maybe_add_existing_user_to_blog() returns http response 500 even on success

[drzaphod]

File: wp-includes/ms-functions.php
Function: maybe_add_existing_user_to_blog()
Line: 1938

Calling this function will return HTTP 500 (Server Error) even when the function succeeds. This can cause problems when a caching server such as Varnish reacts unfavorably to the 500 and redirects the user to a sorry page.

Replace line 1938 with the following to correct.

wp_die( sprintf( __( 'You have been added to this site. Please visit the <a href="%s">homepage</a> or <a href="%s">log in</a> using your username and password.' ), home_url(), admin_url() ), __( 'WordPress &rsaquo; Success' ), array( 'response' => 200 ) );

[TobiasBg]

Thanks, @MikeHansenMe. Should we maybe add the same response code to the other wp_die() call as well? It also appears to be a legit user-facing error message.

[MikeHansenMe]

Good call @TobiasBg

[jeremyfelt]

Thanks for the report @drzaphod!

I think we can stick to only adding a 200 response to the success message in 31224.diff. Keeping the default as 500 for the actual error matches many other cases in core right now.

[jeremyfelt]

In 31514:

Use response code 200 when an existing network user joins a site via invitation.

Pass a response code of 200 to wp_die() when a user is successfully added to an individual site after using the /newbloguser/ URL from an invite email. This is a user facing success message.

Props MikeHansenMe.

Fixes #31224.