From 5556f3dde8c0ceeb71b644c3f0f00b4b3a0b65cf Mon Sep 17 00:00:00 2001
From: Robbe Van Petegem <git@robbevp.be>
Date: Sun, 12 Jul 2026 10:15:02 +0200
Subject: [PATCH 1/7] Return errors as json objects instead of strings

---
 app/controllers/albums_controller.rb          |  8 +-
 app/controllers/application_controller.rb     | 12 +++
 app/controllers/artists_controller.rb         |  8 +-
 app/controllers/auth_tokens_controller.rb     |  4 +-
 .../codec_conversions_controller.rb           |  6 +-
 app/controllers/codecs_controller.rb          |  6 +-
 app/controllers/cover_filenames_controller.rb |  4 +-
 app/controllers/genres_controller.rb          |  6 +-
 app/controllers/image_types_controller.rb     |  6 +-
 app/controllers/labels_controller.rb          |  6 +-
 app/controllers/locations_controller.rb       |  4 +-
 app/controllers/playlists_controller.rb       |  8 +-
 app/controllers/plays_controller.rb           |  2 +-
 app/controllers/tracks_controller.rb          |  6 +-
 app/controllers/users_controller.rb           |  6 +-
 config/locales/en.yml                         | 91 -------------------
 test/controllers/albums_controller_test.rb    |  6 +-
 test/controllers/artists_controller_test.rb   |  6 +-
 .../auth_tokens_controller_test.rb            |  1 +
 .../codec_conversions_controller_test.rb      | 12 ++-
 test/controllers/codecs_controller_test.rb    |  9 +-
 .../cover_filenames_controller_test.rb        |  1 +
 test/controllers/genres_controller_test.rb    |  6 +-
 .../image_types_controller_test.rb            |  7 +-
 test/controllers/labels_controller_test.rb    |  6 +-
 test/controllers/locations_controller_test.rb |  1 +
 test/controllers/playlists_controller_test.rb |  6 +-
 test/controllers/plays_controller_test.rb     |  1 +
 test/controllers/tracks_controller_test.rb    |  7 +-
 test/controllers/users_controller_test.rb     |  6 +-
 30 files changed, 101 insertions(+), 157 deletions(-)

diff --git a/app/controllers/albums_controller.rb b/app/controllers/albums_controller.rb
index 2cd99827..800ff72f 100644
--- a/app/controllers/albums_controller.rb
+++ b/app/controllers/albums_controller.rb
@@ -29,7 +29,7 @@ def create
     if @album.save
       render json: transform_album_for_json(@album), status: :created
     else
-      render json: @album.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@album), status: :unprocessable_content
     end
   end
 
@@ -37,12 +37,12 @@ def update
     if @album.update(transformed_attributes)
       render json: transform_album_for_json(@album), status: :ok
     else
-      render json: @album.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@album), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @album.errors, status: :unprocessable_content unless @album.destroy
+    render json: transform_errors_for_json(@album), status: :unprocessable_content unless @album.destroy
   end
 
   def destroy_empty
@@ -51,7 +51,7 @@ def destroy_empty
   end
 
   def merge
-    render json: @album.errors, status: :unprocessable_content unless @album.merge(Album.find(params.expect(:source_id)))
+    render json: transform_errors_for_json(@album), status: :unprocessable_content unless @album.merge(Album.find(params.expect(:source_id)))
   end
 
   private
diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index cfcfb67d..aa6b06e5 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -2,6 +2,9 @@ class ApplicationController < ActionController::API
   include Pundit::Authorization
   include ActionController::HttpAuthentication::Token::ControllerMethods
 
+  # This map only includes the type of validation errors that we could have inside the app
+  ERROR_TYPE_MAP = { blank: :required, taken: :not_unique }.freeze
+
   etag { params[:page] }
   etag { params[:per_page] }
 
@@ -42,6 +45,15 @@ def stale?(scope:, **)
     super(etag:, **)
   end
 
+  def transform_error_for_json(error)
+    { attribute: error.attribute, type: ERROR_TYPE_MAP[error.type] }
+  end
+
+  # This method expects an instance of a class that includes `ActiveModel::Errors`
+  def transform_errors_for_json(object)
+    { errors: object.errors.errors.map { transform_error_for_json(it) } }
+  end
+
   private
 
   def authenticate_user
diff --git a/app/controllers/artists_controller.rb b/app/controllers/artists_controller.rb
index a53736b0..b5af9a98 100644
--- a/app/controllers/artists_controller.rb
+++ b/app/controllers/artists_controller.rb
@@ -26,7 +26,7 @@ def create
     if @artist.save
       render json: transform_artist_for_json(@artist), status: :created
     else
-      render json: @artist.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@artist), status: :unprocessable_content
     end
   end
 
@@ -34,12 +34,12 @@ def update
     if @artist.update(transformed_attributes)
       render json: transform_artist_for_json(@artist), status: :ok
     else
-      render json: @artist.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@artist), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @artist.errors, status: :unprocessable_content unless @artist.destroy
+    render json: transform_errors_for_json(@artist), status: :unprocessable_content unless @artist.destroy
   end
 
   def destroy_empty
@@ -51,7 +51,7 @@ def destroy_empty
   end
 
   def merge
-    render json: @artist.errors, status: :unprocessable_content unless @artist.merge(Artist.find(params.expect(:source_id)))
+    render json: transform_errors_for_json(@artist), status: :unprocessable_content unless @artist.merge(Artist.find(params.expect(:source_id)))
   end
 
   private
diff --git a/app/controllers/auth_tokens_controller.rb b/app/controllers/auth_tokens_controller.rb
index 294fb671..b15e5fa5 100644
--- a/app/controllers/auth_tokens_controller.rb
+++ b/app/controllers/auth_tokens_controller.rb
@@ -33,12 +33,12 @@ def create
     if @auth_token.save
       render json: transform_auth_token_for_json_with_token(@auth_token), status: :created
     else
-      render json: @auth_token.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@auth_token), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @auth_token.errors, status: :unprocessable_content unless @auth_token.destroy
+    render json: transform_errors_for_json(@auth_token), status: :unprocessable_content unless @auth_token.destroy
   end
 
   private
diff --git a/app/controllers/codec_conversions_controller.rb b/app/controllers/codec_conversions_controller.rb
index f0af3e32..dd0f169c 100644
--- a/app/controllers/codec_conversions_controller.rb
+++ b/app/controllers/codec_conversions_controller.rb
@@ -23,7 +23,7 @@ def create
     if @codec_conversion.save
       render json: transform_codec_conversion_for_json(@codec_conversion), status: :created
     else
-      render json: @codec_conversion.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@codec_conversion), status: :unprocessable_content
     end
   end
 
@@ -31,12 +31,12 @@ def update
     if @codec_conversion.update(permitted_attributes(CodecConversion))
       render json: transform_codec_conversion_for_json(@codec_conversion), status: :ok
     else
-      render json: @codec_conversion.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@codec_conversion), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @codec_conversion.errors, status: :unprocessable_content unless @codec_conversion.destroy
+    render json: transform_errors_for_json(@codec_conversion), status: :unprocessable_content unless @codec_conversion.destroy
   end
 
   private
diff --git a/app/controllers/codecs_controller.rb b/app/controllers/codecs_controller.rb
index 4b5ea0d2..b25ad3ad 100644
--- a/app/controllers/codecs_controller.rb
+++ b/app/controllers/codecs_controller.rb
@@ -21,7 +21,7 @@ def create
     if @codec.save
       render json: transform_codec_for_json(@codec), status: :created
     else
-      render json: @codec.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@codec), status: :unprocessable_content
     end
   end
 
@@ -29,12 +29,12 @@ def update
     if @codec.update(permitted_attributes(@codec))
       render json: transform_codec_for_json(@codec), status: :ok
     else
-      render json: @codec.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@codec), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @codec.errors, status: :unprocessable_content unless @codec.destroy
+    render json: transform_errors_for_json(@codec), status: :unprocessable_content unless @codec.destroy
   end
 
   private
diff --git a/app/controllers/cover_filenames_controller.rb b/app/controllers/cover_filenames_controller.rb
index 2cedc366..a5b06daf 100644
--- a/app/controllers/cover_filenames_controller.rb
+++ b/app/controllers/cover_filenames_controller.rb
@@ -21,12 +21,12 @@ def create
     if @cover_filename.save
       render json: transform_cover_filename_for_json(@cover_filename), status: :created
     else
-      render json: @cover_filename.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@cover_filename), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @cover_filename.errors, status: :unprocessable_content unless @cover_filename.destroy
+    render json: transform_errors_for_json(@cover_filename), status: :unprocessable_content unless @cover_filename.destroy
   end
 
   private
diff --git a/app/controllers/genres_controller.rb b/app/controllers/genres_controller.rb
index 395476ca..b75b113d 100644
--- a/app/controllers/genres_controller.rb
+++ b/app/controllers/genres_controller.rb
@@ -21,7 +21,7 @@ def create
     if @genre.save
       render json: transform_genre_for_json(@genre), status: :created
     else
-      render json: @genre.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@genre), status: :unprocessable_content
     end
   end
 
@@ -29,12 +29,12 @@ def update
     if @genre.update(permitted_attributes(@genre))
       render json: transform_genre_for_json(@genre), status: :ok
     else
-      render json: @genre.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@genre), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @genre.errors, status: :unprocessable_content unless @genre.destroy
+    render json: transform_errors_for_json(@genre), status: :unprocessable_content unless @genre.destroy
   end
 
   def destroy_empty
diff --git a/app/controllers/image_types_controller.rb b/app/controllers/image_types_controller.rb
index 4fa7fbd7..d9d71d0a 100644
--- a/app/controllers/image_types_controller.rb
+++ b/app/controllers/image_types_controller.rb
@@ -21,7 +21,7 @@ def create
     if @image_type.save
       render json: transform_image_type_for_json(@image_type), status: :created
     else
-      render json: @image_type.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@image_type), status: :unprocessable_content
     end
   end
 
@@ -29,12 +29,12 @@ def update
     if @image_type.update(permitted_attributes(@image_type))
       render json: transform_image_type_for_json(@image_type), status: :ok
     else
-      render json: @image_type.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@image_type), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @image_type.errors, status: :unprocessable_content unless @image_type.destroy
+    render json: transform_errors_for_json(@image_type), status: :unprocessable_content unless @image_type.destroy
   end
 
   private
diff --git a/app/controllers/labels_controller.rb b/app/controllers/labels_controller.rb
index 7ff4e58c..37383420 100644
--- a/app/controllers/labels_controller.rb
+++ b/app/controllers/labels_controller.rb
@@ -21,7 +21,7 @@ def create
     if @label.save
       render json: transform_label_for_json(@label), status: :created
     else
-      render json: @label.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@label), status: :unprocessable_content
     end
   end
 
@@ -29,12 +29,12 @@ def update
     if @label.update(permitted_attributes(@label))
       render json: transform_label_for_json(@label), status: :ok
     else
-      render json: @label.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@label), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @label.errors, status: :unprocessable_content unless @label.destroy
+    render json: transform_errors_for_json(@label), status: :unprocessable_content unless @label.destroy
   end
 
   def destroy_empty
diff --git a/app/controllers/locations_controller.rb b/app/controllers/locations_controller.rb
index 427aa940..0f2a0fb0 100644
--- a/app/controllers/locations_controller.rb
+++ b/app/controllers/locations_controller.rb
@@ -21,12 +21,12 @@ def create
     if @location.save
       render json: transform_location_for_json(@location), status: :created
     else
-      render json: @location.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@location), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @location.errors, status: :unprocessable_content unless @location.destroy
+    render json: transform_errors_for_json(@location), status: :unprocessable_content unless @location.destroy
   end
 
   private
diff --git a/app/controllers/playlists_controller.rb b/app/controllers/playlists_controller.rb
index 84effa70..588b3cfc 100644
--- a/app/controllers/playlists_controller.rb
+++ b/app/controllers/playlists_controller.rb
@@ -21,7 +21,7 @@ def create
     if @playlist.save
       render json: transform_playlist_for_json(@playlist), status: :created
     else
-      render json: @playlist.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@playlist), status: :unprocessable_content
     end
   end
 
@@ -29,18 +29,18 @@ def update
     if @playlist.update(permitted_attributes(@playlist))
       render json: transform_playlist_for_json(@playlist), status: :ok
     else
-      render json: @playlist.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@playlist), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @playlist.errors, status: :unprocessable_content unless @playlist.destroy
+    render json: transform_errors_for_json(@playlist), status: :unprocessable_content unless @playlist.destroy
   end
 
   def add_item
     @item = @playlist.items.create(permitted_attributes(@playlist))
 
-    render json: @item.errors, status: :unprocessable_content unless @item.save
+    render json: transform_errors_for_json(@item), status: :unprocessable_content unless @item.save
   end
 
   private
diff --git a/app/controllers/plays_controller.rb b/app/controllers/plays_controller.rb
index 52ef0b69..8036bc2c 100644
--- a/app/controllers/plays_controller.rb
+++ b/app/controllers/plays_controller.rb
@@ -20,7 +20,7 @@ def create
     if @play.save
       render json: transform_play_for_json(@play), status: :created
     else
-      render json: @play.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@play), status: :unprocessable_content
     end
   end
 
diff --git a/app/controllers/tracks_controller.rb b/app/controllers/tracks_controller.rb
index 0ff5c5cd..fea7f5c3 100644
--- a/app/controllers/tracks_controller.rb
+++ b/app/controllers/tracks_controller.rb
@@ -26,7 +26,7 @@ def create
     if @track.save
       render json: transform_track_for_json(@track), status: :created
     else
-      render json: @track.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@track), status: :unprocessable_content
     end
   end
 
@@ -34,12 +34,12 @@ def update
     if @track.update(transformed_attributes)
       render json: transform_track_for_json(@track), status: :ok
     else
-      render json: @track.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@track), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @track.errors, status: :unprocessable_content unless @track.destroy
+    render json: transform_errors_for_json(@track), status: :unprocessable_content unless @track.destroy
   end
 
   def destroy_empty
diff --git a/app/controllers/users_controller.rb b/app/controllers/users_controller.rb
index cba20173..8ce23bef 100644
--- a/app/controllers/users_controller.rb
+++ b/app/controllers/users_controller.rb
@@ -21,7 +21,7 @@ def create
     if @user.save
       render json: transform_user_for_json(@user), status: :created
     else
-      render json: @user.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@user), status: :unprocessable_content
     end
   end
 
@@ -37,12 +37,12 @@ def update
     if @user.update(permitted_attributes(@user))
       render json: transform_user_for_json(@user), status: :ok
     else
-      render json: @user.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@user), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @user.errors, status: :unprocessable_content unless @user.destroy
+    render json: transform_errors_for_json(@user), status: :unprocessable_content unless @user.destroy
   end
 
   private
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 7126d8a8..a5fac261 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -30,97 +30,6 @@
 # available at http://guides.rubyonrails.org/i18n.html.
 
 en:
-  activerecord:
-    errors:
-      models:
-        album:
-          attributes:
-            title: 
-              blank: "albums.title-blank"
-        album_artists:
-          attributes:
-            name:
-              blank: "aa.name-blank"
-            order:
-              blank: "aa.order-blank"
-        album_label:
-          attributes:
-            catalogue_number: 
-              blank: "al.cat-blank"
-        artist:
-          attributes:
-            name:
-              blank: "artists.name-blank"
-        codec:
-          attributes:
-            mimetype: 
-              blank: "codec.mime-blank"
-            extension:
-              blank: "codec.ext-blank"
-              taken: "codec.ext-taken"
-        codec_conversion:
-          attributes:
-            name:
-              blank: "codecconv.nane-blank"
-              taken: "codecconv.name-taken"
-            ffmpeg_params:
-              blank: "codecconv.ffmpeg-blank"
-            resulting_codec:
-              blank: "codecconv.result-blank"
-        genre:
-          attributes:
-            name:
-              blank: "genre.name-blank"
-              taken: "genre.name-taken"
-        image_type:
-          attributes:
-            mimetype: 
-              blank: "image.mime-blank"
-            extension:
-              blank: "image.ext-blank"
-              taken: "image.ext-taken"
-        label:
-          attributes: 
-            name: 
-              blank: "label.name-blank"
-        location:
-          attributes:
-            path:
-              blank: "location.path-blank"
-              taken: "location.path-taken"
-        play:
-          attributes:
-            played_at:
-              blank: "play.played-at-blank"
-        track:
-          attributes:
-            title:
-              blank: "tracks.title-blank"
-            number:
-              blank: "tracks.number-blank"
-        track_artist:
-          attributes:
-            artist:
-              blank: "ta.artist-blank"
-            name:
-              blank: "ta.name-blank"
-              taken: "ta.name-taken"
-            order:
-              blank: "ta.order-blank"
-            role:
-              blank: "ta.role-blank"
-            track:
-              blank: "ta.track-blank"
-        user:
-          attributes:
-            name:
-              blank: "user.name-blank"
-            password_confirmation:
-              confirmation: "user.password-confirmation"
-            password_digest:
-              blank: "user.password-blank"
-            permission:
-              blank: "user.permission-blank"
   auth_tokens:
     create:
       wrong_credentials: 'user.wrong-credentials'
diff --git a/test/controllers/albums_controller_test.rb b/test/controllers/albums_controller_test.rb
index 62ef41df..5cf1e51a 100644
--- a/test/controllers/albums_controller_test.rb
+++ b/test/controllers/albums_controller_test.rb
@@ -74,6 +74,7 @@ class AlbumsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'title', 'type' => 'required' }
   end
 
   test 'should create dependent album_labels' do
@@ -153,9 +154,8 @@ class AlbumsControllerTest < ActionDispatch::IntegrationTest
     patch album_url(@album), params: { album: { release: @album.release, title: '' } }
 
     assert_response :unprocessable_content
-    @album.reload
-
-    assert_not_equal '', @album.title
+    assert_not_equal '', @album.reload.title
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'title', 'type' => 'required' }
   end
 
   test 'should clear review comment' do
diff --git a/test/controllers/artists_controller_test.rb b/test/controllers/artists_controller_test.rb
index 6a701e59..db61ad99 100644
--- a/test/controllers/artists_controller_test.rb
+++ b/test/controllers/artists_controller_test.rb
@@ -69,6 +69,7 @@ class ArtistsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should show artist' do
@@ -91,9 +92,8 @@ class ArtistsControllerTest < ActionDispatch::IntegrationTest
     patch artist_url(@artist), params: { artist: { name: '' } }
 
     assert_response :unprocessable_content
-    @artist.reload
-
-    assert_not_equal '', @artist.name
+    assert_not_equal '', @artist.reload.name
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should not update artist metadata for user' do
diff --git a/test/controllers/auth_tokens_controller_test.rb b/test/controllers/auth_tokens_controller_test.rb
index 942f8f48..95a0e410 100644
--- a/test/controllers/auth_tokens_controller_test.rb
+++ b/test/controllers/auth_tokens_controller_test.rb
@@ -74,6 +74,7 @@ class AuthTokensControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'user_agent', 'type' => 'required' }
   end
 
   test 'should show auth_token' do
diff --git a/test/controllers/codec_conversions_controller_test.rb b/test/controllers/codec_conversions_controller_test.rb
index 3691eaeb..e68ce2c4 100644
--- a/test/controllers/codec_conversions_controller_test.rb
+++ b/test/controllers/codec_conversions_controller_test.rb
@@ -90,6 +90,7 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'not_unique' }
   end
 
   test 'should not create codec_conversion with empty ffmpeg_params' do
@@ -103,6 +104,7 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'ffmpeg_params', 'type' => 'required' }
   end
 
   test 'should not create codec_conversion with empty name' do
@@ -116,6 +118,7 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should not create codec_conversion with non-existing resulting_codec' do
@@ -130,6 +133,7 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'resulting_codec', 'type' => 'required' }
   end
 
   test 'should create codec_conversion for admin' do
@@ -175,11 +179,13 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
 
   test 'should not update codec_conversion to empty name' do
     sign_in_as(create(:moderator))
-    patch codec_conversion_url(@codec_conversion), params: { codec_conversion: {
-      name: ''
-    } }
+
+    assert_no_changes '@codec_conversion.reload.name' do
+      patch codec_conversion_url(@codec_conversion), params: { codec_conversion: { name: '' } }
+    end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should update codec_conversion for admin' do
diff --git a/test/controllers/codecs_controller_test.rb b/test/controllers/codecs_controller_test.rb
index 5a47c906..1769cc59 100644
--- a/test/controllers/codecs_controller_test.rb
+++ b/test/controllers/codecs_controller_test.rb
@@ -50,16 +50,19 @@ class CodecsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'extension', 'type' => 'required' }
   end
 
   test 'should not create codec with missing mimetype' do
     sign_in_as(create(:moderator))
     codec = build(:codec)
+
     assert_difference('Codec.count', 0) do
       post codecs_url, params: { codec: { extension: codec.extension } }
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'mimetype', 'type' => 'required' }
   end
 
   test 'should create codec for moderator' do
@@ -96,9 +99,13 @@ class CodecsControllerTest < ActionDispatch::IntegrationTest
 
   test 'should not update codec when clearing mimetype' do
     sign_in_as(create(:moderator))
-    patch codec_url(@codec), params: { codec: { mimetype: '' } }
+
+    assert_no_changes '@codec.reload.mimetype' do
+      patch codec_url(@codec), params: { codec: { mimetype: '' } }
+    end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'mimetype', 'type' => 'required' }
   end
 
   test 'should update codec for moderator' do
diff --git a/test/controllers/cover_filenames_controller_test.rb b/test/controllers/cover_filenames_controller_test.rb
index 40b5a0c6..37fee62d 100644
--- a/test/controllers/cover_filenames_controller_test.rb
+++ b/test/controllers/cover_filenames_controller_test.rb
@@ -68,6 +68,7 @@ class CoverFilenamesControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'filename', 'type' => 'required' }
   end
 
   test 'should create cover_filename for moderator' do
diff --git a/test/controllers/genres_controller_test.rb b/test/controllers/genres_controller_test.rb
index 8597d9fd..ee744108 100644
--- a/test/controllers/genres_controller_test.rb
+++ b/test/controllers/genres_controller_test.rb
@@ -49,6 +49,7 @@ class GenresControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should create genre for moderator' do
@@ -88,9 +89,8 @@ class GenresControllerTest < ActionDispatch::IntegrationTest
     patch genre_url(@genre), params: { genre: { name: '' } }
 
     assert_response :unprocessable_content
-    @genre.reload
-
-    assert_not_equal '', @genre.name
+    assert_not_equal '', @genre.reload.name
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should update genre for moderator' do
diff --git a/test/controllers/image_types_controller_test.rb b/test/controllers/image_types_controller_test.rb
index 8f4b6f94..098ec72b 100644
--- a/test/controllers/image_types_controller_test.rb
+++ b/test/controllers/image_types_controller_test.rb
@@ -50,6 +50,7 @@ class ImageTypesControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'extension', 'type' => 'required' }
   end
 
   test 'should not create image_type without mimetype' do
@@ -60,6 +61,7 @@ class ImageTypesControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'mimetype', 'type' => 'required' }
   end
 
   test 'should create image_type for moderator' do
@@ -99,9 +101,8 @@ class ImageTypesControllerTest < ActionDispatch::IntegrationTest
     patch image_type_url(@image_type), params: { image_type: { mimetype: '' } }
 
     assert_response :unprocessable_content
-    @image_type.reload
-
-    assert_not_equal '', @image_type.mimetype
+    assert_not_equal '', @image_type.reload.mimetype
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'mimetype', 'type' => 'required' }
   end
 
   test 'should update image_type for moderator' do
diff --git a/test/controllers/labels_controller_test.rb b/test/controllers/labels_controller_test.rb
index a097fb74..87280c96 100644
--- a/test/controllers/labels_controller_test.rb
+++ b/test/controllers/labels_controller_test.rb
@@ -50,6 +50,7 @@ class LabelsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should create label for moderator' do
@@ -89,9 +90,8 @@ class LabelsControllerTest < ActionDispatch::IntegrationTest
     patch label_url(@label), params: { label: { name: '' } }
 
     assert_response :unprocessable_content
-    @label.reload
-
-    assert_not_equal '', @label.name
+    assert_not_equal '', @label.reload.name
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should update label for moderator' do
diff --git a/test/controllers/locations_controller_test.rb b/test/controllers/locations_controller_test.rb
index e6f92f44..b1e86d72 100644
--- a/test/controllers/locations_controller_test.rb
+++ b/test/controllers/locations_controller_test.rb
@@ -68,6 +68,7 @@ class LocationsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'path', 'type' => 'required' }
   end
 
   test 'should create location for moderator' do
diff --git a/test/controllers/playlists_controller_test.rb b/test/controllers/playlists_controller_test.rb
index 276c80af..aec8011e 100644
--- a/test/controllers/playlists_controller_test.rb
+++ b/test/controllers/playlists_controller_test.rb
@@ -66,6 +66,7 @@ class PlaylistsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should create personal playlist for current user if specified' do
@@ -97,9 +98,12 @@ class PlaylistsControllerTest < ActionDispatch::IntegrationTest
   end
 
   test 'should not update playlist with empty name' do
-    patch playlist_url(@playlist), params: { playlist: { name: '' } }
+    assert_no_changes '@playlist.reload.name' do
+      patch playlist_url(@playlist), params: { playlist: { name: '' } }
+    end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should create playlist items during update' do
diff --git a/test/controllers/plays_controller_test.rb b/test/controllers/plays_controller_test.rb
index 9f8b3d32..93f90827 100644
--- a/test/controllers/plays_controller_test.rb
+++ b/test/controllers/plays_controller_test.rb
@@ -75,6 +75,7 @@ class PlaysControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'played_at', 'type' => 'required' }
   end
 
   test 'should get stats and  not return play stats for other users' do
diff --git a/test/controllers/tracks_controller_test.rb b/test/controllers/tracks_controller_test.rb
index aea0e41e..0d90a7f2 100644
--- a/test/controllers/tracks_controller_test.rb
+++ b/test/controllers/tracks_controller_test.rb
@@ -72,6 +72,7 @@ class TracksControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'title', 'type' => 'required' }
   end
 
   test 'should not create track without album_id' do
@@ -81,6 +82,7 @@ class TracksControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'album', 'type' => 'required' }
   end
 
   test 'should create track for moderator' do
@@ -156,9 +158,8 @@ class TracksControllerTest < ActionDispatch::IntegrationTest
     patch track_url(@track), params: { track: { title: '' } }
 
     assert_response :unprocessable_content
-    @track.reload
-
-    assert_not_equal '', @track.title
+    assert_not_equal '', @track.reload.title
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'title', 'type' => 'required' }
   end
 
   test 'should clear review comment' do
diff --git a/test/controllers/users_controller_test.rb b/test/controllers/users_controller_test.rb
index b66db3d1..c0c2bcf9 100644
--- a/test/controllers/users_controller_test.rb
+++ b/test/controllers/users_controller_test.rb
@@ -50,6 +50,7 @@ class UsersControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should create user for admin' do
@@ -98,9 +99,8 @@ class UsersControllerTest < ActionDispatch::IntegrationTest
     patch user_url(@user), params: { user: { name: '' } }
 
     assert_response :unprocessable_content
-    @user.reload
-
-    assert_not_equal '', @user.name
+    assert_not_equal '', @user.reload.name
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should not update own permission if not admin' do

From a8b7f48c6f549c4f33290f33635ed99e028a5f83 Mon Sep 17 00:00:00 2001
From: Robbe Van Petegem <git@robbevp.be>
Date: Sun, 12 Jul 2026 10:26:57 +0200
Subject: [PATCH 2/7] Convert loose errors to consistent format

---
 app/controllers/application_controller.rb     |  9 +----
 app/controllers/auth_tokens_controller.rb     |  3 +-
 app/controllers/users_controller.rb           |  3 +-
 config/locales/en.yml                         | 39 -------------------
 test/controllers/albums_controller_test.rb    |  4 ++
 test/controllers/artists_controller_test.rb   |  4 ++
 .../auth_tokens_controller_test.rb            |  1 +
 .../codec_conversions_controller_test.rb      |  3 ++
 test/controllers/codecs_controller_test.rb    |  3 ++
 .../cover_filenames_controller_test.rb        |  4 ++
 test/controllers/genres_controller_test.rb    |  5 +++
 .../image_types_controller_test.rb            |  3 ++
 test/controllers/labels_controller_test.rb    |  5 +++
 test/controllers/locations_controller_test.rb |  4 ++
 test/controllers/playlists_controller_test.rb |  6 +++
 test/controllers/rescans_controller_test.rb   |  4 ++
 test/controllers/tracks_controller_test.rb    |  7 ++++
 test/controllers/users_controller_test.rb     |  2 +
 18 files changed, 59 insertions(+), 50 deletions(-)
 delete mode 100644 config/locales/en.yml

diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index aa6b06e5..99a0a963 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -64,16 +64,11 @@ def authenticate_user
   end
 
   def user_not_authorized(exc)
-    policy_name = exc.policy.class.to_s.underscore
-
     status = current_user.present? ? :forbidden : :unauthorized
-    render json: { status => [I18n.t("#{policy_name}.#{exc.query}",
-                                     scope: 'pundit',
-                                     default: :default)] },
-           status:
+    render json: { errors: [{ policy: exc.policy.class.to_s.underscore, type: status, action: exc.query }] }, status:
   end
 
   def model_not_found(exc)
-    render json: { not_found: ["#{exc.model.pluralize.downcase}.not-found"] }, status: :not_found
+    render json: { errors: [{ model: exc.model.downcase, type: :not_found }] }, status: :not_found
   end
 end
diff --git a/app/controllers/auth_tokens_controller.rb b/app/controllers/auth_tokens_controller.rb
index b15e5fa5..f646ec8d 100644
--- a/app/controllers/auth_tokens_controller.rb
+++ b/app/controllers/auth_tokens_controller.rb
@@ -19,8 +19,7 @@ def create
 
     user = User.find_by(name: params[:name])
     unless user.try(:authenticate, params[:password])
-      render json: { unauthorized: [I18n.t('auth_tokens.create.wrong_credentials')] },
-             status: :unauthorized
+      render json: { errors: [{ attribute: :base, type: :wrong_credentials }] }, status: :unauthorized
       return
     end
 
diff --git a/app/controllers/users_controller.rb b/app/controllers/users_controller.rb
index 8ce23bef..df5efbdd 100644
--- a/app/controllers/users_controller.rb
+++ b/app/controllers/users_controller.rb
@@ -29,8 +29,7 @@ def update
     if @user == current_user &&
        params[:user][:password].present? &&
        !@user.try(:authenticate, params[:user][:current_password])
-      render json: { unauthorized: [I18n.t('users.current_password_is_incorrect')] },
-             status: :unauthorized
+      render json: { errors: [{ attribute: :base, type: :incorrect_password }] }, status: :unauthorized
       return
     end
 
diff --git a/config/locales/en.yml b/config/locales/en.yml
deleted file mode 100644
index a5fac261..00000000
--- a/config/locales/en.yml
+++ /dev/null
@@ -1,39 +0,0 @@
-# Files in the config/locales directory are used for internationalization
-# and are automatically loaded by Rails. If you want to use locales other
-# than English, add the necessary files in this directory.
-#
-# To use the locales, use `I18n.t`:
-#
-#     I18n.t 'hello'
-#
-# In views, this is aliased to just `t`:
-#
-#     <%= t('hello') %>
-#
-# To use a different locale, set it with `I18n.locale`:
-#
-#     I18n.locale = :es
-#
-# This would use the information in config/locales/es.yml.
-#
-# The following keys must be escaped otherwise they will not be retrieved by
-# the default I18n backend:
-#
-# true, false, on, off, yes, no
-#
-# Instead, surround them with single quotes.
-#
-# en:
-#   'true': 'foo'
-#
-# To learn more, please read the Rails Internationalization guide
-# available at http://guides.rubyonrails.org/i18n.html.
-
-en:
-  auth_tokens:
-    create:
-      wrong_credentials: 'user.wrong-credentials'
-  users:
-      current_password_is_incorrect: 'user.current-password-incorrect'
-  pundit:
-    default: 'not-authorized'
diff --git a/test/controllers/albums_controller_test.rb b/test/controllers/albums_controller_test.rb
index 5cf1e51a..8c4b94eb 100644
--- a/test/controllers/albums_controller_test.rb
+++ b/test/controllers/albums_controller_test.rb
@@ -39,6 +39,7 @@ class AlbumsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'album_policy', 'type' => 'forbidden', 'action' => 'create?' }
   end
 
   test 'should create album for moderator' do
@@ -229,6 +230,7 @@ class AlbumsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'album_policy', 'type' => 'forbidden', 'action' => 'destroy?' }
   end
 
   test 'should destroy album for moderator' do
@@ -251,6 +253,7 @@ class AlbumsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'album_policy', 'type' => 'forbidden', 'action' => 'destroy_empty?' }
   end
 
   test 'should destroy empty albums for moderator' do
@@ -279,6 +282,7 @@ class AlbumsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'album_policy', 'type' => 'forbidden', 'action' => 'merge?' }
   end
 
   test 'should merge albums for moderator' do
diff --git a/test/controllers/artists_controller_test.rb b/test/controllers/artists_controller_test.rb
index db61ad99..7eb3c270 100644
--- a/test/controllers/artists_controller_test.rb
+++ b/test/controllers/artists_controller_test.rb
@@ -39,6 +39,7 @@ class ArtistsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'artist_policy', 'type' => 'forbidden', 'action' => 'create?' }
   end
 
   test 'should create artist for moderator' do
@@ -176,6 +177,7 @@ class ArtistsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'artist_policy', 'type' => 'forbidden', 'action' => 'destroy?' }
   end
 
   test 'should destroy artist for moderator' do
@@ -198,6 +200,7 @@ class ArtistsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'artist_policy', 'type' => 'forbidden', 'action' => 'destroy_empty?' }
   end
 
   test 'should destroy empty artists for moderator (track_artist)' do
@@ -248,6 +251,7 @@ class ArtistsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'artist_policy', 'type' => 'forbidden', 'action' => 'merge?' }
   end
 
   test 'should merge artists for moderator' do
diff --git a/test/controllers/auth_tokens_controller_test.rb b/test/controllers/auth_tokens_controller_test.rb
index 95a0e410..7456ba71 100644
--- a/test/controllers/auth_tokens_controller_test.rb
+++ b/test/controllers/auth_tokens_controller_test.rb
@@ -63,6 +63,7 @@ class AuthTokensControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unauthorized
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'base', 'type' => 'wrong_credentials' }
   end
 
   test 'should not create auth_token without user_agent' do
diff --git a/test/controllers/codec_conversions_controller_test.rb b/test/controllers/codec_conversions_controller_test.rb
index e68ce2c4..62ee6ad6 100644
--- a/test/controllers/codec_conversions_controller_test.rb
+++ b/test/controllers/codec_conversions_controller_test.rb
@@ -52,6 +52,7 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'codec_conversion_policy', 'type' => 'forbidden', 'action' => 'create?' }
   end
 
   test 'should create codec_conversion for moderator' do
@@ -164,6 +165,7 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
     } }
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'codec_conversion_policy', 'type' => 'forbidden', 'action' => 'update?' }
   end
 
   test 'should update codec_conversion for moderator' do
@@ -205,6 +207,7 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'codec_conversion_policy', 'type' => 'forbidden', 'action' => 'destroy?' }
   end
 
   test 'should destroy codec_conversion for moderator' do
diff --git a/test/controllers/codecs_controller_test.rb b/test/controllers/codecs_controller_test.rb
index 1769cc59..b636a072 100644
--- a/test/controllers/codecs_controller_test.rb
+++ b/test/controllers/codecs_controller_test.rb
@@ -40,6 +40,7 @@ class CodecsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'codec_policy', 'type' => 'forbidden', 'action' => 'create?' }
   end
 
   test 'should not create codec with missing extension' do
@@ -95,6 +96,7 @@ class CodecsControllerTest < ActionDispatch::IntegrationTest
     patch codec_url(@codec), params: { codec: { mimetype: @codec.mimetype } }
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'codec_policy', 'type' => 'forbidden', 'action' => 'update?' }
   end
 
   test 'should not update codec when clearing mimetype' do
@@ -128,6 +130,7 @@ class CodecsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'codec_policy', 'type' => 'forbidden', 'action' => 'destroy?' }
   end
 
   test 'should destroy codec for moderator' do
diff --git a/test/controllers/cover_filenames_controller_test.rb b/test/controllers/cover_filenames_controller_test.rb
index 37fee62d..51da2a42 100644
--- a/test/controllers/cover_filenames_controller_test.rb
+++ b/test/controllers/cover_filenames_controller_test.rb
@@ -10,6 +10,7 @@ class CoverFilenamesControllerTest < ActionDispatch::IntegrationTest
     get cover_filenames_url
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'cover_filename_policy', 'type' => 'forbidden', 'action' => 'index?' }
   end
 
   test 'should get index for moderator' do
@@ -59,6 +60,7 @@ class CoverFilenamesControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'cover_filename_policy', 'type' => 'forbidden', 'action' => 'create?' }
   end
 
   test 'should not create cover_filename with empty filename' do
@@ -95,6 +97,7 @@ class CoverFilenamesControllerTest < ActionDispatch::IntegrationTest
     get cover_filename_url(@cover_filename)
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'cover_filename_policy', 'type' => 'forbidden', 'action' => 'show?' }
   end
 
   test 'should show cover_filename for moderator' do
@@ -117,6 +120,7 @@ class CoverFilenamesControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'cover_filename_policy', 'type' => 'forbidden', 'action' => 'destroy?' }
   end
 
   test 'should destroy cover_filename for moderator' do
diff --git a/test/controllers/genres_controller_test.rb b/test/controllers/genres_controller_test.rb
index ee744108..09be283d 100644
--- a/test/controllers/genres_controller_test.rb
+++ b/test/controllers/genres_controller_test.rb
@@ -40,6 +40,7 @@ class GenresControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'genre_policy', 'type' => 'forbidden', 'action' => 'create?' }
   end
 
   test 'should not create genre with empty name' do
@@ -82,6 +83,7 @@ class GenresControllerTest < ActionDispatch::IntegrationTest
     patch genre_url(@genre), params: { genre: { name: @genre.name } }
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'genre_policy', 'type' => 'forbidden', 'action' => 'update?' }
   end
 
   test 'should not update genre to empty name' do
@@ -113,6 +115,7 @@ class GenresControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'genre_policy', 'type' => 'forbidden', 'action' => 'destroy?' }
   end
 
   test 'should destroy genre for moderator' do
@@ -139,6 +142,7 @@ class GenresControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'genre_policy', 'type' => 'forbidden', 'action' => 'destroy_empty?' }
   end
 
   test 'should destroy empty genres for moderator' do
@@ -179,6 +183,7 @@ class GenresControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'genre_policy', 'type' => 'forbidden', 'action' => 'merge?' }
   end
 
   test 'should merge genres for moderator' do
diff --git a/test/controllers/image_types_controller_test.rb b/test/controllers/image_types_controller_test.rb
index 098ec72b..430bdb48 100644
--- a/test/controllers/image_types_controller_test.rb
+++ b/test/controllers/image_types_controller_test.rb
@@ -40,6 +40,7 @@ class ImageTypesControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'image_type_policy', 'type' => 'forbidden', 'action' => 'create?' }
   end
 
   test 'should not create image_type without extension' do
@@ -94,6 +95,7 @@ class ImageTypesControllerTest < ActionDispatch::IntegrationTest
     patch image_type_url(@image_type), params: { image_type: { mimetype: @image_type.mimetype } }
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'image_type_policy', 'type' => 'forbidden', 'action' => 'update?' }
   end
 
   test 'should not update image_type to empty mimetype' do
@@ -125,6 +127,7 @@ class ImageTypesControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'image_type_policy', 'type' => 'forbidden', 'action' => 'destroy?' }
   end
 
   test 'should destroy image_type for moderator' do
diff --git a/test/controllers/labels_controller_test.rb b/test/controllers/labels_controller_test.rb
index 87280c96..b95e5d83 100644
--- a/test/controllers/labels_controller_test.rb
+++ b/test/controllers/labels_controller_test.rb
@@ -40,6 +40,7 @@ class LabelsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'label_policy', 'type' => 'forbidden', 'action' => 'create?' }
   end
 
   test 'should not create label with empty name' do
@@ -83,6 +84,7 @@ class LabelsControllerTest < ActionDispatch::IntegrationTest
     patch label_url(@label), params: { label: { name: @label.name } }
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'label_policy', 'type' => 'forbidden', 'action' => 'update?' }
   end
 
   test 'should not update label to empty name' do
@@ -114,6 +116,7 @@ class LabelsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'label_policy', 'type' => 'forbidden', 'action' => 'destroy?' }
   end
 
   test 'should destroy label for moderator' do
@@ -140,6 +143,7 @@ class LabelsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'label_policy', 'type' => 'forbidden', 'action' => 'destroy_empty?' }
   end
 
   test 'should destroy empty labels for moderator' do
@@ -180,6 +184,7 @@ class LabelsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'label_policy', 'type' => 'forbidden', 'action' => 'merge?' }
   end
 
   test 'should merge labels for moderator' do
diff --git a/test/controllers/locations_controller_test.rb b/test/controllers/locations_controller_test.rb
index b1e86d72..c1c8dd65 100644
--- a/test/controllers/locations_controller_test.rb
+++ b/test/controllers/locations_controller_test.rb
@@ -10,6 +10,7 @@ class LocationsControllerTest < ActionDispatch::IntegrationTest
     get locations_url
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'location_policy', 'type' => 'forbidden', 'action' => 'index?' }
   end
 
   test 'should get index for moderator' do
@@ -59,6 +60,7 @@ class LocationsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'location_policy', 'type' => 'forbidden', 'action' => 'create?' }
   end
 
   test 'should not create location with empty path' do
@@ -95,6 +97,7 @@ class LocationsControllerTest < ActionDispatch::IntegrationTest
     get location_url(@location)
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'location_policy', 'type' => 'forbidden', 'action' => 'show?' }
   end
 
   test 'should show location for moderator' do
@@ -117,6 +120,7 @@ class LocationsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'location_policy', 'type' => 'forbidden', 'action' => 'destroy?' }
   end
 
   test 'should destroy location for moderator' do
diff --git a/test/controllers/playlists_controller_test.rb b/test/controllers/playlists_controller_test.rb
index aec8011e..f0576c9b 100644
--- a/test/controllers/playlists_controller_test.rb
+++ b/test/controllers/playlists_controller_test.rb
@@ -125,6 +125,7 @@ class PlaylistsControllerTest < ActionDispatch::IntegrationTest
     patch playlist_url(@playlist), params: { playlist: { name: 'My playlist' } }
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'playlist_policy', 'type' => 'forbidden', 'action' => 'update?' }
   end
 
   test 'should not update secret playlist for different user' do
@@ -133,6 +134,7 @@ class PlaylistsControllerTest < ActionDispatch::IntegrationTest
     patch playlist_url(@playlist), params: { playlist: { name: 'My playlist' } }
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'playlist_policy', 'type' => 'forbidden', 'action' => 'update?' }
   end
 
   test 'should destroy shared playlist for user' do
@@ -151,6 +153,7 @@ class PlaylistsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'playlist_policy', 'type' => 'forbidden', 'action' => 'destroy?' }
   end
 
   test 'should not destroy secret playlist for different user' do
@@ -161,6 +164,7 @@ class PlaylistsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'playlist_policy', 'type' => 'forbidden', 'action' => 'destroy?' }
   end
 
   test 'should not add item if no user' do
@@ -173,6 +177,7 @@ class PlaylistsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unauthorized
+    assert_includes response.parsed_body['errors'], { 'policy' => 'playlist_policy', 'type' => 'unauthorized', 'action' => 'add_item?' }
   end
 
   test 'should add item in shared playlist' do
@@ -208,5 +213,6 @@ class PlaylistsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'playlist_policy', 'type' => 'forbidden', 'action' => 'add_item?' }
   end
 end
diff --git a/test/controllers/rescans_controller_test.rb b/test/controllers/rescans_controller_test.rb
index 50d21ca8..9a6688dd 100644
--- a/test/controllers/rescans_controller_test.rb
+++ b/test/controllers/rescans_controller_test.rb
@@ -12,6 +12,7 @@ class RescansControllerTest < ActionDispatch::IntegrationTest
     get rescans_url
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'rescan_runner_policy', 'type' => 'forbidden', 'action' => 'index?' }
   end
 
   test 'should get index for moderator' do
@@ -58,6 +59,7 @@ class RescansControllerTest < ActionDispatch::IntegrationTest
     get rescan_url(@runner)
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'rescan_runner_policy', 'type' => 'forbidden', 'action' => 'show?' }
   end
 
   test 'should get show for moderator' do
@@ -71,6 +73,7 @@ class RescansControllerTest < ActionDispatch::IntegrationTest
     post rescan_url(@runner)
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'rescan_runner_policy', 'type' => 'forbidden', 'action' => 'start?' }
   end
 
   test 'should start rescan' do
@@ -91,6 +94,7 @@ class RescansControllerTest < ActionDispatch::IntegrationTest
     post rescans_url
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'rescan_runner_policy', 'type' => 'forbidden', 'action' => 'start_all?' }
   end
 
   test 'should start all rescans' do
diff --git a/test/controllers/tracks_controller_test.rb b/test/controllers/tracks_controller_test.rb
index 0d90a7f2..d131c8ca 100644
--- a/test/controllers/tracks_controller_test.rb
+++ b/test/controllers/tracks_controller_test.rb
@@ -63,6 +63,7 @@ class TracksControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'track_policy', 'type' => 'forbidden', 'action' => 'create?' }
   end
 
   test 'should not create track without title' do
@@ -188,6 +189,7 @@ class TracksControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'track_policy', 'type' => 'forbidden', 'action' => 'destroy?' }
   end
 
   test 'should destroy track for moderator' do
@@ -206,6 +208,7 @@ class TracksControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'track_policy', 'type' => 'forbidden', 'action' => 'destroy_empty?' }
   end
 
   test 'should destroy empty tracks for moderator' do
@@ -232,6 +235,7 @@ class TracksControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'track_policy', 'type' => 'forbidden', 'action' => 'merge?' }
   end
 
   test 'should merge tracks for moderator' do
@@ -257,6 +261,7 @@ class TracksControllerTest < ActionDispatch::IntegrationTest
     get audio_track_url(create(:track))
 
     assert_response :not_found
+    assert_includes response.parsed_body['errors'], { 'model' => 'audio', 'type' => 'not_found' }
   end
 
   test 'should return not_found and destroy audio if file is missing ' do
@@ -267,6 +272,7 @@ class TracksControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :not_found
+    assert_includes response.parsed_body['errors'], { 'model' => 'audio', 'type' => 'not_found' }
   end
 
   test 'should serve audio to user' do
@@ -307,6 +313,7 @@ class TracksControllerAudioTest < ActionDispatch::IntegrationTest
       get audio_track_url(track, codec_conversion_id: 0)
 
       assert_response :not_found
+      assert_includes response.parsed_body['errors'], { 'model' => 'codec_conversion', 'type' => 'not_found' }
     end
 
     test 'should create transcoded_item if codec_conversion is present' do
diff --git a/test/controllers/users_controller_test.rb b/test/controllers/users_controller_test.rb
index c0c2bcf9..84bb7527 100644
--- a/test/controllers/users_controller_test.rb
+++ b/test/controllers/users_controller_test.rb
@@ -40,6 +40,7 @@ class UsersControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :forbidden
+    assert_includes response.parsed_body['errors'], { 'policy' => 'user_policy', 'type' => 'forbidden', 'action' => 'create?' }
   end
 
   test 'should not create user without name' do
@@ -79,6 +80,7 @@ class UsersControllerTest < ActionDispatch::IntegrationTest
     patch user_url(@user), params: { user: { password: 'new password', current_password: 'not correct' } }
 
     assert_response :unauthorized
+    assert_includes response.parsed_body['errors'], { 'attribute' => 'base', 'type' => 'incorrect_password' }
   end
 
   test 'should update password with current password for current user' do

From c766af8cdbc24de70af402edce5cf63af8d4324f Mon Sep 17 00:00:00 2001
From: Robbe Van Petegem <git@robbevp.be>
Date: Sat, 25 Jul 2026 12:08:15 +0200
Subject: [PATCH 3/7] Include `model` key in error messages

---
 app/controllers/application_controller.rb             |  6 +++---
 app/controllers/auth_tokens_controller.rb             |  2 +-
 app/controllers/users_controller.rb                   |  2 +-
 test/controllers/albums_controller_test.rb            |  4 ++--
 test/controllers/artists_controller_test.rb           |  4 ++--
 test/controllers/auth_tokens_controller_test.rb       |  4 ++--
 test/controllers/codec_conversions_controller_test.rb | 10 +++++-----
 test/controllers/codecs_controller_test.rb            |  6 +++---
 test/controllers/cover_filenames_controller_test.rb   |  2 +-
 test/controllers/genres_controller_test.rb            |  4 ++--
 test/controllers/image_types_controller_test.rb       |  6 +++---
 test/controllers/labels_controller_test.rb            |  4 ++--
 test/controllers/locations_controller_test.rb         |  2 +-
 test/controllers/playlists_controller_test.rb         |  4 ++--
 test/controllers/plays_controller_test.rb             |  2 +-
 test/controllers/tracks_controller_test.rb            |  6 +++---
 test/controllers/users_controller_test.rb             |  6 +++---
 17 files changed, 37 insertions(+), 37 deletions(-)

diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 99a0a963..6dbf7eaa 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -45,13 +45,13 @@ def stale?(scope:, **)
     super(etag:, **)
   end
 
-  def transform_error_for_json(error)
-    { attribute: error.attribute, type: ERROR_TYPE_MAP[error.type] }
+  def transform_error_for_json(object, error)
+    { model: object.model_name.singular, attribute: error.attribute, type: ERROR_TYPE_MAP[error.type] }
   end
 
   # This method expects an instance of a class that includes `ActiveModel::Errors`
   def transform_errors_for_json(object)
-    { errors: object.errors.errors.map { transform_error_for_json(it) } }
+    { errors: object.errors.errors.map { transform_error_for_json(object, it) } }
   end
 
   private
diff --git a/app/controllers/auth_tokens_controller.rb b/app/controllers/auth_tokens_controller.rb
index f646ec8d..b5b2aef7 100644
--- a/app/controllers/auth_tokens_controller.rb
+++ b/app/controllers/auth_tokens_controller.rb
@@ -19,7 +19,7 @@ def create
 
     user = User.find_by(name: params[:name])
     unless user.try(:authenticate, params[:password])
-      render json: { errors: [{ attribute: :base, type: :wrong_credentials }] }, status: :unauthorized
+      render json: { errors: [{ model: :auth_token, attribute: :base, type: :wrong_credentials }] }, status: :unauthorized
       return
     end
 
diff --git a/app/controllers/users_controller.rb b/app/controllers/users_controller.rb
index df5efbdd..4b9822e3 100644
--- a/app/controllers/users_controller.rb
+++ b/app/controllers/users_controller.rb
@@ -29,7 +29,7 @@ def update
     if @user == current_user &&
        params[:user][:password].present? &&
        !@user.try(:authenticate, params[:user][:current_password])
-      render json: { errors: [{ attribute: :base, type: :incorrect_password }] }, status: :unauthorized
+      render json: { errors: [{ model: :user, attribute: :base, type: :incorrect_password }] }, status: :unauthorized
       return
     end
 
diff --git a/test/controllers/albums_controller_test.rb b/test/controllers/albums_controller_test.rb
index 8c4b94eb..b50ff190 100644
--- a/test/controllers/albums_controller_test.rb
+++ b/test/controllers/albums_controller_test.rb
@@ -75,7 +75,7 @@ class AlbumsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'title', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'album', 'attribute' => 'title', 'type' => 'required' }
   end
 
   test 'should create dependent album_labels' do
@@ -156,7 +156,7 @@ class AlbumsControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :unprocessable_content
     assert_not_equal '', @album.reload.title
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'title', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'album', 'attribute' => 'title', 'type' => 'required' }
   end
 
   test 'should clear review comment' do
diff --git a/test/controllers/artists_controller_test.rb b/test/controllers/artists_controller_test.rb
index 7eb3c270..fe5b12e8 100644
--- a/test/controllers/artists_controller_test.rb
+++ b/test/controllers/artists_controller_test.rb
@@ -70,7 +70,7 @@ class ArtistsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'artist', 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should show artist' do
@@ -94,7 +94,7 @@ class ArtistsControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :unprocessable_content
     assert_not_equal '', @artist.reload.name
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'artist', 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should not update artist metadata for user' do
diff --git a/test/controllers/auth_tokens_controller_test.rb b/test/controllers/auth_tokens_controller_test.rb
index 7456ba71..79698a84 100644
--- a/test/controllers/auth_tokens_controller_test.rb
+++ b/test/controllers/auth_tokens_controller_test.rb
@@ -63,7 +63,7 @@ class AuthTokensControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unauthorized
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'base', 'type' => 'wrong_credentials' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'auth_token', 'attribute' => 'base', 'type' => 'wrong_credentials' }
   end
 
   test 'should not create auth_token without user_agent' do
@@ -75,7 +75,7 @@ class AuthTokensControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'user_agent', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'auth_token', 'attribute' => 'user_agent', 'type' => 'required' }
   end
 
   test 'should show auth_token' do
diff --git a/test/controllers/codec_conversions_controller_test.rb b/test/controllers/codec_conversions_controller_test.rb
index 62ee6ad6..c3f76960 100644
--- a/test/controllers/codec_conversions_controller_test.rb
+++ b/test/controllers/codec_conversions_controller_test.rb
@@ -91,7 +91,7 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'not_unique' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'codec_conversion', 'attribute' => 'name', 'type' => 'not_unique' }
   end
 
   test 'should not create codec_conversion with empty ffmpeg_params' do
@@ -105,7 +105,7 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'ffmpeg_params', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'codec_conversion', 'attribute' => 'ffmpeg_params', 'type' => 'required' }
   end
 
   test 'should not create codec_conversion with empty name' do
@@ -119,7 +119,7 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'codec_conversion', 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should not create codec_conversion with non-existing resulting_codec' do
@@ -134,7 +134,7 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'resulting_codec', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'codec_conversion', 'attribute' => 'resulting_codec', 'type' => 'required' }
   end
 
   test 'should create codec_conversion for admin' do
@@ -187,7 +187,7 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'codec_conversion', 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should update codec_conversion for admin' do
diff --git a/test/controllers/codecs_controller_test.rb b/test/controllers/codecs_controller_test.rb
index b636a072..694955b4 100644
--- a/test/controllers/codecs_controller_test.rb
+++ b/test/controllers/codecs_controller_test.rb
@@ -51,7 +51,7 @@ class CodecsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'extension', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'codec', 'attribute' => 'extension', 'type' => 'required' }
   end
 
   test 'should not create codec with missing mimetype' do
@@ -63,7 +63,7 @@ class CodecsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'mimetype', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'codec', 'attribute' => 'mimetype', 'type' => 'required' }
   end
 
   test 'should create codec for moderator' do
@@ -107,7 +107,7 @@ class CodecsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'mimetype', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'codec', 'attribute' => 'mimetype', 'type' => 'required' }
   end
 
   test 'should update codec for moderator' do
diff --git a/test/controllers/cover_filenames_controller_test.rb b/test/controllers/cover_filenames_controller_test.rb
index 51da2a42..535a488d 100644
--- a/test/controllers/cover_filenames_controller_test.rb
+++ b/test/controllers/cover_filenames_controller_test.rb
@@ -70,7 +70,7 @@ class CoverFilenamesControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'filename', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'cover_filename', 'attribute' => 'filename', 'type' => 'required' }
   end
 
   test 'should create cover_filename for moderator' do
diff --git a/test/controllers/genres_controller_test.rb b/test/controllers/genres_controller_test.rb
index 09be283d..f5ec82ef 100644
--- a/test/controllers/genres_controller_test.rb
+++ b/test/controllers/genres_controller_test.rb
@@ -50,7 +50,7 @@ class GenresControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'genre', 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should create genre for moderator' do
@@ -92,7 +92,7 @@ class GenresControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :unprocessable_content
     assert_not_equal '', @genre.reload.name
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'genre', 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should update genre for moderator' do
diff --git a/test/controllers/image_types_controller_test.rb b/test/controllers/image_types_controller_test.rb
index 430bdb48..87f196bf 100644
--- a/test/controllers/image_types_controller_test.rb
+++ b/test/controllers/image_types_controller_test.rb
@@ -51,7 +51,7 @@ class ImageTypesControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'extension', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'image_type', 'attribute' => 'extension', 'type' => 'required' }
   end
 
   test 'should not create image_type without mimetype' do
@@ -62,7 +62,7 @@ class ImageTypesControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'mimetype', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'image_type', 'attribute' => 'mimetype', 'type' => 'required' }
   end
 
   test 'should create image_type for moderator' do
@@ -104,7 +104,7 @@ class ImageTypesControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :unprocessable_content
     assert_not_equal '', @image_type.reload.mimetype
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'mimetype', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'image_type', 'attribute' => 'mimetype', 'type' => 'required' }
   end
 
   test 'should update image_type for moderator' do
diff --git a/test/controllers/labels_controller_test.rb b/test/controllers/labels_controller_test.rb
index b95e5d83..3e26cc97 100644
--- a/test/controllers/labels_controller_test.rb
+++ b/test/controllers/labels_controller_test.rb
@@ -51,7 +51,7 @@ class LabelsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'label', 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should create label for moderator' do
@@ -93,7 +93,7 @@ class LabelsControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :unprocessable_content
     assert_not_equal '', @label.reload.name
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'label', 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should update label for moderator' do
diff --git a/test/controllers/locations_controller_test.rb b/test/controllers/locations_controller_test.rb
index c1c8dd65..8f7c1d6d 100644
--- a/test/controllers/locations_controller_test.rb
+++ b/test/controllers/locations_controller_test.rb
@@ -70,7 +70,7 @@ class LocationsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'path', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'location', 'attribute' => 'path', 'type' => 'required' }
   end
 
   test 'should create location for moderator' do
diff --git a/test/controllers/playlists_controller_test.rb b/test/controllers/playlists_controller_test.rb
index f0576c9b..ae148103 100644
--- a/test/controllers/playlists_controller_test.rb
+++ b/test/controllers/playlists_controller_test.rb
@@ -66,7 +66,7 @@ class PlaylistsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'playlist', 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should create personal playlist for current user if specified' do
@@ -103,7 +103,7 @@ class PlaylistsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'playlist', 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should create playlist items during update' do
diff --git a/test/controllers/plays_controller_test.rb b/test/controllers/plays_controller_test.rb
index 93f90827..9e70c240 100644
--- a/test/controllers/plays_controller_test.rb
+++ b/test/controllers/plays_controller_test.rb
@@ -75,7 +75,7 @@ class PlaysControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'played_at', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'play', 'attribute' => 'played_at', 'type' => 'required' }
   end
 
   test 'should get stats and  not return play stats for other users' do
diff --git a/test/controllers/tracks_controller_test.rb b/test/controllers/tracks_controller_test.rb
index d131c8ca..8a6f4b0b 100644
--- a/test/controllers/tracks_controller_test.rb
+++ b/test/controllers/tracks_controller_test.rb
@@ -73,7 +73,7 @@ class TracksControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'title', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'track', 'attribute' => 'title', 'type' => 'required' }
   end
 
   test 'should not create track without album_id' do
@@ -83,7 +83,7 @@ class TracksControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'album', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'track', 'attribute' => 'album', 'type' => 'required' }
   end
 
   test 'should create track for moderator' do
@@ -160,7 +160,7 @@ class TracksControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :unprocessable_content
     assert_not_equal '', @track.reload.title
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'title', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'track', 'attribute' => 'title', 'type' => 'required' }
   end
 
   test 'should clear review comment' do
diff --git a/test/controllers/users_controller_test.rb b/test/controllers/users_controller_test.rb
index 84bb7527..4cae79f3 100644
--- a/test/controllers/users_controller_test.rb
+++ b/test/controllers/users_controller_test.rb
@@ -51,7 +51,7 @@ class UsersControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'user', 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should create user for admin' do
@@ -80,7 +80,7 @@ class UsersControllerTest < ActionDispatch::IntegrationTest
     patch user_url(@user), params: { user: { password: 'new password', current_password: 'not correct' } }
 
     assert_response :unauthorized
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'base', 'type' => 'incorrect_password' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'user', 'attribute' => 'base', 'type' => 'incorrect_password' }
   end
 
   test 'should update password with current password for current user' do
@@ -102,7 +102,7 @@ class UsersControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :unprocessable_content
     assert_not_equal '', @user.reload.name
-    assert_includes response.parsed_body['errors'], { 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'user', 'attribute' => 'name', 'type' => 'required' }
   end
 
   test 'should not update own permission if not admin' do

From ac6a0e5045e4d476e36f0c3595391831ad3ea261 Mon Sep 17 00:00:00 2001
From: Robbe Van Petegem <git@robbevp.be>
Date: Sat, 25 Jul 2026 12:09:05 +0200
Subject: [PATCH 4/7] Rename error types to make conversion in web easier

---
 app/controllers/application_controller.rb             |  2 +-
 test/controllers/albums_controller_test.rb            |  4 ++--
 test/controllers/artists_controller_test.rb           |  4 ++--
 test/controllers/auth_tokens_controller_test.rb       |  2 +-
 test/controllers/codec_conversions_controller_test.rb | 10 +++++-----
 test/controllers/codecs_controller_test.rb            |  6 +++---
 test/controllers/cover_filenames_controller_test.rb   |  2 +-
 test/controllers/genres_controller_test.rb            |  4 ++--
 test/controllers/image_types_controller_test.rb       |  6 +++---
 test/controllers/labels_controller_test.rb            |  4 ++--
 test/controllers/locations_controller_test.rb         |  2 +-
 test/controllers/playlists_controller_test.rb         |  4 ++--
 test/controllers/plays_controller_test.rb             |  2 +-
 test/controllers/tracks_controller_test.rb            |  6 +++---
 test/controllers/users_controller_test.rb             |  4 ++--
 15 files changed, 31 insertions(+), 31 deletions(-)

diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 6dbf7eaa..53b2e841 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -3,7 +3,7 @@ class ApplicationController < ActionController::API
   include ActionController::HttpAuthentication::Token::ControllerMethods
 
   # This map only includes the type of validation errors that we could have inside the app
-  ERROR_TYPE_MAP = { blank: :required, taken: :not_unique }.freeze
+  ERROR_TYPE_MAP = { blank: :blank, taken: :taken }.freeze
 
   etag { params[:page] }
   etag { params[:per_page] }
diff --git a/test/controllers/albums_controller_test.rb b/test/controllers/albums_controller_test.rb
index b50ff190..4bba4c89 100644
--- a/test/controllers/albums_controller_test.rb
+++ b/test/controllers/albums_controller_test.rb
@@ -75,7 +75,7 @@ class AlbumsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'album', 'attribute' => 'title', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'album', 'attribute' => 'title', 'type' => 'blank' }
   end
 
   test 'should create dependent album_labels' do
@@ -156,7 +156,7 @@ class AlbumsControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :unprocessable_content
     assert_not_equal '', @album.reload.title
-    assert_includes response.parsed_body['errors'], { 'model' => 'album', 'attribute' => 'title', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'album', 'attribute' => 'title', 'type' => 'blank' }
   end
 
   test 'should clear review comment' do
diff --git a/test/controllers/artists_controller_test.rb b/test/controllers/artists_controller_test.rb
index fe5b12e8..f9107e24 100644
--- a/test/controllers/artists_controller_test.rb
+++ b/test/controllers/artists_controller_test.rb
@@ -70,7 +70,7 @@ class ArtistsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'artist', 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'artist', 'attribute' => 'name', 'type' => 'blank' }
   end
 
   test 'should show artist' do
@@ -94,7 +94,7 @@ class ArtistsControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :unprocessable_content
     assert_not_equal '', @artist.reload.name
-    assert_includes response.parsed_body['errors'], { 'model' => 'artist', 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'artist', 'attribute' => 'name', 'type' => 'blank' }
   end
 
   test 'should not update artist metadata for user' do
diff --git a/test/controllers/auth_tokens_controller_test.rb b/test/controllers/auth_tokens_controller_test.rb
index 79698a84..af68615a 100644
--- a/test/controllers/auth_tokens_controller_test.rb
+++ b/test/controllers/auth_tokens_controller_test.rb
@@ -75,7 +75,7 @@ class AuthTokensControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'auth_token', 'attribute' => 'user_agent', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'auth_token', 'attribute' => 'user_agent', 'type' => 'blank' }
   end
 
   test 'should show auth_token' do
diff --git a/test/controllers/codec_conversions_controller_test.rb b/test/controllers/codec_conversions_controller_test.rb
index c3f76960..12dfeec0 100644
--- a/test/controllers/codec_conversions_controller_test.rb
+++ b/test/controllers/codec_conversions_controller_test.rb
@@ -91,7 +91,7 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'codec_conversion', 'attribute' => 'name', 'type' => 'not_unique' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'codec_conversion', 'attribute' => 'name', 'type' => 'taken' }
   end
 
   test 'should not create codec_conversion with empty ffmpeg_params' do
@@ -105,7 +105,7 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'codec_conversion', 'attribute' => 'ffmpeg_params', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'codec_conversion', 'attribute' => 'ffmpeg_params', 'type' => 'blank' }
   end
 
   test 'should not create codec_conversion with empty name' do
@@ -119,7 +119,7 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'codec_conversion', 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'codec_conversion', 'attribute' => 'name', 'type' => 'blank' }
   end
 
   test 'should not create codec_conversion with non-existing resulting_codec' do
@@ -134,7 +134,7 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'codec_conversion', 'attribute' => 'resulting_codec', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'codec_conversion', 'attribute' => 'resulting_codec', 'type' => 'blank' }
   end
 
   test 'should create codec_conversion for admin' do
@@ -187,7 +187,7 @@ class CodecConversionsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'codec_conversion', 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'codec_conversion', 'attribute' => 'name', 'type' => 'blank' }
   end
 
   test 'should update codec_conversion for admin' do
diff --git a/test/controllers/codecs_controller_test.rb b/test/controllers/codecs_controller_test.rb
index 694955b4..ea3d0806 100644
--- a/test/controllers/codecs_controller_test.rb
+++ b/test/controllers/codecs_controller_test.rb
@@ -51,7 +51,7 @@ class CodecsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'codec', 'attribute' => 'extension', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'codec', 'attribute' => 'extension', 'type' => 'blank' }
   end
 
   test 'should not create codec with missing mimetype' do
@@ -63,7 +63,7 @@ class CodecsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'codec', 'attribute' => 'mimetype', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'codec', 'attribute' => 'mimetype', 'type' => 'blank' }
   end
 
   test 'should create codec for moderator' do
@@ -107,7 +107,7 @@ class CodecsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'codec', 'attribute' => 'mimetype', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'codec', 'attribute' => 'mimetype', 'type' => 'blank' }
   end
 
   test 'should update codec for moderator' do
diff --git a/test/controllers/cover_filenames_controller_test.rb b/test/controllers/cover_filenames_controller_test.rb
index 535a488d..8d770236 100644
--- a/test/controllers/cover_filenames_controller_test.rb
+++ b/test/controllers/cover_filenames_controller_test.rb
@@ -70,7 +70,7 @@ class CoverFilenamesControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'cover_filename', 'attribute' => 'filename', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'cover_filename', 'attribute' => 'filename', 'type' => 'blank' }
   end
 
   test 'should create cover_filename for moderator' do
diff --git a/test/controllers/genres_controller_test.rb b/test/controllers/genres_controller_test.rb
index f5ec82ef..c6a71dae 100644
--- a/test/controllers/genres_controller_test.rb
+++ b/test/controllers/genres_controller_test.rb
@@ -50,7 +50,7 @@ class GenresControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'genre', 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'genre', 'attribute' => 'name', 'type' => 'blank' }
   end
 
   test 'should create genre for moderator' do
@@ -92,7 +92,7 @@ class GenresControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :unprocessable_content
     assert_not_equal '', @genre.reload.name
-    assert_includes response.parsed_body['errors'], { 'model' => 'genre', 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'genre', 'attribute' => 'name', 'type' => 'blank' }
   end
 
   test 'should update genre for moderator' do
diff --git a/test/controllers/image_types_controller_test.rb b/test/controllers/image_types_controller_test.rb
index 87f196bf..88b87b23 100644
--- a/test/controllers/image_types_controller_test.rb
+++ b/test/controllers/image_types_controller_test.rb
@@ -51,7 +51,7 @@ class ImageTypesControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'image_type', 'attribute' => 'extension', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'image_type', 'attribute' => 'extension', 'type' => 'blank' }
   end
 
   test 'should not create image_type without mimetype' do
@@ -62,7 +62,7 @@ class ImageTypesControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'image_type', 'attribute' => 'mimetype', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'image_type', 'attribute' => 'mimetype', 'type' => 'blank' }
   end
 
   test 'should create image_type for moderator' do
@@ -104,7 +104,7 @@ class ImageTypesControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :unprocessable_content
     assert_not_equal '', @image_type.reload.mimetype
-    assert_includes response.parsed_body['errors'], { 'model' => 'image_type', 'attribute' => 'mimetype', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'image_type', 'attribute' => 'mimetype', 'type' => 'blank' }
   end
 
   test 'should update image_type for moderator' do
diff --git a/test/controllers/labels_controller_test.rb b/test/controllers/labels_controller_test.rb
index 3e26cc97..4312c644 100644
--- a/test/controllers/labels_controller_test.rb
+++ b/test/controllers/labels_controller_test.rb
@@ -51,7 +51,7 @@ class LabelsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'label', 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'label', 'attribute' => 'name', 'type' => 'blank' }
   end
 
   test 'should create label for moderator' do
@@ -93,7 +93,7 @@ class LabelsControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :unprocessable_content
     assert_not_equal '', @label.reload.name
-    assert_includes response.parsed_body['errors'], { 'model' => 'label', 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'label', 'attribute' => 'name', 'type' => 'blank' }
   end
 
   test 'should update label for moderator' do
diff --git a/test/controllers/locations_controller_test.rb b/test/controllers/locations_controller_test.rb
index 8f7c1d6d..1df033d6 100644
--- a/test/controllers/locations_controller_test.rb
+++ b/test/controllers/locations_controller_test.rb
@@ -70,7 +70,7 @@ class LocationsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'location', 'attribute' => 'path', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'location', 'attribute' => 'path', 'type' => 'blank' }
   end
 
   test 'should create location for moderator' do
diff --git a/test/controllers/playlists_controller_test.rb b/test/controllers/playlists_controller_test.rb
index ae148103..a6806a07 100644
--- a/test/controllers/playlists_controller_test.rb
+++ b/test/controllers/playlists_controller_test.rb
@@ -66,7 +66,7 @@ class PlaylistsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'playlist', 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'playlist', 'attribute' => 'name', 'type' => 'blank' }
   end
 
   test 'should create personal playlist for current user if specified' do
@@ -103,7 +103,7 @@ class PlaylistsControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'playlist', 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'playlist', 'attribute' => 'name', 'type' => 'blank' }
   end
 
   test 'should create playlist items during update' do
diff --git a/test/controllers/plays_controller_test.rb b/test/controllers/plays_controller_test.rb
index 9e70c240..ebaf4a4e 100644
--- a/test/controllers/plays_controller_test.rb
+++ b/test/controllers/plays_controller_test.rb
@@ -75,7 +75,7 @@ class PlaysControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'play', 'attribute' => 'played_at', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'play', 'attribute' => 'played_at', 'type' => 'blank' }
   end
 
   test 'should get stats and  not return play stats for other users' do
diff --git a/test/controllers/tracks_controller_test.rb b/test/controllers/tracks_controller_test.rb
index 8a6f4b0b..b3876151 100644
--- a/test/controllers/tracks_controller_test.rb
+++ b/test/controllers/tracks_controller_test.rb
@@ -73,7 +73,7 @@ class TracksControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'track', 'attribute' => 'title', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'track', 'attribute' => 'title', 'type' => 'blank' }
   end
 
   test 'should not create track without album_id' do
@@ -83,7 +83,7 @@ class TracksControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'track', 'attribute' => 'album', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'track', 'attribute' => 'album', 'type' => 'blank' }
   end
 
   test 'should create track for moderator' do
@@ -160,7 +160,7 @@ class TracksControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :unprocessable_content
     assert_not_equal '', @track.reload.title
-    assert_includes response.parsed_body['errors'], { 'model' => 'track', 'attribute' => 'title', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'track', 'attribute' => 'title', 'type' => 'blank' }
   end
 
   test 'should clear review comment' do
diff --git a/test/controllers/users_controller_test.rb b/test/controllers/users_controller_test.rb
index 4cae79f3..1e14c62c 100644
--- a/test/controllers/users_controller_test.rb
+++ b/test/controllers/users_controller_test.rb
@@ -51,7 +51,7 @@ class UsersControllerTest < ActionDispatch::IntegrationTest
     end
 
     assert_response :unprocessable_content
-    assert_includes response.parsed_body['errors'], { 'model' => 'user', 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'user', 'attribute' => 'name', 'type' => 'blank' }
   end
 
   test 'should create user for admin' do
@@ -102,7 +102,7 @@ class UsersControllerTest < ActionDispatch::IntegrationTest
 
     assert_response :unprocessable_content
     assert_not_equal '', @user.reload.name
-    assert_includes response.parsed_body['errors'], { 'model' => 'user', 'attribute' => 'name', 'type' => 'required' }
+    assert_includes response.parsed_body['errors'], { 'model' => 'user', 'attribute' => 'name', 'type' => 'blank' }
   end
 
   test 'should not update own permission if not admin' do

From beeede33ae61b8e982336834a0463e81c65c4220 Mon Sep 17 00:00:00 2001
From: Robbe Van Petegem <git@robbevp.be>
Date: Sat, 25 Jul 2026 13:40:30 +0200
Subject: [PATCH 5/7] Convert existing validations to specify type instead of
 message

---
 app/models/album.rb               | 11 ----------
 app/models/album_artist.rb        | 12 +++++++++++
 app/models/artist.rb              |  4 ++--
 app/models/location.rb            |  4 ++--
 app/models/playlist.rb            |  2 +-
 app/models/playlist_item.rb       |  2 +-
 test/models/album_artist_test.rb  | 36 +++++++++++++++++++++++++++++++
 test/models/album_test.rb         | 26 ----------------------
 test/models/artist_test.rb        |  4 ++--
 test/models/location_test.rb      |  4 ++--
 test/models/playlist_item_test.rb |  2 +-
 test/test_helper.rb               | 16 ++++++++++++++
 12 files changed, 75 insertions(+), 48 deletions(-)

diff --git a/app/models/album.rb b/app/models/album.rb
index 6b48bf80..6a609437 100644
--- a/app/models/album.rb
+++ b/app/models/album.rb
@@ -40,7 +40,6 @@ class Album < ApplicationRecord
   before_validation :normalize_artist_order
 
   validates :title, presence: true
-  validate :album_artist_separators
 
   normalized_col_generator :title
   nilify_blank_values :edition_description, :review_comment
@@ -81,14 +80,4 @@ def normalize_artist_order
       aa.save unless aa.new_record?
     end
   end
-
-  def album_artist_separators
-    album_artists.each do |aa|
-      if aa.order == album_artists.to_a.count
-        errors.add(:album_artists, 'aa-last-no-separator') unless aa.separator.nil?
-      elsif aa.separator.nil?
-        errors.add(:album_artists, 'aa-separator')
-      end
-    end
-  end
 end
diff --git a/app/models/album_artist.rb b/app/models/album_artist.rb
index 52926fb0..388a8dca 100644
--- a/app/models/album_artist.rb
+++ b/app/models/album_artist.rb
@@ -33,6 +33,18 @@ class AlbumArtist < ApplicationRecord
 
   validates :name, presence: true
   validates :order, presence: true
+  validate :separator_not_nil, unless: :last_item?
+  validates :separator, absence: { allow_blank: false }, if: :last_item?
 
   normalized_col_generator :name
+
+  private
+
+  def last_item?
+    order == album.album_artists.size
+  end
+
+  def separator_not_nil
+    errors.add(:separator, :blank) if separator.nil?
+  end
 end
diff --git a/app/models/artist.rb b/app/models/artist.rb
index b490b458..65b02429 100644
--- a/app/models/artist.rb
+++ b/app/models/artist.rb
@@ -42,8 +42,8 @@ class Artist < ApplicationRecord
 
   def merge(other)
     # we check if the artist to be merged have some overlap. If they do, we tell the user that they should resolve this first.
-    errors.add(:album_artists, 'aa.albums-overlap') if other.albums.map(&:id).intersect?(albums.map(&:id))
-    errors.add(:track_artists, 'ta.tracks-overlap') if other.track_artists.map { |ta| [ta.track_id, ta.role] }.intersect?(track_artists.map { |ta| [ta.track_id, ta.role] })
+    errors.add(:album_artists, :albums_overlap) if other.albums.map(&:id).intersect?(albums.map(&:id))
+    errors.add(:track_artists, :tracks_overlap) if other.track_artists.map { |ta| [ta.track_id, ta.role] }.intersect?(track_artists.map { |ta| [ta.track_id, ta.role] })
     return false if errors.present?
 
     other.album_artists.find_each do |aa|
diff --git a/app/models/location.rb b/app/models/location.rb
index a3fbce56..743e94f2 100644
--- a/app/models/location.rb
+++ b/app/models/location.rb
@@ -29,8 +29,8 @@ def expanded_path
 
   def cant_be_parent_or_subdir_of_other_location
     Location.find_each do |l|
-      errors.add(:path, 'path-is-subdirectoy') if expanded_path.fnmatch?(File.join(l.expanded_path, '**'))
-      errors.add(:path, 'path-is-parent') if l.expanded_path.fnmatch?(File.join(expanded_path, '**'))
+      errors.add(:path, :is_subdirectory) if expanded_path.fnmatch?(File.join(l.expanded_path, '**'))
+      errors.add(:path, :is_parent) if l.expanded_path.fnmatch?(File.join(expanded_path, '**'))
     end
   end
 
diff --git a/app/models/playlist.rb b/app/models/playlist.rb
index 28558888..975ea593 100644
--- a/app/models/playlist.rb
+++ b/app/models/playlist.rb
@@ -71,6 +71,6 @@ def item_ids_should_be_unique
     # When validating, we use `collect(&:item_id)` so we get the correct data
     # Regardless of whether the items were already saved
     doubles = items.collect(&:item_id).uniq!
-    errors.add(:items, 'item-ids-contains-double') unless doubles.nil?
+    errors.add(:items, :taken) unless doubles.nil?
   end
 end
diff --git a/app/models/playlist_item.rb b/app/models/playlist_item.rb
index 27b6f9f7..62789955 100644
--- a/app/models/playlist_item.rb
+++ b/app/models/playlist_item.rb
@@ -32,7 +32,7 @@ class PlaylistItem < ApplicationRecord
   private
 
   def item_type_should_match_playlist_type
-    errors.add(:item, 'item-type-different-from-playlist-type') unless item_type.downcase == playlist.playlist_type
+    errors.add(:item, :type_mismatch) unless item_type.downcase == playlist.playlist_type
   end
 
   def set_order
diff --git a/test/models/album_artist_test.rb b/test/models/album_artist_test.rb
index 2376e3dc..f00664cb 100644
--- a/test/models/album_artist_test.rb
+++ b/test/models/album_artist_test.rb
@@ -35,4 +35,40 @@ class AlbumArtistTest < ActiveSupport::TestCase
     assert_not album_artist.normalized_name.nil?
     assert_equal 'iouaaa', album_artist.normalized_name
   end
+
+  test 'should be valid if all except last have separator' do
+    album = build(:album, album_artists: [build(:album_artist, separator: ' / ', order: 1), build(:album_artist, separator: nil, order: 2)])
+    album_artist1 = album.album_artists.first
+    album_artist2 = album.album_artists.second
+
+    assert_predicate album_artist1, :valid?
+    assert_predicate album_artist2, :valid?
+  end
+
+  test 'should reject if album artists except last has no separator' do
+    album = build(:album, album_artists: [build(:album_artist, separator: nil, order: 1), build(:album_artist, separator: nil, order: 2)])
+    album_artist1 = album.album_artists.first
+    album_artist2 = album.album_artists.second
+
+    assert_not_predicate album_artist1, :valid?
+    assert_predicate album_artist2, :valid?
+    assert_error_of_kind album_artist1, :separator, :blank
+  end
+
+  test 'should allow album artists with empty string as separator' do
+    album = build(:album, album_artists: [build(:album_artist, separator: '', order: 1), build(:album_artist, separator: nil, order: 2)])
+    album_artist1 = album.album_artists.first
+    album_artist2 = album.album_artists.second
+
+    assert_predicate album_artist1, :valid?
+    assert_predicate album_artist2, :valid?
+  end
+
+  test 'should reject if last album artists has separator' do
+    album = build(:album, album_artists: [build(:album_artist, separator: ' / ')])
+    album_artist1 = album.album_artists.first
+
+    assert_not_predicate album_artist1, :valid?
+    assert_error_of_kind album_artist1, :separator, :present
+  end
 end
diff --git a/test/models/album_test.rb b/test/models/album_test.rb
index 69208871..730a323e 100644
--- a/test/models/album_test.rb
+++ b/test/models/album_test.rb
@@ -35,32 +35,6 @@ class AlbumTest < ActiveSupport::TestCase
     assert_equal 'iouaaa', album.normalized_title
   end
 
-  test 'should pass if all but last album artists have separator' do
-    album = build(:album, album_artists: [build(:album_artist, separator: ' / ', order: 1), build(:album_artist, separator: nil, order: 2)])
-
-    assert_predicate album, :valid?
-  end
-
-  test 'should reject if album artists except last has no separator' do
-    album = build(:album, album_artists: [build(:album_artist, separator: nil, order: 1), build(:album_artist, separator: nil, order: 2)])
-
-    assert_not album.valid?
-    assert_not_empty album.errors[:album_artists]
-  end
-
-  test 'should allow album artists with empty string as separator' do
-    album = build(:album, album_artists: [build(:album_artist, separator: '', order: 1), build(:album_artist, separator: nil, order: 2)])
-
-    assert_predicate album, :valid?
-  end
-
-  test 'should reject if last album artists has separator' do
-    album = build(:album, album_artists: [build(:album_artist, separator: ' / ')])
-
-    assert_not album.valid?
-    assert_not_empty album.errors[:album_artists]
-  end
-
   test 'should normalize order of album artists' do
     aa1 = build(:album_artist, order: 5)
     aa2 = build(:album_artist, order: 2)
diff --git a/test/models/artist_test.rb b/test/models/artist_test.rb
index ebab5bdc..6e4f5572 100644
--- a/test/models/artist_test.rb
+++ b/test/models/artist_test.rb
@@ -70,7 +70,7 @@ class ArtistTest < ActiveSupport::TestCase
       artist2.merge(artist1)
     end
 
-    assert_not_empty artist2.errors[:track_artists]
+    assert_error_of_kind artist2, :track_artists, :tracks_overlap
   end
 
   test 'should be able to merge artists if they share track_artist with different role' do
@@ -142,7 +142,7 @@ class ArtistTest < ActiveSupport::TestCase
       artist2.merge(artist1)
     end
 
-    assert_not_empty artist2.errors[:album_artists]
+    assert_error_of_kind artist2, :album_artists, :albums_overlap
   end
 
   test 'should keep not override image during merge' do
diff --git a/test/models/location_test.rb b/test/models/location_test.rb
index 75d36cdd..a815a113 100644
--- a/test/models/location_test.rb
+++ b/test/models/location_test.rb
@@ -23,14 +23,14 @@ class LocationTest < ActiveSupport::TestCase
     child = build(:location, path: '/var/parent/music')
 
     assert_not child.valid?
-    assert_not_empty child.errors[:path]
+    assert_error_of_kind child, :path, :is_subdirectory
   end
 
   test 'location cant be parent of other location' do
     parent = build(:location, path: '/var')
 
     assert_not parent.valid?
-    assert_not_empty parent.errors[:path]
+    assert_error_of_kind parent, :path, :is_parent
   end
 
   test 'should be able to add similar siblings' do
diff --git a/test/models/playlist_item_test.rb b/test/models/playlist_item_test.rb
index 26d1d817..0a8fa164 100644
--- a/test/models/playlist_item_test.rb
+++ b/test/models/playlist_item_test.rb
@@ -35,7 +35,7 @@ class PlayListItemTest < ActiveSupport::TestCase
     item = build(:playlist_item, :for_track, playlist:)
 
     assert_not_predicate item, :valid?
-    assert_not_empty item.errors[:item]
+    assert_error_of_kind item, :item, :type_mismatch
   end
 
   test 'item should get order if not present' do
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 88a3173c..5279c4ee 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -33,10 +33,26 @@ def with_stubbed_audio_file_convert(implementation = nil)
   end
 end
 
+module ValidationAssertions
+  ##
+  # Assertion to check whether an object has an error with the specified attribute and type
+  # The object should implement `ActiveModel::Errors` for this to work
+  #
+  # For a list of the types for different validators, see [the rails guides](https://guides.rubyonrails.org/i18n.html#error-message-interpolation)
+  def assert_error_of_kind(object, attribute, type = :invalid)
+    attribute_errors = object.errors.filter { |e| e.attribute == attribute }
+    message = "Expected #{object.class.name} to have an error of type #{type} for #{attribute}, but no error was found."
+    message << "\nThe object does have the following errors for #{attribute}: #{attribute_errors}" if attribute_errors.present?
+
+    assert object.errors.of_kind?(attribute, type), message
+  end
+end
+
 class ActiveSupport::TestCase
   include FactoryBot::Syntax::Methods
   include ActiveJob::TestHelper
   include AudioFileTestHelper
+  include ValidationAssertions
 
   # Run tests in parallel with specified workers
   parallelize(workers: :number_of_processors)

From 082572ad3fd3d2b955dbea41da50dd58679cc33e Mon Sep 17 00:00:00 2001
From: Robbe Van Petegem <git@robbevp.be>
Date: Sat, 25 Jul 2026 13:40:45 +0200
Subject: [PATCH 6/7] Drop error type map

---
 app/controllers/application_controller.rb | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 53b2e841..92d69d8e 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -2,9 +2,6 @@ class ApplicationController < ActionController::API
   include Pundit::Authorization
   include ActionController::HttpAuthentication::Token::ControllerMethods
 
-  # This map only includes the type of validation errors that we could have inside the app
-  ERROR_TYPE_MAP = { blank: :blank, taken: :taken }.freeze
-
   etag { params[:page] }
   etag { params[:per_page] }
 
@@ -46,7 +43,7 @@ def stale?(scope:, **)
   end
 
   def transform_error_for_json(object, error)
-    { model: object.model_name.singular, attribute: error.attribute, type: ERROR_TYPE_MAP[error.type] }
+    { model: object.model_name.singular, attribute: error.attribute, type: error.type }
   end
 
   # This method expects an instance of a class that includes `ActiveModel::Errors`

From 83498a7d889c7d703aa8032242c3a497c574e888 Mon Sep 17 00:00:00 2001
From: Robbe Van Petegem <git@robbevp.be>
Date: Sat, 25 Jul 2026 13:49:53 +0200
Subject: [PATCH 7/7] Fix merge

---
 app/models/artist.rb | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/app/models/artist.rb b/app/models/artist.rb
index 65b02429..9eb3aba7 100644
--- a/app/models/artist.rb
+++ b/app/models/artist.rb
@@ -47,7 +47,9 @@ def merge(other)
     return false if errors.present?
 
     other.album_artists.find_each do |aa|
-      aa.update(artist_id: id)
+      # rubocop:disable Rails/SkipsModelValidations -- we skip validations, as this would check the separators while we're moving over the album artists
+      aa.update_columns(artist_id: id)
+      # rubocop:enable Rails/SkipsModelValidations
     end
 
     other.track_artists.find_each do |ta|