Rule

If a method uses system resources (such as files, sockets, streams, etc), the code MUST be wrapped with a try block and the corresponding finally block. In the finally sections, all resources SHOULD be properly released.

Reason

Source: Magento Technical Guidelines.

Implementation

• Subscribe to T_STRING token.
• Prepare the list of build in PHP functions that use resources or alternatively functions prefixes (stream_, socket_, etc)
• Check if token content is in_array of system functions.
• Raise a warning if no outer try statement detected.