Add filename to error messages for ActiveStorage validation (#39)

Author: Copilot

.gitignore

@@ -1,4 +1,5 @@
 /.bundle/
+/vendor/bundle/
 /.yardoc
 /_yardoc/
 /coverage/

lib/activestorage/validator/blob.rb

@@ -7,14 +7,14 @@ def validate_each(record, attribute, values) # rubocop:disable Metrics/AbcSize
         Array(values).each do |value|
           if options[:size_range].present?
             if options[:size_range].min > value.blob.byte_size
-              record.errors.add(attribute, :min_size_error, min_size: ActiveSupport::NumberHelper.number_to_human_size(options[:size_range].min))
+              record.errors.add(attribute, :min_size_error, min_size: ActiveSupport::NumberHelper.number_to_human_size(options[:size_range].min), filename: value.blob.filename.to_s)
             elsif options[:size_range].max < value.blob.byte_size
-              record.errors.add(attribute, :max_size_error, max_size: ActiveSupport::NumberHelper.number_to_human_size(options[:size_range].max))
+              record.errors.add(attribute, :max_size_error, max_size: ActiveSupport::NumberHelper.number_to_human_size(options[:size_range].max), filename: value.blob.filename.to_s)
             end
           end
 
           unless valid_content_type?(value.blob)
-            record.errors.add(attribute, :content_type)
+            record.errors.add(attribute, :content_type, filename: value.blob.filename.to_s)
           end
         end
       end

spec/activestorage/validator/blob_spec.rb

@@ -106,4 +106,27 @@
       it { expect(User.new(files: [create_file_blob(filename: 'dummy.txt', content_type: 'text/plain')]).valid?).to eq false }
     end
   end
+
+  describe 'filename parameter in validation errors' do
+    context 'content_type validation' do
+      before do
+        User.validates :file, blob: { content_type: /^image/ }
+        User.validates :files, blob: { content_type: /^image/ }
+      end
+
+      it "passes filename for has_one_attached" do
+        user = User.new(file: create_file_blob(filename: 'dummy.txt', content_type: 'text/plain'))
+        user.validate
+        error_detail = user.errors.details[:file][0]
+        expect(error_detail[:filename]).to eq('dummy.txt')
+      end
+
+      it "passes filename for has_many_attached" do
+        user = User.new(files: [create_file_blob(filename: 'dummy.txt', content_type: 'text/plain')])
+        user.validate
+        error_detail = user.errors.details[:files][0]
+        expect(error_detail[:filename]).to eq('dummy.txt')
+      end
+    end
+  end
 end