When tab_width config option (or command line argument) is used, then each tab is converted to 4 spaces. In PHPCS 1.5.x this results in every sniff, that is looking specifically for TABs will fail, including DisallowSpaceIndentSniff.

In PHPCS 2.x version of that sniff this is fixed, because orig_content is used for checks, which still has TABs.

I wonder how safe it is to use tab_width option for projects, where TABs are used for indentation. I though it's main purpose was to help projects where indentation is done with spaces to deal with accidentally found TABs. Am I right?