I render a single_button object using the core renderer's method render_single_button, i.e. from a mustache template. The single_button is instantiated using a moodle_url object.

If that moodle_url object is created from a URL that contains slash arguments, the effective target URL of the single_button completely ignores the slash arguments. Example URL: https://demo.nextcloud.com/ogh3roos/index.php/apps/oauth2/authorize

EXPECTED: A button within a form whose action URL is "https://demo.nextcloud.com/ogh3roos/index.php/apps/oauth2/authorize".

ACTUAL: A button within a form whose action URL is "https://demo.nextcloud.com/ogh3roos/index.php".

SAMPLE CODE:

// with an existing oauth client; must be configured with an issuer that uses slasharguments as its authorization_endpoint:

$renderer->render(new \single_button($oauthclient->get_login_url(), 'Login'));

// quick demo without oauth configuration:

$renderer->render(new \single_button(new \moodle_url("https://demo.nextcloud.com/ogh3roos/index.php/apps/oauth2/authorize"), 'Login'));