diff -r 3d4e9c994f10 -r a86126ab1dd4 wp/wp-includes/canonical.php
--- a/wp/wp-includes/canonical.php	Tue Oct 22 16:11:46 2019 +0200
+++ b/wp/wp-includes/canonical.php	Tue Dec 15 13:49:49 2020 +0100
@@ -19,8 +19,8 @@
  *
  * Prevents redirection for feeds, trackbacks, searches, and
  * admin URLs. Does not redirect on non-pretty-permalink-supporting IIS 7+,
- * page/post previews, WP admin, Trackbacks, robots.txt, searches, or on POST
- * requests.
+ * page/post previews, WP admin, Trackbacks, robots.txt, favicon.ico, searches,
+ * or on POST requests.
  *
  * Will also attempt to find the correct link when a user enters a URL that does
  * not exist based on exact WordPress query. Will instead try to parse the URL
@@ -28,46 +28,49 @@
  *
  * @since 2.3.0
  *
- * @global WP_Rewrite $wp_rewrite
- * @global bool $is_IIS
- * @global WP_Query $wp_query
- * @global wpdb $wpdb WordPress database abstraction object.
- * @global WP $wp Current WordPress environment instance.
+ * @global WP_Rewrite $wp_rewrite WordPress rewrite component.
+ * @global bool       $is_IIS
+ * @global WP_Query   $wp_query   WordPress Query object.
+ * @global wpdb       $wpdb       WordPress database abstraction object.
+ * @global WP         $wp         Current WordPress environment instance.
  *
  * @param string $requested_url Optional. The URL that was requested, used to
- *      figure if redirect is needed.
- * @param bool $do_redirect Optional. Redirect to the new URL.
+ *                              figure if redirect is needed.
+ * @param bool   $do_redirect   Optional. Redirect to the new URL.
  * @return string|void The string of the URL, if redirect needed.
  */
 function redirect_canonical( $requested_url = null, $do_redirect = true ) {
 	global $wp_rewrite, $is_IIS, $wp_query, $wpdb, $wp;
 
-	if ( isset( $_SERVER['REQUEST_METHOD'] ) && ! in_array( strtoupper( $_SERVER['REQUEST_METHOD'] ), array( 'GET', 'HEAD' ) ) ) {
+	if ( isset( $_SERVER['REQUEST_METHOD'] ) && ! in_array( strtoupper( $_SERVER['REQUEST_METHOD'] ), array( 'GET', 'HEAD' ), true ) ) {
 		return;
 	}
 
 	// If we're not in wp-admin and the post has been published and preview nonce
-	// is non-existent or invalid then no need for preview in query
-	if ( is_preview() && get_query_var( 'p' ) && 'publish' == get_post_status( get_query_var( 'p' ) ) ) {
+	// is non-existent or invalid then no need for preview in query.
+	if ( is_preview() && get_query_var( 'p' ) && 'publish' === get_post_status( get_query_var( 'p' ) ) ) {
 		if ( ! isset( $_GET['preview_id'] )
 			|| ! isset( $_GET['preview_nonce'] )
-			|| ! wp_verify_nonce( $_GET['preview_nonce'], 'post_preview_' . (int) $_GET['preview_id'] ) ) {
+			|| ! wp_verify_nonce( $_GET['preview_nonce'], 'post_preview_' . (int) $_GET['preview_id'] )
+		) {
 			$wp_query->is_preview = false;
 		}
 	}
 
-	if ( is_trackback() || is_search() || is_admin() || is_preview() || is_robots() || ( $is_IIS && ! iis7_supports_permalinks() ) ) {
+	if ( is_admin() || is_search() || is_preview() || is_trackback() || is_favicon()
+		|| ( $is_IIS && ! iis7_supports_permalinks() )
+	) {
 		return;
 	}
 
 	if ( ! $requested_url && isset( $_SERVER['HTTP_HOST'] ) ) {
-		// build the URL in the address bar
+		// Build the URL in the address bar.
 		$requested_url  = is_ssl() ? 'https://' : 'http://';
 		$requested_url .= $_SERVER['HTTP_HOST'];
 		$requested_url .= $_SERVER['REQUEST_URI'];
 	}
 
-	$original = @parse_url( $requested_url );
+	$original = parse_url( $requested_url );
 	if ( false === $original ) {
 		return;
 	}
@@ -75,7 +78,7 @@
 	$redirect     = $original;
 	$redirect_url = false;
 
-	// Notice fixing
+	// Notice fixing.
 	if ( ! isset( $redirect['path'] ) ) {
 		$redirect['path'] = '';
 	}
@@ -83,84 +86,144 @@
 		$redirect['query'] = '';
 	}
 
-	// If the original URL ended with non-breaking spaces, they were almost
-	// certainly inserted by accident. Let's remove them, so the reader doesn't
-	// see a 404 error with no obvious cause.
+	/*
+	 * If the original URL ended with non-breaking spaces, they were almost
+	 * certainly inserted by accident. Let's remove them, so the reader doesn't
+	 * see a 404 error with no obvious cause.
+	 */
 	$redirect['path'] = preg_replace( '|(%C2%A0)+$|i', '', $redirect['path'] );
 
-	// It's not a preview, so remove it from URL
+	// It's not a preview, so remove it from URL.
 	if ( get_query_var( 'preview' ) ) {
 		$redirect['query'] = remove_query_arg( 'preview', $redirect['query'] );
 	}
 
-	if ( is_feed() && ( $id = get_query_var( 'p' ) ) ) {
-		if ( $redirect_url = get_post_comments_feed_link( $id, get_query_var( 'feed' ) ) ) {
-			$redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type', 'feed' ), $redirect_url );
-			$redirect['path']  = parse_url( $redirect_url, PHP_URL_PATH );
+	$post_id = get_query_var( 'p' );
+
+	if ( is_feed() && $post_id ) {
+		$redirect_url = get_post_comments_feed_link( $post_id, get_query_var( 'feed' ) );
+
+		if ( $redirect_url ) {
+			$redirect['query'] = _remove_qs_args_if_not_in_url(
+				$redirect['query'],
+				array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type', 'feed' ),
+				$redirect_url
+			);
+
+			$redirect['path'] = parse_url( $redirect_url, PHP_URL_PATH );
 		}
 	}
 
-	if ( is_singular() && 1 > $wp_query->post_count && ( $id = get_query_var( 'p' ) ) ) {
+	if ( is_singular() && $wp_query->post_count < 1 && $post_id ) {
 
-		$vars = $wpdb->get_results( $wpdb->prepare( "SELECT post_type, post_parent FROM $wpdb->posts WHERE ID = %d", $id ) );
+		$vars = $wpdb->get_results( $wpdb->prepare( "SELECT post_type, post_parent FROM $wpdb->posts WHERE ID = %d", $post_id ) );
 
-		if ( isset( $vars[0] ) && $vars = $vars[0] ) {
-			if ( 'revision' == $vars->post_type && $vars->post_parent > 0 ) {
-				$id = $vars->post_parent;
+		if ( ! empty( $vars[0] ) ) {
+			$vars = $vars[0];
+
+			if ( 'revision' === $vars->post_type && $vars->post_parent > 0 ) {
+				$post_id = $vars->post_parent;
 			}
 
-			if ( $redirect_url = get_permalink( $id ) ) {
-				$redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
+			$redirect_url = get_permalink( $post_id );
+
+			if ( $redirect_url ) {
+				$redirect['query'] = _remove_qs_args_if_not_in_url(
+					$redirect['query'],
+					array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ),
+					$redirect_url
+				);
 			}
 		}
 	}
 
-	// These tests give us a WP-generated permalink
+	// These tests give us a WP-generated permalink.
 	if ( is_404() ) {
 
-		// Redirect ?page_id, ?p=, ?attachment_id= to their respective url's
-		$id = max( get_query_var( 'p' ), get_query_var( 'page_id' ), get_query_var( 'attachment_id' ) );
-		if ( $id && $redirect_post = get_post( $id ) ) {
+		// Redirect ?page_id, ?p=, ?attachment_id= to their respective URLs.
+		$post_id = max( get_query_var( 'p' ), get_query_var( 'page_id' ), get_query_var( 'attachment_id' ) );
+
+		$redirect_post = $post_id ? get_post( $post_id ) : false;
+
+		if ( $redirect_post ) {
 			$post_type_obj = get_post_type_object( $redirect_post->post_type );
-			if ( $post_type_obj->public && 'auto-draft' != $redirect_post->post_status ) {
-				$redirect_url      = get_permalink( $redirect_post );
-				$redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
+
+			if ( $post_type_obj->public && 'auto-draft' !== $redirect_post->post_status ) {
+				$redirect_url = get_permalink( $redirect_post );
+
+				$redirect['query'] = _remove_qs_args_if_not_in_url(
+					$redirect['query'],
+					array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ),
+					$redirect_url
+				);
 			}
 		}
 
-		if ( get_query_var( 'day' ) && get_query_var( 'monthnum' ) && get_query_var( 'year' ) ) {
-			$year  = get_query_var( 'year' );
-			$month = get_query_var( 'monthnum' );
-			$day   = get_query_var( 'day' );
-			$date  = sprintf( '%04d-%02d-%02d', $year, $month, $day );
+		$year  = get_query_var( 'year' );
+		$month = get_query_var( 'monthnum' );
+		$day   = get_query_var( 'day' );
+
+		if ( $year && $month && $day ) {
+			$date = sprintf( '%04d-%02d-%02d', $year, $month, $day );
+
 			if ( ! wp_checkdate( $month, $day, $year, $date ) ) {
-				$redirect_url      = get_month_link( $year, $month );
-				$redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'year', 'monthnum', 'day' ), $redirect_url );
+				$redirect_url = get_month_link( $year, $month );
+
+				$redirect['query'] = _remove_qs_args_if_not_in_url(
+					$redirect['query'],
+					array( 'year', 'monthnum', 'day' ),
+					$redirect_url
+				);
 			}
-		} elseif ( get_query_var( 'monthnum' ) && get_query_var( 'year' ) && 12 < get_query_var( 'monthnum' ) ) {
-			$redirect_url      = get_year_link( get_query_var( 'year' ) );
-			$redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'year', 'monthnum' ), $redirect_url );
+		} elseif ( $year && $month && $month > 12 ) {
+			$redirect_url = get_year_link( $year );
+
+			$redirect['query'] = _remove_qs_args_if_not_in_url(
+				$redirect['query'],
+				array( 'year', 'monthnum' ),
+				$redirect_url
+			);
+		}
+
+		// Strip off non-existing <!--nextpage--> links from single posts or pages.
+		if ( get_query_var( 'page' ) ) {
+			$post_id = 0;
+
+			if ( $wp_query->queried_object instanceof WP_Post ) {
+				$post_id = $wp_query->queried_object->ID;
+			} elseif ( $wp_query->post ) {
+				$post_id = $wp_query->post->ID;
+			}
+
+			if ( $post_id ) {
+				$redirect_url = get_permalink( $post_id );
+
+				$redirect['path']  = rtrim( $redirect['path'], (int) get_query_var( 'page' ) . '/' );
+				$redirect['query'] = remove_query_arg( 'page', $redirect['query'] );
+			}
 		}
 
 		if ( ! $redirect_url ) {
-			if ( $redirect_url = redirect_guess_404_permalink() ) {
-				$redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'page', 'feed', 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
+			$redirect_url = redirect_guess_404_permalink();
+
+			if ( $redirect_url ) {
+				$redirect['query'] = _remove_qs_args_if_not_in_url(
+					$redirect['query'],
+					array( 'page', 'feed', 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ),
+					$redirect_url
+				);
 			}
 		}
+	} elseif ( is_object( $wp_rewrite ) && $wp_rewrite->using_permalinks() ) {
 
-		if ( get_query_var( 'page' ) && $wp_query->post &&
-			false !== strpos( $wp_query->post->post_content, '<!--nextpage-->' ) ) {
-			$redirect['path']  = rtrim( $redirect['path'], (int) get_query_var( 'page' ) . '/' );
-			$redirect['query'] = remove_query_arg( 'page', $redirect['query'] );
-			$redirect_url      = get_permalink( $wp_query->post->ID );
-		}
-	} elseif ( is_object( $wp_rewrite ) && $wp_rewrite->using_permalinks() ) {
-		// rewriting of old ?p=X, ?m=2004, ?m=200401, ?m=20040101
-		if ( is_attachment() &&
-			! array_diff( array_keys( $wp->query_vars ), array( 'attachment', 'attachment_id' ) ) &&
-			! $redirect_url ) {
+		// Rewriting of old ?p=X, ?m=2004, ?m=200401, ?m=20040101.
+		if ( is_attachment()
+			&& ! array_diff( array_keys( $wp->query_vars ), array( 'attachment', 'attachment_id' ) )
+			&& ! $redirect_url
+		) {
 			if ( ! empty( $_GET['attachment_id'] ) ) {
 				$redirect_url = get_attachment_link( get_query_var( 'attachment_id' ) );
+
 				if ( $redirect_url ) {
 					$redirect['query'] = remove_query_arg( 'attachment_id', $redirect['query'] );
 				}
@@ -168,200 +231,290 @@
 				$redirect_url = get_attachment_link();
 			}
 		} elseif ( is_single() && ! empty( $_GET['p'] ) && ! $redirect_url ) {
-			if ( $redirect_url = get_permalink( get_query_var( 'p' ) ) ) {
+			$redirect_url = get_permalink( get_query_var( 'p' ) );
+
+			if ( $redirect_url ) {
 				$redirect['query'] = remove_query_arg( array( 'p', 'post_type' ), $redirect['query'] );
 			}
 		} elseif ( is_single() && ! empty( $_GET['name'] ) && ! $redirect_url ) {
-			if ( $redirect_url = get_permalink( $wp_query->get_queried_object_id() ) ) {
+			$redirect_url = get_permalink( $wp_query->get_queried_object_id() );
+
+			if ( $redirect_url ) {
 				$redirect['query'] = remove_query_arg( 'name', $redirect['query'] );
 			}
 		} elseif ( is_page() && ! empty( $_GET['page_id'] ) && ! $redirect_url ) {
-			if ( $redirect_url = get_permalink( get_query_var( 'page_id' ) ) ) {
+			$redirect_url = get_permalink( get_query_var( 'page_id' ) );
+
+			if ( $redirect_url ) {
 				$redirect['query'] = remove_query_arg( 'page_id', $redirect['query'] );
 			}
-		} elseif ( is_page() && ! is_feed() && 'page' == get_option( 'show_on_front' ) && get_queried_object_id() == get_option( 'page_on_front' ) && ! $redirect_url ) {
+		} elseif ( is_page() && ! is_feed() && ! $redirect_url
+			&& 'page' === get_option( 'show_on_front' ) && get_queried_object_id() === (int) get_option( 'page_on_front' )
+		) {
 			$redirect_url = home_url( '/' );
-		} elseif ( is_home() && ! empty( $_GET['page_id'] ) && 'page' == get_option( 'show_on_front' ) && get_query_var( 'page_id' ) == get_option( 'page_for_posts' ) && ! $redirect_url ) {
-			if ( $redirect_url = get_permalink( get_option( 'page_for_posts' ) ) ) {
+		} elseif ( is_home() && ! empty( $_GET['page_id'] ) && ! $redirect_url
+			&& 'page' === get_option( 'show_on_front' ) && get_query_var( 'page_id' ) === (int) get_option( 'page_for_posts' )
+		) {
+			$redirect_url = get_permalink( get_option( 'page_for_posts' ) );
+
+			if ( $redirect_url ) {
 				$redirect['query'] = remove_query_arg( 'page_id', $redirect['query'] );
 			}
 		} elseif ( ! empty( $_GET['m'] ) && ( is_year() || is_month() || is_day() ) ) {
 			$m = get_query_var( 'm' );
+
 			switch ( strlen( $m ) ) {
-				case 4: // Yearly
+				case 4: // Yearly.
 					$redirect_url = get_year_link( $m );
 					break;
-				case 6: // Monthly
+				case 6: // Monthly.
 					$redirect_url = get_month_link( substr( $m, 0, 4 ), substr( $m, 4, 2 ) );
 					break;
-				case 8: // Daily
+				case 8: // Daily.
 					$redirect_url = get_day_link( substr( $m, 0, 4 ), substr( $m, 4, 2 ), substr( $m, 6, 2 ) );
 					break;
 			}
+
 			if ( $redirect_url ) {
 				$redirect['query'] = remove_query_arg( 'm', $redirect['query'] );
 			}
-			// now moving on to non ?m=X year/month/day links
-		} elseif ( is_day() && get_query_var( 'year' ) && get_query_var( 'monthnum' ) && ! empty( $_GET['day'] ) ) {
-			if ( $redirect_url = get_day_link( get_query_var( 'year' ), get_query_var( 'monthnum' ), get_query_var( 'day' ) ) ) {
-				$redirect['query'] = remove_query_arg( array( 'year', 'monthnum', 'day' ), $redirect['query'] );
-			}
-		} elseif ( is_month() && get_query_var( 'year' ) && ! empty( $_GET['monthnum'] ) ) {
-			if ( $redirect_url = get_month_link( get_query_var( 'year' ), get_query_var( 'monthnum' ) ) ) {
-				$redirect['query'] = remove_query_arg( array( 'year', 'monthnum' ), $redirect['query'] );
-			}
-		} elseif ( is_year() && ! empty( $_GET['year'] ) ) {
-			if ( $redirect_url = get_year_link( get_query_var( 'year' ) ) ) {
-				$redirect['query'] = remove_query_arg( 'year', $redirect['query'] );
+			// Now moving on to non ?m=X year/month/day links.
+		} elseif ( is_date() ) {
+			$year  = get_query_var( 'year' );
+			$month = get_query_var( 'monthnum' );
+			$day   = get_query_var( 'day' );
+
+			if ( is_day() && $year && $month && ! empty( $_GET['day'] ) ) {
+				$redirect_url = get_day_link( $year, $month, $day );
+
+				if ( $redirect_url ) {
+					$redirect['query'] = remove_query_arg( array( 'year', 'monthnum', 'day' ), $redirect['query'] );
+				}
+			} elseif ( is_month() && $year && ! empty( $_GET['monthnum'] ) ) {
+				$redirect_url = get_month_link( $year, $month );
+
+				if ( $redirect_url ) {
+					$redirect['query'] = remove_query_arg( array( 'year', 'monthnum' ), $redirect['query'] );
+				}
+			} elseif ( is_year() && ! empty( $_GET['year'] ) ) {
+				$redirect_url = get_year_link( $year );
+
+				if ( $redirect_url ) {
+					$redirect['query'] = remove_query_arg( 'year', $redirect['query'] );
+				}
 			}
 		} elseif ( is_author() && ! empty( $_GET['author'] ) && preg_match( '|^[0-9]+$|', $_GET['author'] ) ) {
 			$author = get_userdata( get_query_var( 'author' ) );
-			if ( ( false !== $author ) && $wpdb->get_var( $wpdb->prepare( "SELECT ID FROM $wpdb->posts WHERE $wpdb->posts.post_author = %d AND $wpdb->posts.post_status = 'publish' LIMIT 1", $author->ID ) ) ) {
-				if ( $redirect_url = get_author_posts_url( $author->ID, $author->user_nicename ) ) {
+
+			if ( false !== $author
+				&& $wpdb->get_var( $wpdb->prepare( "SELECT ID FROM $wpdb->posts WHERE $wpdb->posts.post_author = %d AND $wpdb->posts.post_status = 'publish' LIMIT 1", $author->ID ) )
+			) {
+				$redirect_url = get_author_posts_url( $author->ID, $author->user_nicename );
+
+				if ( $redirect_url ) {
 					$redirect['query'] = remove_query_arg( 'author', $redirect['query'] );
 				}
 			}
-		} elseif ( is_category() || is_tag() || is_tax() ) { // Terms (Tags/categories)
+		} elseif ( is_category() || is_tag() || is_tax() ) { // Terms (tags/categories).
+			$term_count = 0;
 
-			$term_count = 0;
 			foreach ( $wp_query->tax_query->queried_terms as $tax_query ) {
 				$term_count += count( $tax_query['terms'] );
 			}
 
 			$obj = $wp_query->get_queried_object();
-			if ( $term_count <= 1 && ! empty( $obj->term_id ) && ( $tax_url = get_term_link( (int) $obj->term_id, $obj->taxonomy ) ) && ! is_wp_error( $tax_url ) ) {
-				if ( ! empty( $redirect['query'] ) ) {
-					// Strip taxonomy query vars off the url.
-					$qv_remove = array( 'term', 'taxonomy' );
-					if ( is_category() ) {
-						$qv_remove[] = 'category_name';
-						$qv_remove[] = 'cat';
-					} elseif ( is_tag() ) {
-						$qv_remove[] = 'tag';
-						$qv_remove[] = 'tag_id';
-					} else { // Custom taxonomies will have a custom query var, remove those too:
-						$tax_obj = get_taxonomy( $obj->taxonomy );
-						if ( false !== $tax_obj->query_var ) {
-							$qv_remove[] = $tax_obj->query_var;
+
+			if ( $term_count <= 1 && ! empty( $obj->term_id ) ) {
+				$tax_url = get_term_link( (int) $obj->term_id, $obj->taxonomy );
+
+				if ( $tax_url && ! is_wp_error( $tax_url ) ) {
+					if ( ! empty( $redirect['query'] ) ) {
+						// Strip taxonomy query vars off the URL.
+						$qv_remove = array( 'term', 'taxonomy' );
+
+						if ( is_category() ) {
+							$qv_remove[] = 'category_name';
+							$qv_remove[] = 'cat';
+						} elseif ( is_tag() ) {
+							$qv_remove[] = 'tag';
+							$qv_remove[] = 'tag_id';
+						} else {
+							// Custom taxonomies will have a custom query var, remove those too.
+							$tax_obj = get_taxonomy( $obj->taxonomy );
+							if ( false !== $tax_obj->query_var ) {
+								$qv_remove[] = $tax_obj->query_var;
+							}
 						}
-					}
 
-					$rewrite_vars = array_diff( array_keys( $wp_query->query ), array_keys( $_GET ) );
+						$rewrite_vars = array_diff( array_keys( $wp_query->query ), array_keys( $_GET ) );
 
-					if ( ! array_diff( $rewrite_vars, array_keys( $_GET ) ) ) { // Check to see if all the Query vars are coming from the rewrite, none are set via $_GET
-						$redirect['query'] = remove_query_arg( $qv_remove, $redirect['query'] ); //Remove all of the per-tax qv's
+						// Check to see if all the query vars are coming from the rewrite, none are set via $_GET.
+						if ( ! array_diff( $rewrite_vars, array_keys( $_GET ) ) ) {
+							// Remove all of the per-tax query vars.
+							$redirect['query'] = remove_query_arg( $qv_remove, $redirect['query'] );
+
+							// Create the destination URL for this taxonomy.
+							$tax_url = parse_url( $tax_url );
 
-						// Create the destination url for this taxonomy
-						$tax_url = parse_url( $tax_url );
-						if ( ! empty( $tax_url['query'] ) ) { // Taxonomy accessible via ?taxonomy=..&term=.. or any custom qv..
-							parse_str( $tax_url['query'], $query_vars );
-							$redirect['query'] = add_query_arg( $query_vars, $redirect['query'] );
-						} else { // Taxonomy is accessible via a "pretty-URL"
-							$redirect['path'] = $tax_url['path'];
-						}
-					} else { // Some query vars are set via $_GET. Unset those from $_GET that exist via the rewrite
-						foreach ( $qv_remove as $_qv ) {
-							if ( isset( $rewrite_vars[ $_qv ] ) ) {
-								$redirect['query'] = remove_query_arg( $_qv, $redirect['query'] );
+							if ( ! empty( $tax_url['query'] ) ) {
+								// Taxonomy accessible via ?taxonomy=...&term=... or any custom query var.
+								parse_str( $tax_url['query'], $query_vars );
+								$redirect['query'] = add_query_arg( $query_vars, $redirect['query'] );
+							} else {
+								// Taxonomy is accessible via a "pretty URL".
+								$redirect['path'] = $tax_url['path'];
+							}
+						} else {
+							// Some query vars are set via $_GET. Unset those from $_GET that exist via the rewrite.
+							foreach ( $qv_remove as $_qv ) {
+								if ( isset( $rewrite_vars[ $_qv ] ) ) {
+									$redirect['query'] = remove_query_arg( $_qv, $redirect['query'] );
+								}
 							}
 						}
 					}
 				}
 			}
-		} elseif ( is_single() && strpos( $wp_rewrite->permalink_structure, '%category%' ) !== false && $cat = get_query_var( 'category_name' ) ) {
-			$category = get_category_by_path( $cat );
-			if ( ( ! $category || is_wp_error( $category ) ) || ! has_term( $category->term_id, 'category', $wp_query->get_queried_object_id() ) ) {
-				$redirect_url = get_permalink( $wp_query->get_queried_object_id() );
+		} elseif ( is_single() && strpos( $wp_rewrite->permalink_structure, '%category%' ) !== false ) {
+			$category_name = get_query_var( 'category_name' );
+
+			if ( $category_name ) {
+				$category = get_category_by_path( $category_name );
+
+				if ( ! $category || is_wp_error( $category )
+					|| ! has_term( $category->term_id, 'category', $wp_query->get_queried_object_id() )
+				) {
+					$redirect_url = get_permalink( $wp_query->get_queried_object_id() );
+				}
 			}
 		}
 
-			// Post Paging
+		// Post paging.
 		if ( is_singular() && get_query_var( 'page' ) ) {
+			$page = get_query_var( 'page' );
+
 			if ( ! $redirect_url ) {
 				$redirect_url = get_permalink( get_queried_object_id() );
 			}
 
-			$page = get_query_var( 'page' );
 			if ( $page > 1 ) {
+				$redirect_url = trailingslashit( $redirect_url );
+
 				if ( is_front_page() ) {
-					$redirect_url = trailingslashit( $redirect_url ) . user_trailingslashit( "$wp_rewrite->pagination_base/$page", 'paged' );
+					$redirect_url .= user_trailingslashit( "$wp_rewrite->pagination_base/$page", 'paged' );
 				} else {
-					$redirect_url = trailingslashit( $redirect_url ) . user_trailingslashit( $page, 'single_paged' );
+					$redirect_url .= user_trailingslashit( $page, 'single_paged' );
 				}
 			}
-				$redirect['query'] = remove_query_arg( 'page', $redirect['query'] );
+
+			$redirect['query'] = remove_query_arg( 'page', $redirect['query'] );
 		}
 
-			// paging and feeds
-		if ( get_query_var( 'paged' ) || is_feed() || get_query_var( 'cpage' ) ) {
-			while ( preg_match( "#/$wp_rewrite->pagination_base/?[0-9]+?(/+)?$#", $redirect['path'] ) || preg_match( '#/(comments/?)?(feed|rss|rdf|atom|rss2)(/+)?$#', $redirect['path'] ) || preg_match( "#/{$wp_rewrite->comments_pagination_base}-[0-9]+(/+)?$#", $redirect['path'] ) ) {
-				// Strip off paging and feed
-				$redirect['path'] = preg_replace( "#/$wp_rewrite->pagination_base/?[0-9]+?(/+)?$#", '/', $redirect['path'] ); // strip off any existing paging
-				$redirect['path'] = preg_replace( '#/(comments/?)?(feed|rss2?|rdf|atom)(/+|$)#', '/', $redirect['path'] ); // strip off feed endings
-				$redirect['path'] = preg_replace( "#/{$wp_rewrite->comments_pagination_base}-[0-9]+?(/+)?$#", '/', $redirect['path'] ); // strip off any existing comment paging
+		if ( get_query_var( 'sitemap' ) ) {
+			$redirect_url      = get_sitemap_url( get_query_var( 'sitemap' ), get_query_var( 'sitemap-subtype' ), get_query_var( 'paged' ) );
+			$redirect['query'] = remove_query_arg( array( 'sitemap', 'sitemap-subtype', 'paged' ), $redirect['query'] );
+		} elseif ( get_query_var( 'paged' ) || is_feed() || get_query_var( 'cpage' ) ) {
+			// Paging and feeds.
+			$paged = get_query_var( 'paged' );
+			$feed  = get_query_var( 'feed' );
+			$cpage = get_query_var( 'cpage' );
+
+			while ( preg_match( "#/$wp_rewrite->pagination_base/?[0-9]+?(/+)?$#", $redirect['path'] )
+				|| preg_match( '#/(comments/?)?(feed|rss2?|rdf|atom)(/+)?$#', $redirect['path'] )
+				|| preg_match( "#/{$wp_rewrite->comments_pagination_base}-[0-9]+(/+)?$#", $redirect['path'] )
+			) {
+				// Strip off any existing paging.
+				$redirect['path'] = preg_replace( "#/$wp_rewrite->pagination_base/?[0-9]+?(/+)?$#", '/', $redirect['path'] );
+				// Strip off feed endings.
+				$redirect['path'] = preg_replace( '#/(comments/?)?(feed|rss2?|rdf|atom)(/+|$)#', '/', $redirect['path'] );
+				// Strip off any existing comment paging.
+				$redirect['path'] = preg_replace( "#/{$wp_rewrite->comments_pagination_base}-[0-9]+?(/+)?$#", '/', $redirect['path'] );
 			}
 
-			$addl_path = '';
-			if ( is_feed() && in_array( get_query_var( 'feed' ), $wp_rewrite->feeds ) ) {
+			$addl_path    = '';
+			$default_feed = get_default_feed();
+
+			if ( is_feed() && in_array( $feed, $wp_rewrite->feeds, true ) ) {
 				$addl_path = ! empty( $addl_path ) ? trailingslashit( $addl_path ) : '';
+
 				if ( ! is_singular() && get_query_var( 'withcomments' ) ) {
 					$addl_path .= 'comments/';
 				}
-				if ( ( 'rss' == get_default_feed() && 'feed' == get_query_var( 'feed' ) ) || 'rss' == get_query_var( 'feed' ) ) {
-					$addl_path .= user_trailingslashit( 'feed/' . ( ( get_default_feed() == 'rss2' ) ? '' : 'rss2' ), 'feed' );
+
+				if ( ( 'rss' === $default_feed && 'feed' === $feed ) || 'rss' === $feed ) {
+					$format = ( 'rss2' === $default_feed ) ? '' : 'rss2';
 				} else {
-					$addl_path .= user_trailingslashit( 'feed/' . ( ( get_default_feed() == get_query_var( 'feed' ) || 'feed' == get_query_var( 'feed' ) ) ? '' : get_query_var( 'feed' ) ), 'feed' );
+					$format = ( $default_feed === $feed || 'feed' === $feed ) ? '' : $feed;
 				}
+
+				$addl_path .= user_trailingslashit( 'feed/' . $format, 'feed' );
+
 				$redirect['query'] = remove_query_arg( 'feed', $redirect['query'] );
-			} elseif ( is_feed() && 'old' == get_query_var( 'feed' ) ) {
+			} elseif ( is_feed() && 'old' === $feed ) {
 				$old_feed_files = array(
 					'wp-atom.php'         => 'atom',
 					'wp-commentsrss2.php' => 'comments_rss2',
-					'wp-feed.php'         => get_default_feed(),
+					'wp-feed.php'         => $default_feed,
 					'wp-rdf.php'          => 'rdf',
 					'wp-rss.php'          => 'rss2',
 					'wp-rss2.php'         => 'rss2',
 				);
+
 				if ( isset( $old_feed_files[ basename( $redirect['path'] ) ] ) ) {
 					$redirect_url = get_feed_link( $old_feed_files[ basename( $redirect['path'] ) ] );
+
 					wp_redirect( $redirect_url, 301 );
 					die();
 				}
 			}
 
-			if ( get_query_var( 'paged' ) > 0 ) {
-				$paged             = get_query_var( 'paged' );
+			if ( $paged > 0 ) {
 				$redirect['query'] = remove_query_arg( 'paged', $redirect['query'] );
+
 				if ( ! is_feed() ) {
-					if ( $paged > 1 && ! is_single() ) {
-						$addl_path = ( ! empty( $addl_path ) ? trailingslashit( $addl_path ) : '' ) . user_trailingslashit( "$wp_rewrite->pagination_base/$paged", 'paged' );
-					} elseif ( ! is_single() ) {
+					if ( ! is_single() ) {
 						$addl_path = ! empty( $addl_path ) ? trailingslashit( $addl_path ) : '';
+
+						if ( $paged > 1 ) {
+							$addl_path .= user_trailingslashit( "$wp_rewrite->pagination_base/$paged", 'paged' );
+						}
 					}
 				} elseif ( $paged > 1 ) {
 					$redirect['query'] = add_query_arg( 'paged', $paged, $redirect['query'] );
 				}
 			}
 
-			if ( get_option( 'page_comments' ) && (
-			( 'newest' == get_option( 'default_comments_page' ) && get_query_var( 'cpage' ) > 0 ) ||
-			( 'newest' != get_option( 'default_comments_page' ) && get_query_var( 'cpage' ) > 1 )
-			) ) {
-				$addl_path         = ( ! empty( $addl_path ) ? trailingslashit( $addl_path ) : '' ) . user_trailingslashit( $wp_rewrite->comments_pagination_base . '-' . get_query_var( 'cpage' ), 'commentpaged' );
+			$default_comments_page = get_option( 'default_comments_page' );
+
+			if ( get_option( 'page_comments' )
+				&& ( 'newest' === $default_comments_page && $cpage > 0
+					|| 'newest' !== $default_comments_page && $cpage > 1 )
+			) {
+				$addl_path  = ( ! empty( $addl_path ) ? trailingslashit( $addl_path ) : '' );
+				$addl_path .= user_trailingslashit( $wp_rewrite->comments_pagination_base . '-' . $cpage, 'commentpaged' );
+
 				$redirect['query'] = remove_query_arg( 'cpage', $redirect['query'] );
 			}
 
-			$redirect['path'] = user_trailingslashit( preg_replace( '|/' . preg_quote( $wp_rewrite->index, '|' ) . '/?$|', '/', $redirect['path'] ) ); // strip off trailing /index.php/
-			if ( ! empty( $addl_path ) && $wp_rewrite->using_index_permalinks() && strpos( $redirect['path'], '/' . $wp_rewrite->index . '/' ) === false ) {
+			// Strip off trailing /index.php/.
+			$redirect['path'] = preg_replace( '|/' . preg_quote( $wp_rewrite->index, '|' ) . '/?$|', '/', $redirect['path'] );
+			$redirect['path'] = user_trailingslashit( $redirect['path'] );
+
+			if ( ! empty( $addl_path )
+				&& $wp_rewrite->using_index_permalinks()
+				&& strpos( $redirect['path'], '/' . $wp_rewrite->index . '/' ) === false
+			) {
 				$redirect['path'] = trailingslashit( $redirect['path'] ) . $wp_rewrite->index . '/';
 			}
+
 			if ( ! empty( $addl_path ) ) {
 				$redirect['path'] = trailingslashit( $redirect['path'] ) . $addl_path;
 			}
+
 			$redirect_url = $redirect['scheme'] . '://' . $redirect['host'] . $redirect['path'];
 		}
 
-		if ( 'wp-register.php' == basename( $redirect['path'] ) ) {
+		if ( 'wp-register.php' === basename( $redirect['path'] ) ) {
 			if ( is_multisite() ) {
 				/** This filter is documented in wp-login.php */
 				$redirect_url = apply_filters( 'wp_signup_location', network_site_url( 'wp-signup.php' ) );
@@ -374,11 +527,12 @@
 		}
 	}
 
-	// tack on any additional query vars
 	$redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
+
+	// Tack on any additional query vars.
 	if ( $redirect_url && ! empty( $redirect['query'] ) ) {
 		parse_str( $redirect['query'], $_parsed_query );
-		$redirect = @parse_url( $redirect_url );
+		$redirect = parse_url( $redirect_url );
 
 		if ( ! empty( $_parsed_query['name'] ) && ! empty( $redirect['query'] ) ) {
 			parse_str( $redirect['query'], $_parsed_redirect_query );
@@ -392,30 +546,33 @@
 			rawurlencode_deep( array_keys( $_parsed_query ) ),
 			rawurlencode_deep( array_values( $_parsed_query ) )
 		);
-		$redirect_url  = add_query_arg( $_parsed_query, $redirect_url );
+
+		$redirect_url = add_query_arg( $_parsed_query, $redirect_url );
 	}
 
 	if ( $redirect_url ) {
-		$redirect = @parse_url( $redirect_url );
+		$redirect = parse_url( $redirect_url );
 	}
 
-	// www.example.com vs example.com
-	$user_home = @parse_url( home_url() );
+	// www.example.com vs. example.com
+	$user_home = parse_url( home_url() );
+
 	if ( ! empty( $user_home['host'] ) ) {
 		$redirect['host'] = $user_home['host'];
 	}
+
 	if ( empty( $user_home['path'] ) ) {
 		$user_home['path'] = '/';
 	}
 
-	// Handle ports
+	// Handle ports.
 	if ( ! empty( $user_home['port'] ) ) {
 		$redirect['port'] = $user_home['port'];
 	} else {
 		unset( $redirect['port'] );
 	}
 
-	// trailing /index.php
+	// Trailing /index.php.
 	$redirect['path'] = preg_replace( '|/' . preg_quote( $wp_rewrite->index, '|' ) . '/*?$|', '/', $redirect['path'] );
 
 	$punctuation_pattern = implode(
@@ -424,29 +581,29 @@
 			'preg_quote',
 			array(
 				' ',
-				'%20',  // space
+				'%20',  // Space.
 				'!',
-				'%21',  // exclamation mark
+				'%21',  // Exclamation mark.
 				'"',
-				'%22',  // double quote
+				'%22',  // Double quote.
 				"'",
-				'%27',  // single quote
+				'%27',  // Single quote.
 				'(',
-				'%28',  // opening bracket
+				'%28',  // Opening bracket.
 				')',
-				'%29',  // closing bracket
+				'%29',  // Closing bracket.
 				',',
-				'%2C',  // comma
+				'%2C',  // Comma.
 				'.',
-				'%2E',  // period
+				'%2E',  // Period.
 				';',
-				'%3B',  // semicolon
+				'%3B',  // Semicolon.
 				'{',
-				'%7B',  // opening curly bracket
+				'%7B',  // Opening curly bracket.
 				'}',
-				'%7D',  // closing curly bracket
-				'%E2%80%9C', // opening curly quote
-				'%E2%80%9D', // closing curly quote
+				'%7D',  // Closing curly bracket.
+				'%E2%80%9C', // Opening curly quote.
+				'%E2%80%9D', // Closing curly quote.
 			)
 		)
 	);
@@ -456,26 +613,29 @@
 
 	if ( ! empty( $redirect['query'] ) ) {
 		// Remove trailing spaces and end punctuation from certain terminating query string args.
-		$redirect['query'] = preg_replace( "#((p|page_id|cat|tag)=[^&]*?)($punctuation_pattern)+$#", '$1', $redirect['query'] );
+		$redirect['query'] = preg_replace( "#((^|&)(p|page_id|cat|tag)=[^&]*?)($punctuation_pattern)+$#", '$1', $redirect['query'] );
 
-		// Clean up empty query strings
+		// Clean up empty query strings.
 		$redirect['query'] = trim( preg_replace( '#(^|&)(p|page_id|cat|tag)=?(&|$)#', '&', $redirect['query'] ), '&' );
 
-		// Redirect obsolete feeds
+		// Redirect obsolete feeds.
 		$redirect['query'] = preg_replace( '#(^|&)feed=rss(&|$)#', '$1feed=rss2$2', $redirect['query'] );
 
-		// Remove redundant leading ampersands
+		// Remove redundant leading ampersands.
 		$redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
 	}
 
-	// strip /index.php/ when we're not using PATHINFO permalinks
+	// Strip /index.php/ when we're not using PATHINFO permalinks.
 	if ( ! $wp_rewrite->using_index_permalinks() ) {
 		$redirect['path'] = str_replace( '/' . $wp_rewrite->index . '/', '/', $redirect['path'] );
 	}
 
-	// trailing slashes
-	if ( is_object( $wp_rewrite ) && $wp_rewrite->using_permalinks() && ! is_404() && ( ! is_front_page() || ( is_front_page() && ( get_query_var( 'paged' ) > 1 ) ) ) ) {
+	// Trailing slashes.
+	if ( is_object( $wp_rewrite ) && $wp_rewrite->using_permalinks()
+		&& ! is_404() && ( ! is_front_page() || is_front_page() && get_query_var( 'paged' ) > 1 )
+	) {
 		$user_ts_type = '';
+
 		if ( get_query_var( 'paged' ) > 0 ) {
 			$user_ts_type = 'paged';
 		} else {
@@ -487,25 +647,38 @@
 				}
 			}
 		}
+
 		$redirect['path'] = user_trailingslashit( $redirect['path'], $user_ts_type );
 	} elseif ( is_front_page() ) {
 		$redirect['path'] = trailingslashit( $redirect['path'] );
 	}
 
-	// Strip multiple slashes out of the URL
+	// Remove trailing slash for robots.txt or sitemap requests.
+	if ( is_robots()
+		|| ! empty( get_query_var( 'sitemap' ) ) || ! empty( get_query_var( 'sitemap-stylesheet' ) )
+	) {
+		$redirect['path'] = untrailingslashit( $redirect['path'] );
+	}
+
+	// Strip multiple slashes out of the URL.
 	if ( strpos( $redirect['path'], '//' ) > -1 ) {
 		$redirect['path'] = preg_replace( '|/+|', '/', $redirect['path'] );
 	}
 
-	// Always trailing slash the Front Page URL
-	if ( trailingslashit( $redirect['path'] ) == trailingslashit( $user_home['path'] ) ) {
+	// Always trailing slash the Front Page URL.
+	if ( trailingslashit( $redirect['path'] ) === trailingslashit( $user_home['path'] ) ) {
 		$redirect['path'] = trailingslashit( $redirect['path'] );
 	}
 
-	// Ignore differences in host capitalization, as this can lead to infinite redirects
-	// Only redirect no-www <=> yes-www
-	if ( strtolower( $original['host'] ) == strtolower( $redirect['host'] ) ||
-		( strtolower( $original['host'] ) != 'www.' . strtolower( $redirect['host'] ) && 'www.' . strtolower( $original['host'] ) != strtolower( $redirect['host'] ) ) ) {
+	$original_host_low = strtolower( $original['host'] );
+	$redirect_host_low = strtolower( $redirect['host'] );
+
+	// Ignore differences in host capitalization, as this can lead to infinite redirects.
+	// Only redirect no-www <=> yes-www.
+	if ( $original_host_low === $redirect_host_low
+		|| ( 'www.' . $original_host_low !== $redirect_host_low
+			&& 'www.' . $redirect_host_low !== $original_host_low )
+	) {
 		$redirect['host'] = $original['host'];
 	}
 
@@ -531,16 +704,19 @@
 
 	if ( $compare_original !== $compare_redirect ) {
 		$redirect_url = $redirect['scheme'] . '://' . $redirect['host'];
+
 		if ( ! empty( $redirect['port'] ) ) {
 			$redirect_url .= ':' . $redirect['port'];
 		}
+
 		$redirect_url .= $redirect['path'];
+
 		if ( ! empty( $redirect['query'] ) ) {
 			$redirect_url .= '?' . $redirect['query'];
 		}
 	}
 
-	if ( ! $redirect_url || $redirect_url == $requested_url ) {
+	if ( ! $redirect_url || $redirect_url === $requested_url ) {
 		return;
 	}
 
@@ -560,6 +736,7 @@
 				return strtolower( $matches[0] );
 			}
 		}
+
 		$requested_url = preg_replace_callback( '|%[a-fA-F0-9][a-fA-F0-9]|', 'lowercase_octets', $requested_url );
 	}
 
@@ -575,18 +752,18 @@
 	 */
 	$redirect_url = apply_filters( 'redirect_canonical', $redirect_url, $requested_url );
 
-	// yes, again -- in case the filter aborted the request
-	if ( ! $redirect_url || strip_fragment_from_url( $redirect_url ) == strip_fragment_from_url( $requested_url ) ) {
+	// Yes, again -- in case the filter aborted the request.
+	if ( ! $redirect_url || strip_fragment_from_url( $redirect_url ) === strip_fragment_from_url( $requested_url ) ) {
 		return;
 	}
 
 	if ( $do_redirect ) {
-		// protect against chained redirects
+		// Protect against chained redirects.
 		if ( ! redirect_canonical( $redirect_url, false ) ) {
 			wp_redirect( $redirect_url, 301 );
-			exit();
+			exit;
 		} else {
-			// Debug
+			// Debug.
 			// die("1: $redirect_url<br />2: " . redirect_canonical( $redirect_url, false ) );
 			return;
 		}
@@ -603,14 +780,16 @@
  * @access private
  *
  * @param string $query_string
- * @param array $args_to_check
+ * @param array  $args_to_check
  * @param string $url
  * @return string The altered query string
  */
 function _remove_qs_args_if_not_in_url( $query_string, array $args_to_check, $url ) {
-	$parsed_url = @parse_url( $url );
+	$parsed_url = parse_url( $url );
+
 	if ( ! empty( $parsed_url['query'] ) ) {
 		parse_str( $parsed_url['query'], $parsed_query );
+
 		foreach ( $args_to_check as $qv ) {
 			if ( ! isset( $parsed_query[ $qv ] ) ) {
 				$query_string = remove_query_arg( $qv, $query_string );
@@ -619,6 +798,7 @@
 	} else {
 		$query_string = remove_query_arg( $args_to_check, $query_string );
 	}
+
 	return $query_string;
 }
 
@@ -631,7 +811,8 @@
  * @return string The altered URL.
  */
 function strip_fragment_from_url( $url ) {
-	$parsed_url = @parse_url( $url );
+	$parsed_url = parse_url( $url );
+
 	if ( ! empty( $parsed_url['host'] ) ) {
 		// This mirrors code in redirect_canonical(). It does not handle every case.
 		$url = $parsed_url['scheme'] . '://' . $parsed_url['host'];
@@ -652,21 +833,67 @@
 }
 
 /**
- * Attempts to guess the correct URL based on query vars
+ * Attempts to guess the correct URL for a 404 request based on query vars.
  *
  * @since 2.3.0
  *
  * @global wpdb $wpdb WordPress database abstraction object.
  *
- * @return false|string The correct URL if one is found. False on failure.
+ * @return string|false The correct URL if one is found. False on failure.
  */
 function redirect_guess_404_permalink() {
 	global $wpdb;
 
+	/**
+	 * Filters whether to attempt to guess a redirect URL for a 404 request.
+	 *
+	 * Returning a false value from the filter will disable the URL guessing
+	 * and return early without performing a redirect.
+	 *
+	 * @since 5.5.0
+	 *
+	 * @param bool $do_redirect_guess Whether to attempt to guess a redirect URL
+	 *                                for a 404 request. Default true.
+	 */
+	if ( false === apply_filters( 'do_redirect_guess_404_permalink', true ) ) {
+		return false;
+	}
+
+	/**
+	 * Short-circuits the redirect URL guessing for 404 requests.
+	 *
+	 * Returning a non-null value from the filter will effectively short-circuit
+	 * the URL guessing, returning the passed value instead.
+	 *
+	 * @since 5.5.0
+	 *
+	 * @param null|string|false $pre Whether to short-circuit guessing the redirect for a 404.
+	 *                               Default null to continue with the URL guessing.
+	 */
+	$pre = apply_filters( 'pre_redirect_guess_404_permalink', null );
+	if ( null !== $pre ) {
+		return $pre;
+	}
+
 	if ( get_query_var( 'name' ) ) {
-		$where = $wpdb->prepare( 'post_name LIKE %s', $wpdb->esc_like( get_query_var( 'name' ) ) . '%' );
+		/**
+		 * Filters whether to perform a strict guess for a 404 redirect.
+		 *
+		 * Returning a truthy value from the filter will redirect only exact post_name matches.
+		 *
+		 * @since 5.5.0
+		 *
+		 * @param bool $strict_guess Whether to perform a strict guess. Default false (loose guess).
+		 */
+		$strict_guess = apply_filters( 'strict_redirect_guess_404_permalink', false );
 
-		// if any of post_type, year, monthnum, or day are set, use them to refine the query
+		if ( $strict_guess ) {
+			$where = $wpdb->prepare( 'post_name = %s', get_query_var( 'name' ) );
+		} else {
+			$where = $wpdb->prepare( 'post_name LIKE %s', $wpdb->esc_like( get_query_var( 'name' ) ) . '%' );
+		}
+
+		// If any of post_type, year, monthnum, or day are set, use them to refine the query.
 		if ( get_query_var( 'post_type' ) ) {
 			$where .= $wpdb->prepare( ' AND post_type = %s', get_query_var( 'post_type' ) );
 		} else {
@@ -683,13 +910,16 @@
 			$where .= $wpdb->prepare( ' AND DAYOFMONTH(post_date) = %d', get_query_var( 'day' ) );
 		}
 
+		// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
 		$post_id = $wpdb->get_var( "SELECT ID FROM $wpdb->posts WHERE $where AND post_status = 'publish'" );
+
 		if ( ! $post_id ) {
 			return false;
 		}
+
 		if ( get_query_var( 'feed' ) ) {
 			return get_post_comments_feed_link( $post_id, get_query_var( 'feed' ) );
-		} elseif ( get_query_var( 'page' ) && 1 < get_query_var( 'page' ) ) {
+		} elseif ( get_query_var( 'page' ) > 1 ) {
 			return trailingslashit( get_permalink( $post_id ) ) . user_trailingslashit( get_query_var( 'page' ), 'single_paged' );
 		} else {
 			return get_permalink( $post_id );
@@ -707,10 +937,11 @@
  *
  * @since 3.4.0
  *
- * @global WP_Rewrite $wp_rewrite
+ * @global WP_Rewrite $wp_rewrite WordPress rewrite component.
  */
 function wp_redirect_admin_locations() {
 	global $wp_rewrite;
+
 	if ( ! ( is_404() && $wp_rewrite->using_permalinks() ) ) {
 		return;
 	}
@@ -722,7 +953,8 @@
 		site_url( 'dashboard', 'relative' ),
 		site_url( 'admin', 'relative' ),
 	);
-	if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $admins ) ) {
+
+	if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $admins, true ) ) {
 		wp_redirect( admin_url() );
 		exit;
 	}
@@ -732,7 +964,8 @@
 		home_url( 'login', 'relative' ),
 		site_url( 'login', 'relative' ),
 	);
-	if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $logins ) ) {
+
+	if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $logins, true ) ) {
 		wp_redirect( wp_login_url() );
 		exit;
 	}