Administration: A11y: Prevent empty author link in list tables.

If the author display name is unknown, show an `emdash` and screen reader text `(no author)`, consistent with other cases where information is unknown. Fix an issue where an unknown author name displayed as an invisible link with no text.

Props kkmuffme, hdkothari81, shailu25, snehapatil02, sabernhardt, faisal03, rishavdutta, sumitbagthariya16, joedolson.
Fixes #62913.

git-svn-id: https://develop.svn.wordpress.org/trunk@60032 602fd350-edb4-49c9-b593-d223f7449a82

Author: joedolson

src/wp-admin/includes/class-wp-media-list-table.php

@@ -503,15 +503,22 @@ public function column_title( $post ) {
 	 * Handles the author column output.
 	 *
 	 * @since 4.3.0
+	 * @since 6.8.0 Added fallback text when author's name is unknown.
 	 *
 	 * @param WP_Post $post The current WP_Post object.
 	 */
 	public function column_author( $post ) {
-		printf(
-			'<a href="%s">%s</a>',
-			esc_url( add_query_arg( array( 'author' => get_the_author_meta( 'ID' ) ), 'upload.php' ) ),
-			get_the_author()
-		);
+		$author = get_the_author();
+
+		if ( ! empty( $author ) ) {
+			printf(
+				'<a href="%s">%s</a>',
+				esc_url( add_query_arg( array( 'author' => get_the_author_meta( 'ID' ) ), 'upload.php' ) ),
+				esc_html( $author )
+			);
+		} else {
+			echo '<span aria-hidden="true">&#8212;</span><span class="screen-reader-text">' . __( '(no author)' ) . '</span>';
+		}
 	}
 
 	/**

src/wp-admin/includes/class-wp-posts-list-table.php

@@ -1277,15 +1277,22 @@ public function column_comments( $post ) {
 	 * Handles the post author column output.
 	 *
 	 * @since 4.3.0
+	 * @since 6.8.0 Added fallback text when author's name is unknown.
 	 *
 	 * @param WP_Post $post The current WP_Post object.
 	 */
 	public function column_author( $post ) {
-		$args = array(
-			'post_type' => $post->post_type,
-			'author'    => get_the_author_meta( 'ID' ),
-		);
-		echo $this->get_edit_link( $args, get_the_author() );
+		$author = get_the_author();
+
+		if ( ! empty( $author ) ) {
+			$args = array(
+				'post_type' => $post->post_type,
+				'author'    => get_the_author_meta( 'ID' ),
+			);
+			echo $this->get_edit_link( $args, esc_html( $author ) );
+		} else {
+			echo '<span aria-hidden="true">&#8212;</span><span class="screen-reader-text">' . __( '(no author)' ) . '</span>';
+		}
 	}
 
 	/**