Magento2 Multistore Headers already sent

Question

I recently upgraded my Magento store to 2.3.1. The main store works just fine, however, my other store (multi-store instance) brings up this error:

Warning: stream_wrapper_unregister(): Unable to unregister protocol phar:// in /home/site/public_html/app/bootstrap.php on line 11

It then redirects to a report page, the relevant log file shows:

{"0":"Warning: Cannot modify header information - headers already sent by (output started at /home/site/public_html/app/bootstrap.php:11)}

I've cleared out the var/ folders, run the:

$ php bin/magento setup:upgrade
$ php bin/magento setup:di:compile
$ php bin/magento setup:static-content:deploy -f
$ php bin/magento cache:clean

Going to app/bootstrap.php line 11 shows:

stream_wrapper_unregister('phar');

Commenting it out works ... but that feels hacky and dirty.

What's the proper way to fix this?

Server info:

PHP: 7.2.16

CentOS 7

Thanks,

Answer 1

The issue is after you modified your index.php file you left white space at the top prior to <?php OR you modified the end of the index.php file to include a ?> which it should not

I know this is very old, but i had the issue, im sure many looked this up, thought maybe it should include the solution