Handle commas in weight system notes in code, not the DB

We will tackle the migration in a future release, as a background migration.

For now, hide these commas at the model layer.

ee/app/models/ee/note.rb

@@ -11,6 +11,24 @@ module EE
       noteable.is_a?(Epic)
     end
 
+    # Remove with https://gitlab.com/gitlab-org/gitlab-ee/issues/6347
+    def note
+      raw_note = super
+
+      return raw_note unless system? && system_note_metadata&.action == 'weight'
+
+      raw_note.delete(',')
+    end
+
+    # Remove with https://gitlab.com/gitlab-org/gitlab-ee/issues/6347
+    def note_html
+      raw_note_html = super
+
+      return raw_note_html unless system? && system_note_metadata&.action == 'weight'
+
+      raw_note_html.delete(',')
+    end
+
     override :for_project_noteable?
     def for_project_noteable?
       !for_epic? && super

ee/db/migrate/20180530201303_remove_commas_from_weight_note.rb

-class RemoveCommasFromWeightNote < ActiveRecord::Migration
-  include Gitlab::Database::MigrationHelpers
-
-  DOWNTIME = false
-
-  disable_ddl_transaction!
-
-  def up
-    add_concurrent_index(:system_note_metadata, :action, where: "action = 'weight'")
-
-    notes_table = Arel::Table.new(:notes)
-    metadata_table = Arel::Table.new(:system_note_metadata)
-    update_value = Arel.sql("TRIM(TRAILING ',' FROM note), note_html = NULL")
-
-    weight_system_notes =
-      notes_table
-        .join(metadata_table).on(notes_table[:id].eq(metadata_table[:note_id]))
-        .where(metadata_table[:action].eq('weight'))
-        .where(notes_table[:system].eq(true))
-        .where(notes_table[:note].matches('%,'))
-        .project(notes_table[:id])
-
-    if Gitlab::Database.mysql?
-      weight_system_notes = weight_system_notes.from(
-        notes_table.project([notes_table[:id], notes_table[:system]]).as('notes')
-      )
-    end
-
-    update_column_in_batches(:notes, :note, update_value) do |table, query|
-      query.where(table[:id].in(weight_system_notes))
-    end
-
-    remove_concurrent_index(:system_note_metadata, :action)
-  end
-
-  def down
-    # We can't reliably find notes that would need a comma, so do nothing
-  end
-end

ee/spec/migrations/remove_commas_from_weight_note_spec.rb

-require 'spec_helper'
-require Rails.root.join('ee', 'db', 'migrate', '../../db/migrate/20180530201303_remove_commas_from_weight_note.rb')
-
-describe RemoveCommasFromWeightNote, :migration do
-  RSpec::Matchers.define_negated_matcher :not_change, :change
-
-  describe '#up' do
-    let(:notes) { table(:notes) }
-    let(:system_note_metadata) { table(:system_note_metadata) }
-
-    def create_system_note(note, metadata_action)
-      notes.create(note: note, system: true).tap do |system_note|
-        system_note_metadata.create(note_id: system_note.id, action: metadata_action)
-      end
-    end
-
-    let(:weight_note_with_comma) { create_system_note('changed weight to 5,', 'weight') }
-    let(:weight_note_without_comma) { create_system_note('removed the weight', 'weight') }
-    let(:title_note) { create_system_note('changed title from 5, to 5,', 'title') }
-    let(:user_note) { notes.create(note: 'changed weight to 5,') }
-
-    it 'removes all trailing commas from weight system notes' do
-      expect { migrate! }
-        .to change { Note.where("note LIKE '%,'").count }.from(3).to(2)
-        .and change { weight_note_with_comma.reload.note }
-        .and not_change { weight_note_without_comma.reload.note }
-        .and not_change { title_note.reload.note }
-        .and not_change { user_note.reload.note }
-    end
-  end
-end

ee/spec/models/ee/note_spec.rb

+require 'spec_helper'
+
+describe EE::Note do
+  # Remove with https://gitlab.com/gitlab-org/gitlab-ee/issues/6347
+  describe "#note and #note_html overrides for weight" do
+    using RSpec::Parameterized::TableSyntax
+
+    where(:system, :action, :result) do
+      false | nil      | 'this, has, some, commas'
+      true  | nil      | 'this, has, some, commas'
+      true  | 'relate' | 'this, has, some, commas'
+      true  | 'weight' | 'this has some commas'
+    end
+
+    with_them do
+      let(:note) { create(:note, system: system, note: 'this, has, some, commas') }
+
+      before do
+        create(:system_note_metadata, action: action, note: note) if action
+      end
+
+      it 'returns the right raw note' do
+        expect(note.note).to eq(result)
+      end
+
+      it 'returns the right HTML' do
+        expect(note.note_html).to eq("<p dir=\"auto\">#{result}</p>")
+      end
+    end
+  end
+end