It appears as if when saving a user as "Browser Timezone" after changing the timezone to something other than "Browser Timezone" that the value is saved as an empty string instead of nil.

Check it out:

katello=# select count(id) from users where timezone = '';
count
-------
1
(1 row)

(byebug) cookies[:timezone]
"America/New_York"
(byebug) User.current.try(:timezone)
""

Which will obviously cause this time zone code [1]:

client_timezone = User.current.try(:timezone) || cookies[:timezone]
Time.zone = client_timezone if client_timezone.present?

to not set the correct timezone since User.current.try(:timezone) will be true and thus client_timezone.present? will be false.

Steps to Reproduce¶

1. Change a user's timezone to something other than "Browser timezone"
2. Change the same user's timezone back to "Browser timezone"
3. Note that user.timezone is an empty string

[1] https://github.com/theforeman/foreman/blob/develop/app/controllers/concerns/application_shared.rb#L9-L13