Ensure to calculate column aliases after all table aliases are constructed

Currently, column aliases which is used for eager loading are calculated
before constructing all table aliases in FROM clause.

`JoinDependency#join_constraints` constructs table aliases for `joins`
first, and then always re-constructs table aliases for eager loading.

If both `joins` and eager loading are given a same table association,
the re-construction would cause the discrepancy between column aliases
and table aliases.

To avoid the discrepancy, the column aliases should be calculated after
all table aliases are constructed.

Fixes #30603.

1 files changed, 9 insertions, 7 deletions

diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index db9101a168..5b4ba85316 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -1018,19 +1018,19 @@ module ActiveRecord
       def build_join_query(manager, buckets, join_type, aliases)
         buckets.default = []
 
-        association_joins         = buckets[:association_join]
-        stashed_association_joins = buckets[:stashed_join]
-        join_nodes                = buckets[:join_node].uniq
-        string_joins              = buckets[:string_join].map(&:strip).uniq
+        association_joins = buckets[:association_join]
+        stashed_joins     = buckets[:stashed_join]
+        join_nodes        = buckets[:join_node].uniq
+        string_joins      = buckets[:string_join].map(&:strip).uniq
 
         join_list = join_nodes + convert_join_strings_to_ast(string_joins)
         alias_tracker = alias_tracker(join_list, aliases)
 
         join_dependency = ActiveRecord::Associations::JoinDependency.new(
-          klass, table, association_joins, alias_tracker
+          klass, table, association_joins
         )
 
-        joins = join_dependency.join_constraints(stashed_association_joins, join_type)
+        joins = join_dependency.join_constraints(stashed_joins, join_type, alias_tracker)
         joins.each { |join| manager.from(join) }
 
         manager.join_sources.concat(join_list)
@@ -1056,11 +1056,13 @@ module ActiveRecord
       end
 
       def arel_columns(columns)
-        columns.map do |field|
+        columns.flat_map do |field|
           if (Symbol === field || String === field) && (klass.has_attribute?(field) || klass.attribute_alias?(field)) && !from_clause.value
             arel_attribute(field)
           elsif Symbol === field
             connection.quote_table_name(field.to_s)
+          elsif Proc === field
+            field.call
           else
             field
           end