On: Ruby Lazy Enumerators

[andruby]

Good to know: the lazy block is executed in a fiber, and fibers don’t share Thread.current.

It took me hours to debug why Rails I18n.locale was not honored inside the block.

[why-el → andruby]

Can you elaborate? What were you doing to the locale? Changing it?

[nurettin → why-el]

Perhaps gp means that the i18n data was initialized as thread-local, so it was missing in other threads.

[andruby → why-el]

Rails uses I18n.locale as a "global variable" to store the locale of the request. Behind the scenes this is stored in Thread.current[]. So if you have a request that sets the locale to non-default one and you perform some work inside a lazy block, I18n.locale will return an incorrect value inside that block.