The commit diff shows critical changes in the Product::update method where multiple SQL query parameters (including desiredstock) were modified to add (int) type casting. The original vulnerable code directly embedded user-controlled $this->desiredstock into the SQL query without validation, allowing arbitrary SQL execution. The patch explicitly addresses this by enforcing integer casting, confirming this was the injection vector. The function's role in building UPDATE queries with user inputs makes it the clear entry point for this SQLi vulnerability.