Merge branch 'attachment-processing-block-parsing' into develop

app/models/incoming_message.rb

@@ -41,6 +41,8 @@ class IncomingMessage < ApplicationRecord
   include CacheAttributesFromRawEmail
   include Taggable
 
+  UnableToExtractAttachments = Class.new(StandardError)
+
   MAX_ATTACHMENT_TEXT_CLIPPED = 1_000_000 # 1Mb ish
 
   belongs_to :info_request,
@@ -470,8 +472,18 @@ def extract_attachments
       attachments += _uudecode_attachments(main_part.body, c)
     end
 
-    # Purge old attachments that have been rebuilt with a new hexdigest
-    (foi_attachments - attachments).each(&:mark_for_destruction)
+    # Purge old public attachments that will be rebuilt with a new hexdigest
+    old_attachments = (foi_attachments - attachments)
+    hidden_old_attachments = old_attachments.reject { _1.is_public? }
+
+    if hidden_old_attachments.any?
+      # if there are hidden attachments error as we don't want to re-build and
+      # lose the prominence as this will make them public
+      raise UnableToExtractAttachments, "due to prominence of attachments " \
+        "(ID=#{hidden_old_attachments.map(&:id).join(', ')})"
+    else
+      old_attachments.each(&:mark_for_destruction)
+    end
   end
 
   # Returns body text as HTML with quotes flattened, and emails removed.

spec/models/incoming_message_spec.rb

@@ -1087,6 +1087,23 @@ def populate_raw_email(fixture)
     expect(im._get_attachment_text_internal.valid_encoding?).to be true
   end
 
+  it 'does not raise error if existing hidden attachment will be retained' do
+    incoming_message = FactoryBot.create(:incoming_message)
+    foi_attachment = incoming_message.foi_attachments.first
+    foi_attachment.update(prominence: 'hidden')
+
+    expect { incoming_message.extract_attachments! }.to_not raise_error
+  end
+
+  it 'raises error if existing hidden attachment will be deleted' do
+    incoming_message = FactoryBot.create(:incoming_message)
+    foi_attachment = incoming_message.foi_attachments.first
+    foi_attachment.update(prominence: 'hidden', hexdigest: '123')
+
+    expect { incoming_message.extract_attachments! }.to raise_error(
+      IncomingMessage::UnableToExtractAttachments
+    )
+  end
 end
 
 RSpec.describe IncomingMessage, 'when getting the body of a message for html display' do