Fix an issue in the where.associated method

Author: saleh-alhaddad

activerecord/CHANGELOG.md

@@ -3,6 +3,22 @@
 
     *Jason Nochlin*
 
+*   The fix ensures that the association is joined using the appropriate join type
+    (either inner join or left outer join) based on the existing joins in the scope.
+
+    This prevents unintentional overrides of existing join types and ensures consistency in the generated SQL queries.
+
+    Example:
+
+
+
+    ```ruby
+    # `associated` will use `LEFT JOIN` instead of using `JOIN`
+    Post.left_joins(:author).where.associated(:author)
+    ```
+
+    *Saleh Alhaddad*
+
 *   Fix an issue where `ActiveRecord::Encryption` configurations are not ready before the loading
     of Active Record models, when an application is eager loaded. As a result, encrypted attributes
     could be misconfigured in some cases.

activerecord/lib/active_record/relation/query_methods.rb

@@ -72,10 +72,26 @@ def not(opts, *rest)
       #    # INNER JOIN "authors" ON "authors"."id" = "posts"."author_id"
       #    # INNER JOIN "comments" ON "comments"."post_id" = "posts"."id"
       #    # WHERE "authors"."id" IS NOT NULL AND "comments"."id" IS NOT NULL
+      #
+      # You can define join type in the scope and +associated+ will not use `JOIN` by default.
+      #
+      #    Post.left_joins(:author).where.associated(:author)
+      #    # SELECT "posts".* FROM "posts"
+      #    # LEFT OUTER JOIN "authors" "authors"."id" = "posts"."author_id"
+      #    # WHERE "authors"."id" IS NOT NULL
+      #
+      #    Post.left_joins(:comments).where.associated(:author)
+      #    # SELECT "posts".* FROM "posts"
+      #    # INNER JOIN "authors" ON "authors"."id" = "posts"."author_id"
+      #    # LEFT OUTER JOIN "comments" ON "comments"."post_id" = "posts"."id"
+      #   #  WHERE "author"."id" IS NOT NULL
       def associated(*associations)
         associations.each do |association|
           reflection = scope_association_reflection(association)
-          @scope.joins!(association)
+          unless @scope.joins_values.include?(reflection.name) || @scope.left_outer_joins_values.include?(reflection.name)
+            @scope.joins!(association)
+          end
+
           if reflection.options[:class_name]
             self.not(association => { reflection.association_primary_key => nil })
           else

activerecord/test/cases/relation/where_chain_test.rb

@@ -92,6 +92,27 @@ def test_associated_with_enum_extended_late
       assert_equal Author.find(2), Author.order(id: :desc).joins(:reading_listing).where.associated(:reading_listing).extending(Author::NamedExtension).first
     end
 
+    def test_associated_with_add_joins_before
+      Comment.joins(:children).where.associated(:children).tap do |relation|
+        assert_includes     relation, comments(:greetings)
+        assert_not_includes relation, comments(:more_greetings)
+      end
+    end
+
+    def test_associated_with_add_left_joins_before
+      Comment.left_joins(:children).where.associated(:children).tap do |relation|
+        assert_includes     relation, comments(:greetings)
+        assert_not_includes relation, comments(:more_greetings)
+      end
+    end
+
+    def test_associated_with_add_left_outer_joins_before
+      Comment.left_outer_joins(:children).where.associated(:children).tap do |relation|
+        assert_includes     relation, comments(:greetings)
+        assert_not_includes relation, comments(:more_greetings)
+      end
+    end
+
     def test_missing_with_association
       assert_predicate posts(:authorless).author, :blank?
       assert_equal [posts(:authorless)], Post.where.missing(:author).to_a