Relation#inspect handles doesn't perform a new query on an already-loaded relation

2 files changed, 16 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb
index 0d1c9ef3e5..a39328b89b 100644
--- a/activerecord/lib/active_record/relation.rb
+++ b/activerecord/lib/active_record/relation.rb
@@ -515,7 +515,10 @@ module ActiveRecord
     end
 
     def inspect
-      entries = limit([limit_value, 11].compact.min).map(&:inspect)
+      limit   = [limit_value, 11].compact.min
+      entries = loaded? ? to_a.take(limit) : limit(limit)
+
+      entries.map!(&:inspect)
       entries[10] = '...' if entries.size == 11
 
       "#<#{self.class.name} [#{entries.join(', ')}]>"
diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index bdf14e0a85..8713b8d5e4 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -1317,8 +1317,19 @@ class RelationTest < ActiveRecord::TestCase
     assert_equal "#<ActiveRecord::Relation [#{Post.limit(2).map(&:inspect).join(', ')}]>", relation.inspect
   end
 
-  test "relations limits the records in #inspect at 10" do
+  test "relations limit the records in #inspect at 10" do
     relation = Post.limit(11)
     assert_equal "#<ActiveRecord::Relation [#{Post.limit(10).map(&:inspect).join(', ')}, ...]>", relation.inspect
   end
+
+  test "already-loaded relations don't perform a new query in #inspect" do
+    relation = Post.limit(2)
+    relation.to_a
+
+    expected = "#<ActiveRecord::Relation [#{Post.limit(2).map(&:inspect).join(', ')}]>"
+
+    assert_no_queries do
+      assert_equal expected, relation.inspect
+    end
+  end
 end