Using a dbgutil build:

1. Create this stub macro:

  Sub EmptyOn
  End Sub

2. In a new Calc document, assign it to a sheet's Formulas calculated action (right-click on the sheet's tab, select "Sheet Events")

3. Select an empty cell, and type into it:

  =1+1

=> debug assertion failed: back() called on empty deque

The failing code is inside '#if OSL_DEBUG_LEVEL > 0' of UndoManagerHelper_Impl::listActionLeft; it tries to read top of m_aContextAPIFlags, which is empty at this moment.

The reason is the processing sequence in ScViewFunc::EnterData, which first calls 'rFunc.EnterListAction( STR_UNDO_ENTERDATA );' before it processes the formula - at this moment, there's no listeners yet, so the action is not executed -> UndoManagerHelper_Impl::listActionEntered is not called; then it processes the formula and calls rFunc.SetFormulaCell - at which moment, a listener is added; and then it calls rFunc.EndListAction, which tries to call UndoManagerHelper_Impl::listActionLeft, which relies on UndoManagerHelper_Impl::listActionEntered being called previously.

But I don't know if simply checking if the stack is empty before the debugging code is OK - it looks hackish.

Eike: do you have an idea how to improve this?