Revert "Merge pull request rails#51987 from fatkodima/exists-and-loaded2"

This reverts commit c9075e3, reversing
changes made to a14eb2d.

Author: jhawthorn

activerecord/CHANGELOG.md

@@ -78,12 +78,6 @@
 
     *Nony Dutton*
 
-*   Optimize `Relation#exists?` when records are loaded and the relation has no conditions.
-
-    This can avoid queries in some cases.
-
-    *fatkodima*
-
 *   Add a `filter` option to `in_order_of` to prioritize certain values in the sorting without filtering the results
     by these values.
 

activerecord/lib/active_record/relation/finder_methods.rb

@@ -366,12 +366,6 @@ def exists?(conditions = :none)
 
       return false if !conditions || limit_value == 0
 
-      # Ignore if we have records which have saved changes since the load, because the
-      # relation can be a CollectionProxy and we updated the reference to the owner record.
-      if conditions == :none && loaded? && records.none?(&:saved_changes?)
-        return records.any?(&:persisted?)
-      end
-
       if eager_loading?
         relation = apply_join_dependency(eager_loading: false)
         return relation.exists?(conditions)

activerecord/test/cases/finder_test.rb

@@ -291,15 +291,15 @@ def test_exists_returns_false_with_false_arg
 
   def test_exists_with_loaded_relation
     topics = Topic.all.load
-    assert_no_queries do
+    assert_queries_match(/SELECT 1 AS one/i, count: 1) do
       assert_predicate topics, :exists?
     end
   end
 
   def test_exists_with_empty_loaded_relation
     Topic.delete_all
     topics = Topic.all.load
-    assert_no_queries do
+    assert_queries_match(/SELECT 1 AS one/i, count: 1) do
       assert_not_predicate topics, :exists?
     end
   end
@@ -310,7 +310,7 @@ def test_exists_with_loaded_relation_having_unsaved_records
     assert_not_empty posts
     posts.each(&:destroy)
 
-    assert_no_queries do
+    assert_queries_match(/SELECT 1 AS one/i) do
       assert_not_predicate posts, :exists?
     end
   end