Regression with Rack::File.new(nil)

[gverger]

Hello,

I updated rack to 2.1.0 on my Rails 6.0.2.1 app, and it broke with the active storage disk controller.
It seems that it comes from this line in rails, where Rack::File.new(nil) is called.

It has been changed here in version 2.1.0 of Rack.

On the git repository of Rails, it seems this code is not called anymore and that should be fixed in a subsequent version of Rails.

But browsing version 5.2 of Rails showed the same issue here, which makes me think the responsibility would come from Rack to fix it.

I think we could just fix it by expanding the root path only when the root path is not nil, but I am not familiar at all with this codebase and it might be more complicated than that.

[gverger]

FYI there was a Stackoverflow question here starting it: https://stackoverflow.com/questions/59691691/rails-typeerror-no-implicit-conversion-of-nil-into-string-when-loading-image/59693773#59693773

[tagliala]

Hi, I've stumbled into this

Found a duplicate of this issue: #1464

This has already been fixed on rack master via 1b82d84

[ioquatix]

I think the rails use case is fragile. We didn't expect root to be nil. However, we've reverted the change and added specs for this use case.