Derivative name in file name

I add #generate_location(io, context) method to change file name and wanted to add derivative name to path.

When creating derivative in cache storage context receives value for example {derivative: :thumb}
But when promoting - {derivative: [:thumb]} (array value)

Distiction is in this to methods, where one uses derivative_path(path)

Hi, thanks for reporting and finding the root cause. I’ve just pushed a fix to master.