wpdb->comments` WHERE `comment_date_gmt` >= %s AND ( `comment_author_IP` = %s OR `comment_author_email` = %s ) ORDER BY `comment_date_gmt` DESC LIMIT 1", $hour_ago, $ip, $email ) ) ) {
 		$time_lastcomment = mysql2date('U', $lasttime, false);
 		$time_newcomment  = mysql2date('U', $date, false);
-		$flood_die = apply_filters('comment_flood_filter', false, $time_lastcomment, $time_newcomment);
+		/**
+		 * Filter the comment flood status.
+		 *
+		 * @since 2.1.0
+		 *
+		 * @param bool $bool             Whether a comment flood is occurring. Default false.
+		 * @param int  $time_lastcomment Timestamp of when the last comment was posted.
+		 * @param int  $time_newcomment  Timestamp of when the new comment was posted.
+		 */
+		$flood_die = apply_filters( 'comment_flood_filter', false, $time_lastcomment, $time_newcomment );
 		if ( $flood_die ) {
-			do_action('comment_flood_trigger', $time_lastcomment, $time_newcomment);
+			/**
+			 * Fires before comment flood message is triggered.
+			 *
+			 * @since 1.5.2
+			 *
+			 * @param int $time_lastcomment Timestamp of when the last comment was posted.
+			 * @param int $time_newcomment  Timestamp of when the new comment was posted.
+			 */
+			do_action( 'comment_flood_trigger', $time_lastcomment, $time_newcomment );
 
 			if ( defined('DOING_AJAX') )
 				die( __('You are posting comments too quickly. Slow down.') );
@@ -902,7 +1021,19 @@
  * @return bool True if comment contains blacklisted content, false if comment does not
  */
 function wp_blacklist_check($author, $email, $url, $comment, $user_ip, $user_agent) {
-	do_action('wp_blacklist_check', $author, $email, $url, $comment, $user_ip, $user_agent);
+	/**
+	 * Fires before the comment is tested for blacklisted characters or words.
+	 *
+	 * @since 1.5.2
+	 *
+	 * @param string $author     Comment author.
+	 * @param string $email      Comment author's email.
+	 * @param string $url        Comment author's URL.
+	 * @param string $comment    Comment content.
+	 * @param string $user_ip    Comment author's IP address.
+	 * @param string $user_agent Comment author's browser user agent.
+	 */
+	do_action( 'wp_blacklist_check', $author, $email, $url, $comment, $user_ip, $user_agent );
 
 	$mod_keys = trim( get_option('blacklist_keys') );
 	if ( '' == $mod_keys )
@@ -954,7 +1085,15 @@
 
 	$post_id = (int) $post_id;
 
-	$stats = apply_filters('wp_count_comments', array(), $post_id);
+	/**
+	 * Filter the comments count for the given post.
+	 *
+	 * @since 2.7.0
+	 *
+	 * @param array $count   An empty array.
+	 * @param int   $post_id The post ID.
+	 */
+	$stats = apply_filters( 'wp_count_comments', array(), $post_id );
 	if ( !empty($stats) )
 		return $stats;
 
@@ -1019,7 +1158,14 @@
 	if ( !$force_delete && EMPTY_TRASH_DAYS && !in_array( wp_get_comment_status($comment_id), array( 'trash', 'spam' ) ) )
 		return wp_trash_comment($comment_id);
 
-	do_action('delete_comment', $comment_id);
+	/**
+	 * Fires immediately before a comment is deleted from the database.
+	 *
+	 * @since 1.2.1
+	 *
+	 * @param int $comment_id The comment ID.
+	 */
+	do_action( 'delete_comment', $comment_id );
 
 	// Move children up a level.
 	$children = $wpdb->get_col( $wpdb->prepare("SELECT comment_ID FROM $wpdb->comments WHERE comment_parent = %d", $comment_id) );
@@ -1035,15 +1181,31 @@
 
 	if ( ! $wpdb->delete( $wpdb->comments, array( 'comment_ID' => $comment_id ) ) )
 		return false;
-	do_action('deleted_comment', $comment_id);
 
+	/**
+	 * Fires immediately after a comment is deleted from the database.
+	 *
+	 * @since 2.9.0
+	 *
+	 * @param int $comment_id The comment ID.
+	 */
+	do_action( 'deleted_comment', $comment_id );
+
 	$post_id = $comment->comment_post_ID;
 	if ( $post_id && $comment->comment_approved == 1 )
 		wp_update_comment_count($post_id);
 
 	clean_comment_cache($comment_id);
 
-	do_action('wp_set_comment_status', $comment_id, 'delete');
+	/**
+	 * Fires immediately before changing the comment's status to 'delete'.
+	 *
+	 * @since 1.5.2
+	 *
+	 * @param int    $comment_id The comment ID.
+	 * @param string $status     The new 'delete' comment status.
+	 */
+	do_action( 'wp_set_comment_status', $comment_id, 'delete' );
 	wp_transition_comment_status('delete', $comment->comment_approved, $comment);
 	return true;
 }
@@ -1068,12 +1230,27 @@
 	if ( !$comment = get_comment($comment_id) )
 		return false;
 
-	do_action('trash_comment', $comment_id);
+	/**
+	 * Fires immediately before a comment is sent to the Trash.
+	 *
+	 * @since 2.9.0
+	 *
+	 * @param int $comment_id The comment ID.
+	 */
+	do_action( 'trash_comment', $comment_id );
 
 	if ( wp_set_comment_status($comment_id, 'trash') ) {
 		add_comment_meta($comment_id, '_wp_trash_meta_status', $comment->comment_approved);
 		add_comment_meta($comment_id, '_wp_trash_meta_time', time() );
-		do_action('trashed_comment', $comment_id);
+
+		/**
+		 * Fires immediately after a comment is sent to Trash.
+		 *
+		 * @since 2.9.0
+		 *
+		 * @param int $comment_id The comment ID.
+		 */
+		do_action( 'trashed_comment', $comment_id );
 		return true;
 	}
 
@@ -1094,7 +1271,14 @@
 	if ( ! (int)$comment_id )
 		return false;
 
-	do_action('untrash_comment', $comment_id);
+	/**
+	 * Fires immediately before a comment is restored from Trash.
+	 *
+	 * @since 2.9.0
+	 *
+	 * @param int $comment_id The comment ID.
+	 */
+	do_action( 'untrash_comment', $comment_id );
 
 	$status = (string) get_comment_meta($comment_id, '_wp_trash_meta_status', true);
 	if ( empty($status) )
@@ -1103,7 +1287,14 @@
 	if ( wp_set_comment_status($comment_id, $status) ) {
 		delete_comment_meta($comment_id, '_wp_trash_meta_time');
 		delete_comment_meta($comment_id, '_wp_trash_meta_status');
-		do_action('untrashed_comment', $comment_id);
+		/**
+		 * Fires immediately after a comment is restored from Trash.
+		 *
+		 * @since 2.9.0
+		 *
+		 * @param int $comment_id The comment ID.
+		 */
+		do_action( 'untrashed_comment', $comment_id );
 		return true;
 	}
 
@@ -1124,11 +1315,25 @@
 	if ( !$comment = get_comment($comment_id) )
 		return false;
 
-	do_action('spam_comment', $comment_id);
+	/**
+	 * Fires immediately before a comment is marked as Spam.
+	 *
+	 * @since 2.9.0
+	 *
+	 * @param int $comment_id The comment ID.
+	 */
+	do_action( 'spam_comment', $comment_id );
 
 	if ( wp_set_comment_status($comment_id, 'spam') ) {
 		add_comment_meta($comment_id, '_wp_trash_meta_status', $comment->comment_approved);
-		do_action('spammed_comment', $comment_id);
+		/**
+		 * Fires immediately after a comment is marked as Spam.
+		 *
+		 * @since 2.9.0
+		 *
+		 * @param int $comment_id The comment ID.
+		 */
+		do_action( 'spammed_comment', $comment_id );
 		return true;
 	}
 
@@ -1149,7 +1354,14 @@
 	if ( ! (int)$comment_id )
 		return false;
 
-	do_action('unspam_comment', $comment_id);
+	/**
+	 * Fires immediately before a comment is unmarked as Spam.
+	 *
+	 * @since 2.9.0
+	 *
+	 * @param int $comment_id The comment ID.
+	 */
+	do_action( 'unspam_comment', $comment_id );
 
 	$status = (string) get_comment_meta($comment_id, '_wp_trash_meta_status', true);
 	if ( empty($status) )
@@ -1157,7 +1369,14 @@
 
 	if ( wp_set_comment_status($comment_id, $status) ) {
 		delete_comment_meta($comment_id, '_wp_trash_meta_status');
-		do_action('unspammed_comment', $comment_id);
+		/**
+		 * Fires immediately after a comment is unmarked as Spam.
+		 *
+		 * @since 2.9.0
+		 *
+		 * @param int $comment_id The comment ID.
+		 */
+		do_action( 'unspammed_comment', $comment_id );
 		return true;
 	}
 
@@ -1214,8 +1433,11 @@
  * @param object $comment Comment data.
  */
 function wp_transition_comment_status($new_status, $old_status, $comment) {
-	// Translate raw statuses to human readable formats for the hooks
-	// This is not a complete list of comment status, it's only the ones that need to be renamed
+	/*
+	 * Translate raw statuses to human readable formats for the hooks.
+	 * This is not a complete list of comment status, it's only the ones
+	 * that need to be renamed
+	 */
 	$comment_statuses = array(
 		0         => 'unapproved',
 		'hold'    => 'unapproved', // wp_set_comment_status() uses "hold"
@@ -1227,10 +1449,43 @@
 
 	// Call the hooks
 	if ( $new_status != $old_status ) {
-		do_action('transition_comment_status', $new_status, $old_status, $comment);
-		do_action("comment_{$old_status}_to_{$new_status}", $comment);
+		/**
+		 * Fires when the comment status is in transition.
+		 *
+		 * @since 2.7.0
+		 *
+		 * @param int|string $new_status The new comment status.
+		 * @param int|string $old_status The old comment status.
+		 * @param object     $comment    The comment data.
+		 */
+		do_action( 'transition_comment_status', $new_status, $old_status, $comment );
+		/**
+		 * Fires when the comment status is in transition from one specific status to another.
+		 *
+		 * The dynamic portions of the hook name, $old_status, and $new_status,
+		 * refer to the old and new comment statuses.
+		 *
+		 * @since 2.7.0
+		 *
+		 * @param object $comment Comment object.
+		 */
+		do_action( "comment_{$old_status}_to_{$new_status}", $comment );
 	}
-	do_action("comment_{$new_status}_{$comment->comment_type}", $comment->comment_ID, $comment);
+	/**
+	 * Fires when the statuses of a specific comment type is in transition.
+	 *
+	 * The dynamic portions of the hook name, $new_status, and $comment->comment_type,
+	 * refer to the new comment status, and the type of comment, respectively.
+	 *
+	 * Typical comment types include an empty string (standard comment), 'pingback',
+	 * or 'trackback'.
+	 *
+	 * @since 2.7.0
+	 *
+	 * @param int $comment_ID The comment ID.
+	 * @param obj $comment    Comment object.
+	 */
+	do_action( "comment_{$new_status}_{$comment->comment_type}", $comment->comment_ID, $comment );
 }
 
 /**
@@ -1260,7 +1515,16 @@
 	if ( isset($_COOKIE['comment_author_url_'.COOKIEHASH]) )
 		$comment_author_url = $_COOKIE['comment_author_url_'.COOKIEHASH];
 
-	return apply_filters('wp_get_current_commenter', compact('comment_author', 'comment_author_email', 'comment_author_url'));
+	/**
+	 * Filter the current commenter's name, email, and URL.
+	 *
+	 * @since 3.1.0
+	 *
+	 * @param string $comment_author       Comment author's name.
+	 * @param string $comment_author_email Comment author's email.
+	 * @param string $comment_author_url   Comment author's URL.
+	 */
+	return apply_filters( 'wp_get_current_commenter', compact('comment_author', 'comment_author_email', 'comment_author_url') );
 }
 
 /**
@@ -1305,8 +1569,17 @@
 		wp_update_comment_count($comment_post_ID);
 
 	$comment = get_comment($id);
-	do_action('wp_insert_comment', $id, $comment);
 
+	/**
+	 * Fires immediately after a comment is inserted into the database.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @param int $id      The comment ID.
+	 * @param obj $comment Comment object.
+	 */
+	do_action( 'wp_insert_comment', $id, $comment );
+
 	wp_cache_set( 'last_changed', microtime(), 'comment' );
 
 	return $id;
@@ -1320,34 +1593,64 @@
  * filtering the same comment more than once.
  *
  * @since 2.0.0
- * @uses apply_filters() Calls 'pre_user_id' hook on comment author's user ID
- * @uses apply_filters() Calls 'pre_comment_user_agent' hook on comment author's user agent
- * @uses apply_filters() Calls 'pre_comment_author_name' hook on comment author's name
- * @uses apply_filters() Calls 'pre_comment_content' hook on the comment's content
- * @uses apply_filters() Calls 'pre_comment_user_ip' hook on comment author's IP
- * @uses apply_filters() Calls 'pre_comment_author_url' hook on comment author's URL
- * @uses apply_filters() Calls 'pre_comment_author_email' hook on comment author's email address
  *
  * @param array $commentdata Contains information on the comment.
  * @return array Parsed comment information.
  */
 function wp_filter_comment($commentdata) {
-	if ( isset($commentdata['user_ID']) )
-		$commentdata['user_id'] = apply_filters('pre_user_id', $commentdata['user_ID']);
-	elseif ( isset($commentdata['user_id']) )
-		$commentdata['user_id'] = apply_filters('pre_user_id', $commentdata['user_id']);
-	$commentdata['comment_agent']        = apply_filters('pre_comment_user_agent', ( isset( $commentdata['comment_agent'] ) ? $commentdata['comment_agent'] : '' ) );
-	$commentdata['comment_author']       = apply_filters('pre_comment_author_name', $commentdata['comment_author']);
-	$commentdata['comment_content']      = apply_filters('pre_comment_content', $commentdata['comment_content']);
-	$commentdata['comment_author_IP']    = apply_filters('pre_comment_user_ip', $commentdata['comment_author_IP']);
-	$commentdata['comment_author_url']   = apply_filters('pre_comment_author_url', $commentdata['comment_author_url']);
-	$commentdata['comment_author_email'] = apply_filters('pre_comment_author_email', $commentdata['comment_author_email']);
+	if ( isset( $commentdata['user_ID'] ) ) {
+		/**
+		 * Filter the comment author's user id before it is set.
+		 *
+		 * The first time this filter is evaluated, 'user_ID' is checked
+		 * (for back-compat), followed by the standard 'user_id' value.
+		 *
+		 * @since 1.5.2
+		 *
+		 * @param int $user_ID The comment author's user ID.
+		 */
+		$commentdata['user_id'] = apply_filters( 'pre_user_id', $commentdata['user_ID'] );
+	} elseif ( isset( $commentdata['user_id'] ) ) {
+		/** This filter is documented in wp-includes/comment.php */
+		$commentdata['user_id'] = apply_filters( 'pre_user_id', $commentdata['user_id'] );
+	}
+
+	/**
+	 * Filter the comment author's browser user agent before it is set.
+	 *
+	 * @since 1.5.2
+	 *
+	 * @param int $comment_agent The comment author's browser user agent.
+	 */
+	$commentdata['comment_agent'] = apply_filters( 'pre_comment_user_agent', ( isset( $commentdata['comment_agent'] ) ? $commentdata['comment_agent'] : '' ) );
+	/** This filter is documented in wp-includes/comment.php */
+	$commentdata['comment_author'] = apply_filters( 'pre_comment_author_name', $commentdata['comment_author'] );
+	/**
+	 * Filter the comment content before it is set.
+	 *
+	 * @since 1.5.2
+	 *
+	 * @param int $comment_content The comment content.
+	 */
+	$commentdata['comment_content'] = apply_filters( 'pre_comment_content', $commentdata['comment_content'] );
+	/**
+	 * Filter the comment author's IP before it is set.
+	 *
+	 * @since 1.5.2
+	 *
+	 * @param int $comment_author_ip The comment author's IP.
+	 */
+	$commentdata['comment_author_IP'] = apply_filters( 'pre_comment_user_ip', $commentdata['comment_author_IP'] );
+	/** This filter is documented in wp-includes/comment.php */
+	$commentdata['comment_author_url'] = apply_filters( 'pre_comment_author_url', $commentdata['comment_author_url'] );
+	/** This filter is documented in wp-includes/comment.php */
+	$commentdata['comment_author_email'] = apply_filters( 'pre_comment_author_email', $commentdata['comment_author_email'] );
 	$commentdata['filtered'] = true;
 	return $commentdata;
 }
 
 /**
- * Whether comment should be blocked because of comment flood.
+ * Whether a comment should be blocked because of comment flood.
  *
  * @since 2.1.0
  *
@@ -1381,7 +1684,14 @@
  * @return int The ID of the comment after adding.
  */
 function wp_new_comment( $commentdata ) {
-	$commentdata = apply_filters('preprocess_comment', $commentdata);
+	/**
+	 * Filter a comment's data before it is sanitized and inserted into the database.
+	 *
+	 * @since 1.5.2
+	 *
+	 * @param int|string $commentdata The comment data.
+	 */
+	$commentdata = apply_filters( 'preprocess_comment', $commentdata );
 
 	$commentdata['comment_post_ID'] = (int) $commentdata['comment_post_ID'];
 	if ( isset($commentdata['user_ID']) )
@@ -1405,7 +1715,15 @@
 
 	$comment_ID = wp_insert_comment($commentdata);
 
-	do_action('comment_post', $comment_ID, $commentdata['comment_approved']);
+	/**
+	 * Fires immediately after a comment is inserted into the database.
+	 *
+	 * @since 1.2.1
+	 *
+	 * @param int $comment_ID       The comment ID.
+	 * @param int $comment_approved 1 (true) if the comment is approved, 0 (false) if not.
+	 */
+	do_action( 'comment_post', $comment_ID, $commentdata['comment_approved'] );
 
 	if ( 'spam' !== $commentdata['comment_approved'] ) { // If it's spam save it silently for later crunching
 		if ( '0' == $commentdata['comment_approved'] ) {
@@ -1475,7 +1793,18 @@
 
 	$comment = get_comment($comment_id);
 
-	do_action('wp_set_comment_status', $comment_id, $comment_status);
+	/**
+	 * Fires after a comment status has been updated in the database.
+	 *
+	 * The hook also fires immediately before comment status transition hooks are fired.
+	 *
+	 * @since 1.5.2
+	 *
+	 * @param int         $comment_id     The comment ID.
+	 * @param string|bool $comment_status The comment status. Possible values include 'hold',
+	 *                                    'approve', 'spam', 'trash', or false.
+	 */
+	do_action( 'wp_set_comment_status', $comment_id, $comment_status );
 	wp_transition_comment_status($comment_status, $comment_old->comment_approved, $comment);
 
 	wp_update_comment_count($comment->comment_post_ID);
@@ -1516,7 +1845,14 @@
 	// Now extract the merged array.
 	extract(wp_unslash($commentarr), EXTR_SKIP);
 
-	$comment_content = apply_filters('comment_save_pre', $comment_content);
+	/**
+	 * Filter the comment content before it is updated in the database.
+	 *
+	 * @since 1.5.2
+	 *
+	 * @param string $comment_content The comment data.
+	 */
+	$comment_content = apply_filters( 'comment_save_pre', $comment_content );
 
 	$comment_date_gmt = get_gmt_from_date($comment_date);
 
@@ -1532,7 +1868,16 @@
 
 	clean_comment_cache($comment_ID);
 	wp_update_comment_count($comment_post_ID);
-	do_action('edit_comment', $comment_ID);
+	/**
+	 * Fires immediately after a comment is updated in the database.
+	 *
+	 * The hook also fires immediately before comment status transition hooks are fired.
+	 *
+	 * @since 1.2.1
+	 *
+	 * @param int $comment_ID The comment ID.
+	 */
+	do_action( 'edit_comment', $comment_ID );
 	$comment = get_comment($comment_ID);
 	wp_transition_comment_status($comment->comment_approved, $old_status, $comment);
 	return $rval;
@@ -1629,8 +1974,18 @@
 
 	clean_post_cache( $post );
 
-	do_action('wp_update_comment_count', $post_id, $new, $old);
-	do_action('edit_post', $post_id, $post);
+	/**
+	 * Fires immediately after a post's comment count is updated in the database.
+	 *
+	 * @since 2.3.0
+	 *
+	 * @param int $post_id Post ID.
+	 * @param int $new     The new comment count.
+	 * @param int $old     The old comment count.
+	 */
+	do_action( 'wp_update_comment_count', $post_id, $new, $old );
+	/** This action is documented in wp-includes/post.php */
+	do_action( 'edit_post', $post_id, $post );
 
 	return true;
 }
@@ -1760,15 +2115,19 @@
 		return;
 	}
 
-	if ( empty($post->post_excerpt) )
-		$excerpt = apply_filters('the_content', $post->post_content, $post->ID);
-	else
-		$excerpt = apply_filters('the_excerpt', $post->post_excerpt);
+	if ( empty($post->post_excerpt) ) {
+		/** This filter is documented in wp-admin/post-template.php */
+		$excerpt = apply_filters( 'the_content', $post->post_content, $post->ID );
+	} else {
+		/** This filter is documented in wp-admin/post-template.php */
+		$excerpt = apply_filters( 'the_excerpt', $post->post_excerpt );
+	}
+
 	$excerpt = str_replace(']]>', ']]&gt;', $excerpt);
 	$excerpt = wp_html_excerpt($excerpt, 252, '&#8230;');
 
 	/** This filter is documented in wp-includes/post-template.php */
-	$post_title = apply_filters('the_title', $post->post_title, $post->ID);
+	$post_title = apply_filters( 'the_title', $post->post_title, $post->ID );
 	$post_title = strip_tags($post_title);
 
 	if ( $to_ping ) {
@@ -1851,6 +2210,15 @@
 	endforeach;
 
 	$post_links = array_unique( $post_links );
+	/**
+	 * Fires just before pinging back links found in a post.
+	 *
+	 * @since 2.0.0
+	 *
+	 * @param array &$post_links The post links to be checked, passed by reference.
+	 * @param array &$pung       Whether a link has already been pinged, passed by reference.
+	 * @param int   $post_ID     The post ID.
+	 */
 	do_action_ref_array( 'pre_ping', array( &$post_links, &$pung, $post_ID ) );
 
 	foreach ( (array) $post_links as $pagelinkedto ) {
@@ -1858,13 +2226,25 @@
 
 		if ( $pingback_server_url ) {
 			@ set_time_limit( 60 );
-			 // Now, the RPC call
+			// Now, the RPC call
 			$pagelinkedfrom = get_permalink($post_ID);
 
 			// using a timeout of 3 seconds should be enough to cover slow servers
 			$client = new WP_HTTP_IXR_Client($pingback_server_url);
 			$client->timeout = 3;
-			$client->useragent = apply_filters( 'pingback_useragent', $client->useragent . ' -- WordPress/' . $wp_version, $client->useragent, $pingback_server_url, $pagelinkedto, $pagelinkedfrom);
+			/**
+			 * Filter the user agent sent when pinging-back a URL.
+			 *
+			 * @since 2.9.0
+			 *
+			 * @param string $concat_useragent    The user agent concatenated with ' -- WordPress/'
+			 *                                    and the wordPress version.
+			 * @param string $useragent           The useragent.
+			 * @param string $pingback_server_url The server URL being linked to.
+			 * @param string $pagelinkedto        URL of page linked to.
+			 * @param string $pagelinkedfrom      URL of page linked from.
+			 */
+			$client->useragent = apply_filters( 'pingback_useragent', $client->useragent . ' -- WordPress/' . $wp_version, $client->useragent, $pingback_server_url, $pagelinkedto, $pagelinkedfrom );
 			// when set to true, this outputs debug messages by itself
 			$client->debug = false;
 
@@ -2041,6 +2421,13 @@
 	if ( empty( $posts ) || ! $query->is_singular() || ! get_option( 'close_comments_for_old_posts' ) )
 		return $posts;
 
+	/**
+	 * Filter the list of post types to automatically close comments for.
+	 *
+	 * @since 3.2.0
+	 *
+	 * @param array $post_types An array of registered post types. Default array with 'post'.
+	 */
 	$post_types = apply_filters( 'close_comments_for_post_types', array( 'post' ) );
 	if ( ! in_array( $posts[0]->post_type, $post_types ) )
 		return $posts;
@@ -2080,6 +2467,7 @@
 
 	$post = get_post($post_id);
 
+	/** This filter is documented in wp-includes/comment.php */
 	$post_types = apply_filters( 'close_comments_for_post_types', array( 'post' ) );
 	if ( ! in_array( $post->post_type, $post_types ) )
 		return $open;
