Bugfix: Always use the default language when generating emails.

There was a race condition issue when the application was generating an
email and was using a language that was previously being used in other
request.

2 files changed, 28 insertions, 7 deletions

diff --git a/lib/api/api.rb b/lib/api/api.rb
index 52cd7cbe3db..ac113c5200d 100644
--- a/lib/api/api.rb
+++ b/lib/api/api.rb
@@ -45,9 +45,9 @@ module API
     end
 
     before { allow_access_with_scope :api }
-    before { Gitlab::I18n.set_locale(current_user) }
+    before { Gitlab::I18n.locale = current_user&.preferred_language }
 
-    after { Gitlab::I18n.reset_locale }
+    after { Gitlab::I18n.use_default_locale }
 
     rescue_from Gitlab::Access::AccessDeniedError do
       rack_response({ 'message' => '403 Forbidden' }.to_json, 403)
diff --git a/lib/gitlab/i18n.rb b/lib/gitlab/i18n.rb
index 3411516319f..5ab3eeb3aff 100644
--- a/lib/gitlab/i18n.rb
+++ b/lib/gitlab/i18n.rb
@@ -12,15 +12,36 @@ module Gitlab
       AVAILABLE_LANGUAGES.keys
     end
 
-    def set_locale(current_user)
-      requested_locale = current_user&.preferred_language || ::I18n.default_locale
-      locale = FastGettext.set_locale(requested_locale)
-      ::I18n.locale = locale
+    def locale
+      FastGettext.locale
     end
 
-    def reset_locale
+    def locale=(locale_string)
+      requested_locale = locale_string || ::I18n.default_locale
+      new_locale = FastGettext.set_locale(requested_locale)
+      ::I18n.locale = new_locale
+    end
+
+    def use_default_locale
       FastGettext.set_locale(::I18n.default_locale)
       ::I18n.locale = ::I18n.default_locale
     end
+
+    def with_locale(locale_string)
+      original_locale = locale
+
+      self.locale = locale_string
+      yield
+    ensure
+      self.locale = original_locale
+    end
+
+    def with_user_locale(user, &block)
+      with_locale(user&.preferred_language, &block)
+    end
+
+    def with_default_locale(&block)
+      with_locale(::I18n.default_locale, &block)
+    end
   end
 end