An empty transaction does not raise the `ReadOnlyError` if preventing writes

BEGIN transaction would cause COMMIT or ROLLBACK, so unless COMMIT and
ROLLBACK aren't treated as write queries as well as BEGIN, the
`ReadOnlyError` would be raised.

1 files changed, 10 insertions, 0 deletions

diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index 30e8a5f833..4938b6865f 100644
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -1538,4 +1538,14 @@ class BasicsTest < ActiveRecord::TestCase
       assert_queries(2) { Bird.where(name: "Bluejay").explain }
     end
   end
+
+  test "an empty transaction does not raise if preventing writes" do
+    ActiveRecord::Base.connection.while_preventing_writes do
+      assert_queries(2, ignore_none: true) do
+        Bird.transaction do
+          ActiveRecord::Base.connection.materialize_transactions
+        end
+      end
+    end
+  end
 end