Remove invalid upload files

decidim-core/app/commands/decidim/validate_upload.rb

@@ -7,9 +7,19 @@ def initialize(form)
     end
 
     def call
-      return broadcast(:invalid, @form.errors) if @form.invalid?
+      if @form.invalid?
+        remove_invalid_file
+        return broadcast(:invalid, @form.errors)
+      end
 
       broadcast(:ok)
     end
+
+    private
+
+    def remove_invalid_file
+      blob = ActiveStorage::Blob.find_signed(@form.blob)
+      blob.purge if blob.present?
+    end
   end
 end

decidim-core/spec/commands/decidim/validate_upload_spec.rb

@@ -9,25 +9,38 @@ module Decidim
       let(:form) do
         double(
           invalid?: invalid,
+          blob:,
           errors:
         )
       end
       let(:invalid) { false }
       let(:errors) { [] }
+      let(:blob) { "foobar" }
 
       describe "when form is valid" do
         it "broadcasts ok" do
           expect { command.call }.to broadcast(:ok)
         end
+
+        it "ignores file removal" do
+          expect(ActiveStorage::Blob).not_to receive(:find_signed).with(blob)
+          command.call
+        end
       end
 
       describe "when the form is not valid" do
         let(:invalid) { true }
         let(:errors) { ["File too dummy"] }
 
         it "broadcasts invalid" do
+          allow(ActiveStorage::Blob).to receive(:find_signed).with(blob).and_return(double(purge: true))
           expect { command.call }.to broadcast(:invalid, errors)
         end
+
+        it "removes the invalid file" do
+          expect(ActiveStorage::Blob).to receive(:find_signed)
+          command.call
+        end
       end
     end
   end