How To Fix FL173 - Adding exceptions is not allowed; function module belongs to Basis

SAP Error Message - Details

• Message type: E = Error

• Message class: FL - Function Builder messages

• Message number: 173

• Message text: Adding exceptions is not allowed; function module belongs to Basis

What causes this issue?

The function module that you are changing belongs to the Basis
interface.

System Response

Incompatible changes are not allowed. This action is terminated.

How to fix this error?

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message FL173 - Adding exceptions is not allowed; function module belongs to Basis ?

  The SAP error message FL173, which states "Adding exceptions is not allowed; function module belongs to Basis," typically occurs when you are trying to add exception handling to a function module that is part of the SAP Basis system. Function modules in the Basis layer are often designed to be stable and reliable, and SAP restricts modifications to these modules to maintain system integrity.
  Cause:
  
  Function Module Restrictions: The function module you are trying to modify is a standard SAP function module that is part of the Basis layer. SAP restricts changes to these modules to prevent instability in the system.
  Modification Attempts: You may be attempting to add exception handling (like TRY...CATCH blocks) to a function module that is not designed to allow such modifications.
  
  Solution:
  
  Avoid Modifying Basis Function Modules: Instead of trying to modify the function module directly, consider using it as is. If you need to handle exceptions, you can do so in the calling program or function module.
  Create a Wrapper Function Module: If you need to add custom exception handling, create a new function module that calls the original Basis function module. In your wrapper, you can implement the necessary exception handling.
  Check for Alternatives: Look for alternative function modules or methods that may provide the functionality you need without requiring modifications to the Basis function modules.
  Consult SAP Documentation: Review the SAP documentation for the specific function module to understand its intended use and any existing exception handling mechanisms.
  
  Related Information:
  
  SAP Notes: Check SAP Notes for any specific guidance or updates related to the function module you are working with. SAP Notes often provide insights into known issues and best practices.
  SAP Community: Engage with the SAP Community forums to see if others have encountered similar issues and what solutions they have implemented.
  ABAP Development Guidelines: Familiarize yourself with SAP's ABAP development guidelines, which provide best practices for handling exceptions and working with function modules.
  
  By following these guidelines, you can effectively manage the error message FL173 and ensure that your SAP development adheres to best practices while maintaining system stability.