[Audacity-devel] Bug in ModifyState?

[Markus M. <me...@me...>]

Hi everyone,

this is what I found when looking into Daniel James bug report (undo
state not updated when changing track gain control):

Actually, UndoManager::ModifyState _is_ called when the track gain
control is adjusted. I have checked this by adding trace printf's into
the function. But: The UndoManager doesn't know that the state has been
modified when ModifyState is called! (Look at the implementation of
UnsavedChanges() to see why).

Obvious solution would be to explicitely add a flag which is set when
ModifyState or PushState is called, but I request your comments because
I'm afraid I must have understood something wrong here.

There is also a second problem, which will only materialize when the
problem mentioned above has been fixed: Right after a file has been
loaded some function in the TrackPanel class is called to set the
selection to the last value stored in the .AUP file. This already causes
ModifyState to be called (it shouldn't, because no user interaction has
taken place). Hence, when a call to ModifyState would (correctly) cause
UnsavedChanged to return true, this would mean that right after a file
has been loaded it is already marked as "modified", which is wrong.


Markus