Ticket #31106: 31106.diff

src/wp-includes/user.php

@@ -1630 +1630 @@
 }
 
 /**
+ * Checks whether a given nicename exists.
+ *
+ * @since 4.2.0
+ *
+ * @param string $nicename Nicename.
+ * @return null|int The user's ID on success, and null on failure.
+ */
+function nicename_exists( $nicename ) {
+        if ( $user = get_user_by( 'slug', $nicename ) ) {
+                return $user->ID;
+        } else {
+                return null;
+        }
+}
+
+/**
  * Checks whether the given email exists.
  *
  * @since 2.1.0

tests/phpunit/tests/user.php

@@ -664 +664 @@
                 $user = get_userdata( $user->ID );
                 $this->assertEmpty( $user->user_activation_key );
         }
+
+        function test_nicename_exists() {
+                $user_id = $this->factory->user->create( array( 'user_nicename' => 'nicenameexists' ) );
+                $this->assertEquals( nicename_exists( 'nicenameexists' ), $user_id );
+                wp_delete_user( $user_id );
+                $this->assertEquals( null, nicename_exists( 'nicenameexists' ) );
+        }
 }