URLHelper::is_external not working for URLs without protocol

[hacknug]

Expected behavior

URLHelper::is_external returns false for external URL's with no protocol.

• URLHelper::is_external('//github.com/') => true
• URLHelper::is_external('https://github.com/') => true

Actual behavior

• URLHelper::is_external('//github.com/') => false
• URLHelper::is_external('https://github.com/') => true

Steps to reproduce behavior

var_dump( Timber\URLHelper::is_external( '//github.com/' ) );       // false
var_dump( Timber\URLHelper::is_external( 'http://github.com/' ) );  // true
var_dump( Timber\URLHelper::is_external( 'https://github.com/' ) ); // true

What version of WordPress, PHP and Timber are you using?

WordPress 5.0.3, PHP 7.2, Timber 1.8.4.

How did you install Timber? (for example, from GitHub, Composer/Packagist, WP.org?)

Upgraded to newest version via plugin updater in WordPress dashboard.

[palmiak]

First of all thanks for very detailed issue. You made our work much easier.

I took a look at the code and your are right. I think we need to change checking for http to checking for array('//', 'http') at the beginning of the url.

If you would like to make a pull request it would very appreciated.

[hacknug]

Sure thing! Will open a PR with the changes today, just wanted to make sure it made sense to change this.

[palmiak]

Great, thanks.