Merge branch '8181-fix-blob-integrity-error' into develop

app/models/foi_attachment.rb

@@ -96,6 +96,8 @@ def body=(d)
     ensure_filename!
     if file.attached?
       file_blob.upload(StringIO.new(d.to_s), identify: false)
+      file_blob.save
+
     else
       file.attach(
         io: StringIO.new(d.to_s),

config/sidekiq.yml-example

@@ -7,6 +7,8 @@ production:
 :queues:
   - default
   - xapian
+  - low
 
 :limits:
   xapian: 1
+  low: 1

lib/tasks/storage/storage.rb

@@ -46,7 +46,17 @@ def mirror
     count = mirrorable_blobs.count
 
     mirrorable_blobs.find_each.with_index do |blob, index|
-      mirror_service.mirror(blob.key, checksum: blob.checksum)
+      begin
+        mirror_service.mirror(blob.key, checksum: blob.checksum)
+      rescue ActiveStorage::IntegrityError => ex
+        raise ex unless @klass == FoiAttachment
+
+        # Fix for https://github.com/mysociety/alaveteli/issues/8181
+        attachment = FoiAttachment.joins(:file_blob).
+          find_by(active_storage_blobs: { id: blob })
+        # Running the attachment masking will also mirror the file
+        FoiAttachmentMaskJob.set(queue: :low).perform_later(attachment)
+      end
 
       print "#{prefix}: Mirrored #{index + 1}/#{count}"
     end

spec/models/foi_attachment_spec.rb

@@ -125,6 +125,16 @@
       expect { attachment.update(body: 'masked', masked_at: Time.now) }.
         to_not change { attachment.file_blob.metadata }
     end
+
+    it 'persists changes to existing blob checksum' do
+      attachment = FactoryBot.create(
+        :foi_attachment, :unmasked, body: 'unmasked'
+      )
+
+      expect { attachment.update(body: 'masked', masked_at: Time.now) }.
+        to change { attachment.file_blob.checksum }
+      expect(attachment.file_blob.changed?).to eq false
+    end
   end
 
   describe '#body' do