Fix affected_rows for SQLite sql.active_record notifications

SQLite's connection.changes only reflects the number of rows affected by the last
DELETE/UPDATE/INSERT, and the number would not change for any other query. Therefore,
SELECT statements would have the affected row count of a previous query. To solve this,
we are now calculating the different between the total changes before and after the
query has been executed.

Co-authored-by: Hartley McGuire <[email protected]>

Author: jenshenny

activerecord/lib/active_record/connection_adapters/sqlite3/database_statements.rb

@@ -84,6 +84,8 @@ def internal_begin_transaction(mode, isolation)
           end
 
           def perform_query(raw_connection, sql, binds, type_casted_binds, prepare:, notification_payload:, batch: false)
+            total_changes_before_query = raw_connection.total_changes
+
             if batch
               raw_connection.execute_batch2(sql)
             elsif prepare
@@ -114,10 +116,10 @@ def perform_query(raw_connection, sql, binds, type_casted_binds, prepare:, notif
                 stmt.close
               end
             end
-            @last_affected_rows = raw_connection.changes
+            @affected_rows = raw_connection.total_changes - total_changes_before_query
             verified!
 
-            notification_payload[:affected_rows] = @last_affected_rows
+            notification_payload[:affected_rows] = @affected_rows
             notification_payload[:row_count] = result&.length || 0
             result
           end
@@ -129,7 +131,7 @@ def cast_result(result)
           end
 
           def affected_rows(result)
-            @last_affected_rows
+            @affected_rows
           end
 
           def execute_batch(statements, name = nil, **kwargs)

activerecord/test/cases/instrumentation_test.rb

@@ -165,14 +165,20 @@ def test_payload_affected_rows
         # INSERT ... RETURNING
         Book.insert_all!([{ name: "One" }, { name: "Two" }, { name: "Three" }, { name: "Four" }], returning: false)
 
+        Book.where(name: ["One", "Two", "Three"]).pluck(:id)
+
         Book.where(name: ["One", "Two", "Three"]).update_all(status: :published)
 
         Book.where(name: ["Three", "Four"]).delete_all
 
         Book.where(name: ["Three", "Four"]).delete_all
       end
 
-      assert_equal [4, 3, 2, 0], affected_row_values
+      assert_equal 4, affected_row_values.first
+      assert_not_equal affected_row_values.first, affected_row_values.second
+      assert_equal 3, affected_row_values.third
+      assert_equal 2, affected_row_values.fourth
+      assert_equal 0, affected_row_values.fifth
     end
 
     def test_no_instantiation_notification_when_no_records