SiteAliasFileLoader isn't handling if createAliasRecordsFromSiteData doesn't find a yaml file

[Skarlso]

This part of the code:

drush/src/SiteAlias/SiteAliasFileLoader.php

Line 176 in 6d78d47

foreach ($siteData as $envName => $data) {

doesn't handle if $siteData if false. Which can be the result of a loadSiteDataFromFile.

This will result in Drush saying: site alias not found, but doesn't explain why not, leaving the user up to try and investigate the failure. And an ugly Warning message for drush site:alias like this:

 [warning] Invalid argument supplied for foreach() SiteAliasFileLoader.php:176