Allow HABTM to use non-standard table names

lib/jsonapi_compliable/adapters/active_record_sideloading.rb

@@ -94,10 +94,14 @@ def has_and_belongs_to_many(association_name, scope: nil, resource:, foreign_key
             parent_ids = parents.map { |p| p.send(primary_key) }
             parent_ids.uniq!
             parent_ids.compact!
+
+            table_name = parents[0]
+              .class.reflections[through.to_s].klass.table_name
+
             _scope.call
               .joins(through)
               .preload(through) # otherwise n+1 as we reference in #assign
-              .where(through => { fk => parent_ids })
+              .where(table_name => { fk => parent_ids })
               .distinct
           end
 

spec/fixtures/legacy.rb

@@ -20,6 +20,12 @@
     t.integer :hobby_id
   end
 
+  # test non-standard table name
+  create_table :author_hobby do |t|
+    t.integer :author_id
+    t.integer :hobby_id
+  end
+
   create_table :hobbies do |t|
     t.string :name
   end

spec/integration/rails/finders_spec.rb

@@ -367,6 +367,21 @@ def json
         expect(author1_hobbies.size).to eq(2)
         expect(author2_hobbies.size).to eq(1)
       end
+
+      context 'when the table name does not match the association name' do
+        before do
+          AuthorHobby.table_name = :author_hobby
+        end
+
+        let!(:other_table_hobby1)  { Hobby.create!(name: 'Fishing', authors: [author1]) }
+        let!(:other_table_hobby2)  { Hobby.create!(name: 'Woodworking', authors: [author1, author2]) }
+
+        it 'still works' do
+          get :index, params: { include: 'hobbies' }
+          expect(ids_for('hobbies'))
+            .to eq([other_table_hobby1.id, other_table_hobby2.id])
+        end
+      end
     end
 
     context 'sideloading self-referential' do