Clear up dependency destruction chain

Buckets destroy their bubbles, which destroy their thread entries, which destroy their threadables, which is how comments end up destroyed, and then rollups end up deleting their events

app/models/bubble/commentable.rb

@@ -2,7 +2,7 @@ module Bubble::Commentable
   extend ActiveSupport::Concern
 
   included do
-    has_many :comments, dependent: :destroy
+    has_many :comments
 
     scope :ordered_by_comments, -> { left_joins(:comments).group(:id).order("COUNT(comments.id) DESC") }
   end

app/models/bubble/eventable.rb

@@ -2,7 +2,7 @@ module Bubble::Eventable
   extend ActiveSupport::Concern
 
   included do
-    has_many :events, dependent: :delete_all
+    has_many :events
 
     after_create -> { track_event :created }
   end

app/models/concerns/threadable.rb

@@ -2,7 +2,7 @@ module Threadable
   extend ActiveSupport::Concern
 
   included do
-    has_one :thread_entry, as: :threadable, dependent: :destroy
+    has_one :thread_entry, as: :threadable
 
     after_create { create_thread_entry! bubble: bubble }
     after_update { bubble.touch }

app/models/rollup.rb

@@ -3,5 +3,5 @@ class Rollup < ApplicationRecord
 
   belongs_to :bubble
 
-  has_many :events, -> { chronologically }
+  has_many :events, -> { chronologically }, dependent: :delete_all
 end

app/models/thread_entry.rb

@@ -1,7 +1,7 @@
 class ThreadEntry < ApplicationRecord
   belongs_to :bubble
 
-  delegated_type :threadable, types: %w[ Comment Rollup ]
+  delegated_type :threadable, types: %w[ Comment Rollup ], dependent: :destroy
 
   scope :chronologically, -> { order created_at: :asc, id: :desc }
 end

test/fixtures/thread_entries.yml

@@ -24,5 +24,17 @@ logo_5:
   created_at: <%= 1.hour.ago %>
 
 layout_1:
+  bubble: layout
+  threadable: layout_initial_activity (Rollup)
+
+layout_2:
   bubble: layout
   threadable: layout_overflowing_david (Comment)
+
+text_1:
+  bubble: text
+  threadable: text_initial_activity (Rollup)
+
+shipping_1:
+  bubble: shipping
+  threadable: shipping_initial_activity (Rollup)