How To Fix /IWPGW/TGW_TCM_MSG008 - Return parameter expected to be a structure type

SAP Error Message - Details

• Message type: E = Error

• Message class: /IWPGW/TGW_TCM_MSG -

• Message number: 008

• Message text: Return parameter expected to be a structure type

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message /IWPGW/TGW_TCM_MSG008 - Return parameter expected to be a structure type ?

  The SAP error message /IWPGW/TGW_TCM_MSG008 indicates that a return parameter in a function module or method is expected to be a structure type, but it is not. This error typically occurs in the context of SAP Gateway services, where the expected data format does not match the actual data format being returned.
  Cause:
  
  Incorrect Data Type: The return parameter defined in the service implementation is not of the expected structure type. For example, it might be defined as a simple data type (like a string or integer) instead of a structured type.
  Service Definition Mismatch: The service definition in the SAP Gateway might not match the implementation. If the service expects a structured return type but the implementation returns a different type, this error will occur.
  Model Issues: If you are using an OData model, the model might not be correctly defined to match the expected structure.
  
  Solution:
  
  
  Check Function Module/Method Definition: Review the function module or method that is being called. Ensure that the return parameter is defined as a structure type. If it is not, modify it to be a structure type that matches the expected output.
  
  
  Adjust Service Implementation: If you are implementing a service, ensure that the return type in your implementation matches the expected structure defined in the service metadata. You may need to adjust the code to return a structured type.
  
  
  Update Service Definition: If the service definition is incorrect, you may need to update it in the SAP Gateway Service Builder (transaction code SEGW). Ensure that the return type is correctly defined as a structure.
  
  
  Regenerate the Service: After making changes, regenerate the service to ensure that the changes are reflected in the service metadata. This can be done in the Service Builder.
  
  
  Test the Service: After making the necessary changes, test the service again to ensure that the error is resolved.
  
  
  Related Information:
  
  
  Transaction Codes: 
  
  SE80: Object Navigator, to check and modify function modules or classes.
  SEGW: Service Builder, to manage OData services.
  
  
  
  Documentation: Refer to SAP documentation on OData services and Gateway development for more detailed guidance on defining structures and return types.
  
  
  Debugging: If the issue persists, consider using the debugger to trace the execution and see what data types are being passed around, which can help identify where the mismatch occurs.
  
  
  By following these steps, you should be able to resolve the error message /IWPGW/TGW_TCM_MSG008 and ensure that your SAP Gateway service is functioning correctly.