How To Fix 28123 - Formal parameter &1 in table/function &2 is restrictable

SAP Error Message - Details

• Message type: E = Error

• Message class: 28 - Configuration

• Message number: 123

• Message text: Formal parameter &1 in table/function &2 is restrictable

What causes this issue?

The formal parameters which are used in tables/functions and are
accessed in object dependencies must all be single-value
characteristics. However, formal parameter &V1& for table/function &V2&
is restrictable.

System Response

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

How to fix this error?

Formal parameter &V1& for table/function &V2& cannot be used in
object dependencies. Correct your entry accordingly.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message 28123 - Formal parameter &1 in table/function &2 is restrictable ?

  The SAP error message 28123, which states "Formal parameter &1 in table/function &2 is restrictable," typically occurs in the context of ABAP programming when there is an issue with the definition of a formal parameter in a function module or method. This error indicates that a formal parameter is defined in a way that does not comply with the expected restrictions for that parameter type.
  Cause:
  The error can arise due to several reasons:
  
  Parameter Type Mismatch: The formal parameter is defined in a way that it is expected to be non-restrictable, but it is being treated as restrictable.
  Incorrect Definition: The parameter might be defined incorrectly in the function module or method signature.
  Inconsistent Usage: The way the parameter is used within the function or method does not align with its definition.
  
  Solution:
  To resolve this error, you can take the following steps:
  
  
  Check Parameter Definition: Review the definition of the formal parameter in the function module or method. Ensure that it is defined correctly according to the expected data type and usage.
  
  
  Adjust Parameter Attributes: If the parameter is intended to be restrictable, ensure that it is defined with the appropriate attributes. For example, if it should be an input/output parameter, make sure it is defined as such.
  
  
  Review Function Module/Method Logic: Look at the logic within the function module or method to ensure that the parameter is being used correctly. If it is being modified or expected to be modified, it should be defined as an output parameter.
  
  
  Consult Documentation: Refer to SAP documentation or the ABAP programming guidelines for more information on parameter definitions and restrictions.
  
  
  Testing: After making changes, test the function module or method to ensure that the error is resolved and that the functionality works as expected.
  
  
  Related Information:
  
  ABAP Documentation: Review the official SAP ABAP documentation for guidelines on defining parameters in function modules and methods.
  SAP Community: Engage with the SAP Community forums to see if others have encountered similar issues and how they resolved them.
  Debugging: Use the ABAP debugger to step through the code and identify where the parameter is causing issues.
  
  By following these steps, you should be able to identify the cause of the error and implement a solution to resolve it.