Display local time in user's profile

app/helpers/time_zone_helper.rb

@@ -31,4 +31,9 @@ module TimeZoneHelper
       }.slice(*attrs)
     end
   end
+
+  def local_time(timezone)
+    time_zone_instance = ActiveSupport::TimeZone.new(timezone) || Time.zone
+    time_zone_instance.now.strftime("%-l:%M %p")
+  end
 end

app/views/users/show.html.haml

@@ -73,6 +73,10 @@
                 = sprite_icon('location', css_class: 'fgray')
                 %span{ itemprop: 'addressLocality' }
                   = @user.location
+            .profile-link-holder.middle-dot-divider-sm.d-block.d-sm-inline.mb-1.mb-sm-0
+              = sprite_icon('clock', css_class: 'fgray')
+              %span
+                = local_time(@user.timezone)
             - unless work_information(@user).blank?
               .profile-link-holder.middle-dot-divider-sm.d-block.d-sm-inline
                 = sprite_icon('work', css_class: 'fgray')

doc/administration/timezone.md

@@ -44,15 +44,17 @@ gitlab-ctl restart
 
 ## Changing time zone per user
 
-To allow users to change the time zone in their profile, the feature flag `user_time_settings` should be enabled:
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/issues/57654) in GitLab 11.11, disabled by default behind `user_time_settings` [feature flag](feature_flags.md).
+> - [Enabled by default](https://gitlab.com/gitlab-org/gitlab/-/issues/29669) in GitLab 13.9.
+> - [Feature flag removed](https://gitlab.com/gitlab-org/gitlab/-/issues/29669) in GitLab 14.1.
 
-1. [Start a Rails console session](operations/rails_console.md).
-1. Enable the feature flag:
+This setting controls the local time displayed on a user's profile.
+See [&280](https://gitlab.com/groups/gitlab-org/-/epics/280) for other planned features.
 
-   ```ruby
-   Feature.enable(:user_time_settings)
-   ```
+NOTE:
+If a user has not set their time zone, it defaults to the time zone [configured at the instance level](#changing-your-time-zone). On GitLab.com, the default time zone is UTC.
 
-1. You should now be able to see the timezone dropdown in the users' **Settings > Profile** page.
+1. Navigate to [your user settings](../user/profile/index.md#access-your-user-settings).
+1. Select your time zone from the dropdown.
 
-   ![User Time Zone Settings](img/time_zone_settings.png)
+![User Time Zone Settings](img/time_zone_settings.png)

spec/features/users/show_spec.rb

@@ -57,6 +57,56 @@ RSpec.describe 'User page' do
       end
     end
 
+    context 'location' do
+      let_it_be(:location) { 'San Francisco, CA' }
+
+      context 'when location is set' do
+        let_it_be(:user) { create(:user, location: location) }
+
+        it 'shows location' do
+          subject
+
+          expect(page).to have_content(location)
+        end
+      end
+
+      context 'when location is not set' do
+        it 'does not show location' do
+          subject
+
+          expect(page).not_to have_content(location)
+        end
+      end
+    end
+
+    context 'timezone' do
+      let_it_be(:timezone) { 'America/Los_Angeles' }
+
+      before do
+        travel_to Time.find_zone(timezone).local(2021, 7, 20, 15, 30, 45)
+      end
+
+      context 'when timezone is set' do
+        let_it_be(:user) { create(:user, timezone: timezone) }
+
+        it 'shows local time' do
+          subject
+
+          expect(page).to have_content('3:30 PM')
+        end
+      end
+
+      context 'when timezone is invalid' do
+        let_it_be(:user) { create(:user, timezone: 'Foo/Bar') }
+
+        it 'shows local time using the configured default timezone (UTC in this case)' do
+          subject
+
+          expect(page).to have_content('10:30 PM')
+        end
+      end
+    end
+
     context 'follow/unfollow and followers/following' do
       let_it_be(:followee) { create(:user) }
       let_it_be(:follower) { create(:user) }

spec/helpers/time_zone_helper_spec.rb

@@ -68,4 +68,24 @@ RSpec.describe TimeZoneHelper, :aggregate_failures do
       end
     end
   end
+
+  describe '#local_time' do
+    let_it_be(:timezone) { 'America/Los_Angeles' }
+
+    before do
+      travel_to Time.find_zone(timezone).local(2021, 7, 20, 15, 30, 45)
+    end
+
+    context 'when a valid timezone is passed' do
+      it 'returns local time' do
+        expect(helper.local_time(timezone)).to eq('3:30 PM')
+      end
+    end
+
+    context 'when an invalid timezone is passed' do
+      it 'returns local time using the configured default timezone (UTC in this case)' do
+        expect(helper.local_time('Foo/Bar')).to eq('10:30 PM')
+      end
+    end
+  end
 end