Fix join middle table alias when using HABTM

In using HABTM, join middle table alias is combined with the associated
models name without sort, while middle table name is combined with those
models name with sort.

Fixes #36742.

2 files changed, 10 insertions, 3 deletions

diff --git a/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb b/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
index 6ad4c75fb5..2072f93194 100644
--- a/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
+++ b/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
@@ -62,7 +62,7 @@ module ActiveRecord::Associations::Builder # :nodoc:
 
     def middle_reflection(join_model)
       middle_name = [lhs_model.name.downcase.pluralize,
-                     association_name].join("_").gsub("::", "_").to_sym
+                     association_name.to_s].sort.join("_").gsub("::", "_").to_sym
       middle_options = middle_options join_model
 
       HasMany.create_reflection(lhs_model,
diff --git a/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb b/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
index 25cfa0a723..de9742b250 100644
--- a/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
@@ -700,10 +700,17 @@ class HasAndBelongsToManyAssociationsTest < ActiveRecord::TestCase
     assert_equal ["id"], developers(:david).projects.select(:id).first.attributes.keys
   end
 
+  def test_join_middle_table_alias
+    assert_equal(
+      2,
+      Project.includes(:developers_projects).where.not("developers_projects.joined_on": nil).to_a.size
+    )
+  end
+
   def test_join_table_alias
     assert_equal(
       3,
-      Developer.includes(projects: :developers).where.not("projects_developers_projects_join.joined_on": nil).to_a.size
+      Developer.includes(projects: :developers).where.not("developers_projects_projects_join.joined_on": nil).to_a.size
     )
   end
 
@@ -716,7 +723,7 @@ class HasAndBelongsToManyAssociationsTest < ActiveRecord::TestCase
 
     assert_equal(
       3,
-      Developer.includes(projects: :developers).where.not("projects_developers_projects_join.joined_on": nil).group(group.join(",")).to_a.size
+      Developer.includes(projects: :developers).where.not("developers_projects_projects_join.joined_on": nil).group(group.join(",")).to_a.size
     )
   end