Amit Sukapure

@bcworkz sorry for not replying to your comment.
Thanks for your answer and findings regarding above issue. I have too researched in that way and maybe wp_auth_set_cookie was unable to set the right cookie as you’ve explained in your comment.

Although after few more tries we’ve found a good workaround 🙂

We are now simply “post” the user data to wp-login.php after wp_install
Closing the ticket, thanks again for your support.

Right!
Let me give you some background 🙂
I’m a developer in One.com and we are hosting service provider. We have service called “1-click WordPress installer” where we are using /wp-content/install.php to process WP installation with custom UI.

PS – We are handling installation via ajax.

@bcworkz thanks for your reply. I totally understand what you want to say.
I have my custom /wp-content/install.php just changing the look of the installation process.

Where I’ve called wp_install method and next I’m setting the cookie using wp_set_auth_cookie which was working nicely before 4.7.4

Here is my code snippet –

$result = wp_install( $site_title, $username, $email, $public, $deprecated = '', $password, $language );

if( ! isset( $result[ 'user_id' ] ) || $result[ 'user_id' ] == '' ) {
	$response[ 'message' ] = 'Not installed';
} else {
	$login_data = array();
	$login_data['user_login'] = $username;
	$login_data['user_password'] = $password;
	$login_data['remember'] = true;
	$user_verify = wp_signon($login_data, true);
		
	if (is_wp_error($user_verify)) {
		$errors[] = 'Invalid username or password. Please try again!';
	} else {
		wp_set_auth_cookie($user_verify->ID);
	}
}