1 files changed, 43 insertions, 0 deletions
diff --git a/app/models/legacy_diff_discussion.rb b/app/models/legacy_diff_discussion.rb
new file mode 100644
index 00000000000..3c1d34db5fa
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+++ b/app/models/legacy_diff_discussion.rb
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+# A discussion on merge request or commit diffs consisting of `LegacyDiffNote` notes.
+#
+# All new diff discussions are of the type `DiffDiscussion`, but any diff discussions created
+# before the introduction of the new implementation still use `LegacyDiffDiscussion`.
+#
+# A discussion of this type is never resolvable.
+class LegacyDiffDiscussion < Discussion
+  include DiscussionOnDiff
+
+  memoized_values << :active
+
+  def self.note_class
+    LegacyDiffNote
+  end
+
+  def legacy_diff_discussion?
+    true
+  end
+
+  def active?(*args)
+    return @active if @active.present?
+
+    @active = first_note.active?(*args)
+  end
+
+  def collapsed?
+    !active?
+  end
+
+  def merge_request_version_params
+    return unless for_merge_request?
+
+    if active?
+      {}
+    else
+      nil
+    end
+  end
+
+  def reply_attributes
+    super.merge(line_code: line_code)
+  end
+end