I18n::ArgumentError with i18n v0.8.2+

[cbeer]

Steps to reproduce

https://gist.github.com/cbeer/140cb717506e97181644c59faaef92b2

Using i18n v0.8.2+, calling unauthorized_message causes an exception.

Upstream, they introduced a new check in 0.8.2: ruby-i18n/i18n#236.

Cancancan is explicitly passing a nil key:

cancancan/lib/cancan/ability.rb

Line 225 in 2d21842

message = I18n.translate(nil, variables.merge(scope: :unauthorized, default: keys + ['']))

.

Expected behavior

The unauthorized message should be provided.

Actual behavior

An exception is thrown:

I18n::ArgumentError: I18n::ArgumentError
    /Users/cabeer/.gem/ruby/2.4.1/gems/i18n-0.8.3/lib/i18n.rb:152:in `translate'
    /Users/cabeer/.gem/ruby/2.4.1/gems/cancancan-2.0.0/lib/cancan/ability.rb:226:in `unauthorized_message'

System configuration

Rails version: 5.0.2

Ruby version: 2.3.4

CanCanCan version 1.17.0

[radar]

I have just released I18n 0.8.4 which should fix this issue. Please try it out :)

[clemens]

This might be just my opinion but I think it's more CanCanCan's fault than i18n's: A call to I18n.translate with nil doesn't semantically make sense. It literally says "Give the translation of nothingness". I think what CanCanCan means to do here is use a fallback chain, but it takes a shortcut by piggybacking on the default option. What it should instead do is build up an array of potential keys and then shift off the first element as the starting key – similar to what simple_form does here: https://github.com/plataformatec/simple_form/blob/master/lib/simple_form/inputs/base.rb#L173-L189. Then i18n could be fixed accordingly as well.

[coorasse]

I agree with @clemens , PR is welcome!

[coorasse]

is the problem with i18n solved now @cbeer ?

[clemens]

I guess it is solved by the i18n update but (IMO) it's not fixed in the right way ...