Merge pull request rails#52015 from maniSHarma7575/51991-pluck-column…

…s-should-correctly-casts-types-when-using-postgresql

[FIX] Pluck columns should correctly casts types when using postgresql

activerecord/lib/active_record/relation/calculations.rb

@@ -604,7 +604,7 @@ def type_cast_pluck_values(result, columns)
               model.attribute_types.fetch(name = result.columns[i]) do
                 join_dependencies ||= build_join_dependencies
                 lookup_cast_type_from_join_dependencies(name, join_dependencies) ||
-                  result.column_types[name] || Type.default_value
+                  result.column_types[i] || Type.default_value
               end
           end
         end

activerecord/test/cases/calculations_test.rb

@@ -847,6 +847,10 @@ def test_pluck_type_cast
     assert_equal [ topic.approved ], relation.pluck(:approved)
     assert_equal [ topic.last_read ], relation.pluck(:last_read)
     assert_equal [ topic.written_on ], relation.pluck(:written_on)
+    assert_equal(
+      [[topic.written_on, topic.replies_count]],
+      relation.pluck("min(written_on)", "min(replies_count)")
+    )
   end
 
   def test_pluck_type_cast_with_conflict_column_names
@@ -1224,22 +1228,13 @@ def test_pluck_functions_with_alias
   end
 
   def test_pluck_functions_without_alias
-    expected = if current_adapter?(:PostgreSQLAdapter)
-      # PostgreSQL returns the same name for each column in the given query, so each column is named "coalesce"
-      # As a result Rails cannot accurately type cast each value.
-      # To work around this, you should use aliases in your select statement (see test_pluck_functions_with_alias).
-      [
-        ["1", "The First Topic"], ["2", "The Second Topic of the day"],
-        ["3", "The Third Topic of the day"], ["4", "The Fourth Topic of the day"],
-        ["5", "The Fifth Topic of the day"]
-      ]
-    else
-      [
-        [1, "The First Topic"], [2, "The Second Topic of the day"],
-        [3, "The Third Topic of the day"], [4, "The Fourth Topic of the day"],
-        [5, "The Fifth Topic of the day"]
-      ]
-    end
+    expected = [
+      [1, "The First Topic"],
+      [2, "The Second Topic of the day"],
+      [3, "The Third Topic of the day"],
+      [4, "The Fourth Topic of the day"],
+      [5, "The Fifth Topic of the day"]
+    ]
 
     assert_equal expected, Topic.order(:id).pluck(
       Arel.sql("COALESCE(id, 0)"),