Strange error while translating the word "admin" in Rails - ruby-on-rails

Question

Observe the following console output:
$ grep -IirF admin config/locales/
config/locales/static.el.yml: Administered: Χορηγήθηκε
config/locales/el.yml: admin: διαχειριστής
config/locales/system.el.yml: administered: Χορηγήθηκε
$ rails c
Running via Spring preloader in process 8176
Loading development environment (Rails 6.0.2.1)
irb(main):001:0> helper.t('admin1', locale: :el)
=> "admin1"
irb(main):002:0> helper.t('admin', locale: :el)
=> "διαχειριστής"
irb(main):003:0> helper.t('admin1', locale: :en)
=> "admin1"
irb(main):004:0> helper.t('admin', locale: :en)
=> {:js=>{true=>true, false=>false, :is_present=>"Is present", :is_blank=>"Is blank", :date=>"Date ...", :between_and_=>"Between ... and ...", :today=>"Today", :yesterday=>"Yesterday", :this_week=>"This week", :last_week=>"Last week", :number=>"Number ...", :contains=>"Contains", :is_exactly=>"Is exactly", :starts_with=>"Starts with", :ends_with=>"Ends with", :too_many_objects=>"Too many objects, use search box above", :no_objects=>"No objects found"}, :loading=>"Loading...", :toggle_navigation=>"Toggle navigation", :home=>{:name=>"Home"}, :pagination=>{:previous=>"« Prev", :next=>"Next »", :truncate=>"…"}, :misc=>{:search=>"Search", :filter=>"Filter", :refresh=>"Refresh", :show_all=>"Show all", :add_filter=>"Add filter", :bulk_menu_title=>"Selected items", :remove=>"Remove", :add_new=>"Add new", :chosen=>"Chosen %{name}", :chose_all=>"Choose all", :clear_all=>"Clear all", :up=>"Up", :down=>"Down", :navigation=>"Navigation", :root_navigation=>"Actions", :navigation_static_label=>"Links", :log_out=>"Log out", :time_ago=>"%{time} ago", :ago=>"ago", :more=>"Plus %{count} more %{models_name}"}, :flash=>{:successful=>"%{name} successfully %{action}", :error=>"%{name} failed to be %{action}", :noaction=>"No actions were taken", :model_not_found=>"Model '%{model}' could not be found", :object_not_found=>"%{model} with id '%{id}' could not be found"}, :table_headers=>{:model_name=>"Model name", :last_created=>"Last created", :records=>"Records", :username=>"User", :changes=>"Changes", :created_at=>"Date/Time", :item=>"Item", :message=>"Message"}, :actions=>{:dashboard=>{:title=>"Site Administration", :menu=>"Dashboard", :breadcrumb=>"Dashboard"}, :index=>{:title=>"List of %{model_label_plural}", :menu=>"List", :breadcrumb=>"%{model_label_plural}"}, :show=>{:title=>"Details for %{model_label} '%{object_label}'", :menu=>"Show", :breadcrumb=>"%{object_label}"}, :show_in_app=>{:menu=>"Show in app"}, :new=>{:title=>"New %{model_label}", :menu=>"Add new", :breadcrumb=>"New", :link=>"Add a new %{model_label}", :done=>"created"}, :edit=>{:title=>"Edit %{model_label} '%{object_label}'", :menu=>"Edit", :breadcrumb=>"Edit", :link=>"Edit this %{model_label}", :done=>"updated"}, :delete=>{:title=>"Delete %{model_label} '%{object_label}'", :menu=>"Delete", :breadcrumb=>"Delete", :link=>"Delete '%{object_label}'", :done=>"deleted"}, :bulk_delete=>{:title=>"Delete %{model_label_plural}", :menu=>"Multiple delete", :breadcrumb=>"Multiple delete", :bulk_link=>"Delete selected %{model_label_plural}"}, :export=>{:title=>"Export %{model_label_plural}", :menu=>"Export", :breadcrumb=>"Export", :link=>"Export found %{model_label_plural}", :bulk_link=>"Export selected %{model_label_plural}", :done=>"exported"}, :history_index=>{:title=>"History for %{model_label_plural}", :menu=>"History", :breadcrumb=>"History"}, :history_show=>{:title=>"History for %{model_label} '%{object_label}'", :menu=>"History", :breadcrumb=>"History"}}, :form=>{:cancel=>"Cancel", :basic_info=>"Basic info", :required=>"Required", :optional=>"Optional", :one_char=>"character", :char_length_up_to=>"length up to", :char_length_of=>"length of", :save=>"Save", :save_and_add_another=>"Save and add another", :save_and_edit=>"Save and edit", :all_of_the_following_related_items_will_be_deleted=>"? The following related items may be deleted or orphaned:", :are_you_sure_you_want_to_delete_the_object=>"Are you sure you want to delete this %{model_name}", :confirmation=>"Yes, I'm sure", :bulk_delete=>"The following objects will be deleted, which may delete or orphan some of their related dependencies:", :new_model=>"%{name} (new)"}, :export=>{:confirmation=>"Export to %{name}", :select=>"Select fields to export", :select_all_fields=>"Select All Fields", :fields_from=>"Fields from %{name}", :fields_from_associated=>"Fields from associated %{name}", :display=>"Display %{name}: %{type}", :options_for=>"Options for %{name}", :empty_value_for_associated_objects=>"<empty>", :click_to_reverse_selection=>"Click to reverse selection", :csv=>{:header_for_root_methods=>"%{name}", :header_for_association_methods=>"%{name} [%{association}]", :encoding_to=>"Encode to", :encoding_to_help=>"Choose output encoding. Leave empty to let current input encoding untouched: (%{name})", :skip_header=>"No header", :skip_header_help=>"Do not output a header (no fields description)", :default_col_sep=>",", :col_sep=>"Column separator", :col_sep_help=>"Leave blank for default ('%{value}')"}}, :history_rollback=>{:cancel=>"Cancel", :confirm=>"Are you sure?", :table_headers=>{:changes=>"Changes", :field=>"Field", :rollback=>"Rollback", :view_changes=>"View changes"}, :rollback_destroy=>"Rolled back newly-created record by destroying it.", :rollback_success=>"Rolled back changes to this record.", :rollback_impossible=>"Couldn't rollback. Sorry.", :version_not_found=>"Version does not exist.", :rollback_violates_foreign_key=>"Couldn't rollback: this model links to another model, which doesn't exists."}}
Translation seems to work correctly, except for a single word: 'admin'
Can someone explain this error, and how to overcome it?

Answer 1

This most likely has to do with a conflict with some other gem that adds an admin namespace, like maybe ActiveAdmin or rails_admin, or maybe a role authorization plugin. That's why it's returning a hash instead of a single string value.
Some other code or gem has loaded the admin key to look something like this:
en:
admin:
js:
'true': true
'false': false
is_present: Is present
....etc....
I would suggest nesting your key to avoid the conflict with something like:
en:
user_type:
admin: Administrator
helper.t('user_type.admin')
I would also suggest setting up the i18n-tasks gem, which can find and correct issues with translation files, as part of your CI or test suite, which I believe would have detected this conflict with the command i18n-tasks health and shown that admin is a dupilcate key, so when your yaml files and the gem's get combined, only the last one to write to the translations hash will be preserved.