How To Fix FL034 - No preceding dynpro in internal stack

SAP Error Message - Details

• Message type: E = Error

• Message class: FL - Function Builder messages

• Message number: 034

• Message text: No preceding dynpro in internal stack

What causes this issue?

All Function Builder screens accessed in a single session are stored in
an internal stack. Objects can be removed from this internal stack
using SCREEN according to the LIFO (last in first out) principle.
The internal stack is currently empty.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message FL034 - No preceding dynpro in internal stack ?

  The SAP error message FL034: No preceding dynpro in internal stack typically occurs in the context of SAP GUI programming, particularly when dealing with screen navigation and dialog programming. This error indicates that the system is trying to navigate to a screen (dynpro) that does not have a valid preceding screen in the internal stack. This can happen for several reasons, including:
  Causes:
  
  
  Incorrect Navigation Logic: The program may be trying to call a screen without having a valid previous screen in the stack. This can happen if the program logic is flawed or if there are missing calls to previous screens.
  
  
  Screen Flow Issues: If the flow of screens is not properly defined or if there are jumps in the screen sequence that do not maintain the expected stack, this error can occur.
  
  
  Program Termination: If a program terminates unexpectedly or if there is an unhandled exception, it may leave the internal stack in an inconsistent state.
  
  
  Calling a Screen from a Non-Dynpro Context: Attempting to call a dynpro from a context that does not support it (like a background job or a non-dialog program) can lead to this error.
  
  
  Solutions:
  
  
  Check Screen Navigation: Review the program code to ensure that the navigation between screens is correctly implemented. Make sure that every screen call is preceded by a valid screen context.
  
  
  Use LEAVE TO SCREEN Correctly: Ensure that you are using the LEAVE TO SCREEN statement correctly. It should be used to navigate to a new screen only when there is a valid preceding screen.
  
  
  Debugging: Use the debugger to trace the program execution and check the internal stack. This can help identify where the navigation is failing.
  
  
  Error Handling: Implement proper error handling to manage unexpected terminations or exceptions that could disrupt the screen flow.
  
  
  Review Module Pool Programs: If you are working with module pool programs, ensure that the flow logic is correctly defined in the PBO (Process Before Output) and PAI (Process After Input) modules.
  
  
  Check for Unintended Exits: Look for any EXIT or LEAVE statements that might be causing the program to exit unexpectedly before reaching the intended screen.
  
  
  Related Information:
  
  SAP Documentation: Refer to SAP's official documentation for more details on screen programming and navigation.
  SAP Community: Engage with the SAP Community forums to see if others have encountered similar issues and how they resolved them.
  ABAP Development Guidelines: Follow best practices for ABAP development, especially regarding screen handling and navigation.
  
  By addressing the above points, you should be able to resolve the FL034 error and ensure proper screen navigation in your SAP application.