Ensure that preventing writes is invoked before `materialize_transactions` consistently

activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb

@@ -40,8 +40,6 @@ def execute(sql, name = nil)
         end
 
         def exec_query(sql, name = "SQL", binds = [], prepare: false)
-          materialize_transactions
-
           if without_prepared_statement?(binds)
             execute_and_free(sql, name) do |result|
               if result
@@ -62,8 +60,6 @@ def exec_query(sql, name = "SQL", binds = [], prepare: false)
         end
 
         def exec_delete(sql, name = nil, binds = [])
-          materialize_transactions
-
           if without_prepared_statement?(binds)
             execute_and_free(sql, name) { @connection.affected_rows }
           else
@@ -126,6 +122,8 @@ def exec_stmt_and_free(sql, name, binds, cache_stmt: false)
               raise ActiveRecord::ReadOnlyError, "Write query attempted while in readonly mode: #{sql}"
             end
 
+            materialize_transactions
+
             # make sure we carry over any changes to ActiveRecord::Base.default_timezone that have been
             # made since we established the connection
             @connection.query_options[:database_timezone] = ActiveRecord::Base.default_timezone

activerecord/test/cases/adapter_test.rb

@@ -166,9 +166,13 @@ class << @connection
     end
 
     def test_errors_when_an_insert_query_is_called_while_preventing_writes
-      assert_raises(ActiveRecord::ReadOnlyError) do
-        @connection.while_preventing_writes do
-          @connection.insert("INSERT INTO subscribers(nick) VALUES ('138853948594')")
+      assert_no_queries do
+        assert_raises(ActiveRecord::ReadOnlyError) do
+          @connection.while_preventing_writes do
+            @connection.transaction do
+              @connection.insert("INSERT INTO subscribers(nick) VALUES ('138853948594')", nil, false)
+            end
+          end
         end
       end
     end
@@ -176,9 +180,13 @@ def test_errors_when_an_insert_query_is_called_while_preventing_writes
     def test_errors_when_an_update_query_is_called_while_preventing_writes
       @connection.insert("INSERT INTO subscribers(nick) VALUES ('138853948594')")
 
-      assert_raises(ActiveRecord::ReadOnlyError) do
-        @connection.while_preventing_writes do
-          @connection.update("UPDATE subscribers SET nick = '9989' WHERE nick = '138853948594'")
+      assert_no_queries do
+        assert_raises(ActiveRecord::ReadOnlyError) do
+          @connection.while_preventing_writes do
+            @connection.transaction do
+              @connection.update("UPDATE subscribers SET nick = '9989' WHERE nick = '138853948594'")
+            end
+          end
         end
       end
     end
@@ -186,9 +194,13 @@ def test_errors_when_an_update_query_is_called_while_preventing_writes
     def test_errors_when_a_delete_query_is_called_while_preventing_writes
       @connection.insert("INSERT INTO subscribers(nick) VALUES ('138853948594')")
 
-      assert_raises(ActiveRecord::ReadOnlyError) do
-        @connection.while_preventing_writes do
-          @connection.delete("DELETE FROM subscribers WHERE nick = '138853948594'")
+      assert_no_queries do
+        assert_raises(ActiveRecord::ReadOnlyError) do
+          @connection.while_preventing_writes do
+            @connection.transaction do
+              @connection.delete("DELETE FROM subscribers WHERE nick = '138853948594'")
+            end
+          end
         end
       end
     end