Decouple building `AliasTracker` from `JoinDependency`

This is preparation to respect parent relation's alias tracking for
fixing #30681.

7 files changed, 16 insertions, 17 deletions

diff --git a/activerecord/lib/active_record/associations/alias_tracker.rb b/activerecord/lib/active_record/associations/alias_tracker.rb
index 096f016976..358cdabc7f 100644
--- a/activerecord/lib/active_record/associations/alias_tracker.rb
+++ b/activerecord/lib/active_record/associations/alias_tracker.rb
@@ -6,22 +6,16 @@ module ActiveRecord
   module Associations
     # Keeps track of table aliases for ActiveRecord::Associations::JoinDependency
     class AliasTracker # :nodoc:
-      def self.create(connection, initial_table)
-        aliases = Hash.new(0)
-        aliases[initial_table] = 1
-        new(connection, aliases)
-      end
-
-      def self.create_with_joins(connection, initial_table, joins)
+      def self.create(connection, initial_table, joins)
         if joins.empty?
-          create(connection, initial_table)
+          aliases = Hash.new(0)
         else
           aliases = Hash.new { |h, k|
             h[k] = initial_count_for(connection, k, joins)
           }
-          aliases[initial_table] = 1
-          new(connection, aliases)
         end
+        aliases[initial_table] = 1
+        new(connection, aliases)
       end
 
       def self.initial_count_for(connection, name, table_joins)
diff --git a/activerecord/lib/active_record/associations/association_scope.rb b/activerecord/lib/active_record/associations/association_scope.rb
index 6118cef913..11967e0571 100644
--- a/activerecord/lib/active_record/associations/association_scope.rb
+++ b/activerecord/lib/active_record/associations/association_scope.rb
@@ -23,8 +23,7 @@ module ActiveRecord
         reflection = association.reflection
         scope = klass.unscoped
         owner = association.owner
-        alias_tracker = AliasTracker.create(klass.connection, scope.table.name)
-        chain = get_chain(reflection, association, alias_tracker)
+        chain = get_chain(reflection, association, scope.alias_tracker)
 
         scope.extending! reflection.extensions
         add_constraints(scope, owner, chain)
diff --git a/activerecord/lib/active_record/associations/join_dependency.rb b/activerecord/lib/active_record/associations/join_dependency.rb
index 23741b2f6a..b70b680885 100644
--- a/activerecord/lib/active_record/associations/join_dependency.rb
+++ b/activerecord/lib/active_record/associations/join_dependency.rb
@@ -90,8 +90,8 @@ module ActiveRecord
       #    associations # => [:appointments]
       #    joins # =>  []
       #
-      def initialize(base, table, associations, joins, eager_loading: true)
-        @alias_tracker = AliasTracker.create_with_joins(base.connection, table.name, joins)
+      def initialize(base, table, associations, alias_tracker, eager_loading: true)
+        @alias_tracker = alias_tracker
         @eager_loading = eager_loading
         tree = self.class.make_tree associations
         @join_root = JoinBase.new(base, table, build(tree, base))
diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb
index 3517091a6e..1f59a0c53a 100644
--- a/activerecord/lib/active_record/relation.rb
+++ b/activerecord/lib/active_record/relation.rb
@@ -551,6 +551,10 @@ module ActiveRecord
       limit_value || offset_value
     end
 
+    def alias_tracker(joins = []) # :nodoc:
+      ActiveRecord::Associations::AliasTracker.create(connection, table.name, joins)
+    end
+
     protected
 
       def load_records(records)
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index c92d5a52f4..5d4b549470 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -390,7 +390,9 @@ module ActiveRecord
 
       def construct_join_dependency(joins = [], eager_loading: true)
         including = eager_load_values + includes_values
-        ActiveRecord::Associations::JoinDependency.new(klass, table, including, joins, eager_loading: eager_loading)
+        ActiveRecord::Associations::JoinDependency.new(
+          klass, table, including, alias_tracker(joins), eager_loading: eager_loading
+        )
       end
 
       def construct_relation_for_association_calculations
diff --git a/activerecord/lib/active_record/relation/merger.rb b/activerecord/lib/active_record/relation/merger.rb
index 03824ffff9..ebc72d28fd 100644
--- a/activerecord/lib/active_record/relation/merger.rb
+++ b/activerecord/lib/active_record/relation/merger.rb
@@ -122,7 +122,7 @@ module ActiveRecord
             end
 
             join_dependency = ActiveRecord::Associations::JoinDependency.new(
-              other.klass, other.table, joins_dependency, []
+              other.klass, other.table, joins_dependency, other.alias_tracker
             )
 
             relation.joins! rest
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index e76ad05b71..fb5beeffef 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -1013,7 +1013,7 @@ module ActiveRecord
         join_list = join_nodes + convert_join_strings_to_ast(manager, string_joins)
 
         join_dependency = ActiveRecord::Associations::JoinDependency.new(
-          klass, table, association_joins, join_list
+          klass, table, association_joins, alias_tracker(join_list)
         )
 
         joins = join_dependency.join_constraints(stashed_association_joins, join_type)