wp-login.php: login messages/errors

[mapumba]

When using the following code:

<?php
add_filter( 'wp_login_errors', function( $errors ) {

    $errors->add(
                'test_error',
                'Error Test'
        );

        $errors->add(
                'test_message',
                'Message Test',
                'message' // This is not an error..
        );

        return $errors;
}, 10 );

It only shows the "Message Test". This is because the variable "$error_message" in wp-login.php is used to display the message if there is only one error. But in this example the variable contains the Text of the Message and not the Error Message.

[SergeyBiryukov]

In 57142:

Login and Registration: Use correct variable to display a single error message.

When the wp_login_errors filter is used to add an error message followed by an instructional message, the former was not displayed and the latter was errouneously displayed twice above the login form.

This commit ensures that the error message is displayed as expected.

Follow-up to [56654].

Props mapumba.
Fixes #59983.

[SergeyBiryukov]

Hi there, welcome to WordPress Trac! Thanks for the patch.

Reopening for backporting to the 6.4 branch.

[jorbin]

[57142] looks good for 6.4 branch

[peterwilsoncc]

In 57288:

Login and Registration: Use correct variable to display a single error message.

When the wp_login_errors filter is used to add an error message followed by an instructional message, the former was not displayed and the latter was errouneously displayed twice above the login form.

This commit ensures that the error message is displayed as expected.

Follow-up to [56654].

Reviewed by jorbin.
Merges [57142] to the 6.4 branch.

Props mapumba, SergeyBiryukov.
Fixes #59983.