Added isObsolete and setObsolete functions to QUndoCommand that signifies
a command is not functional. This is useful for when two commands are
merged in such a way that the merged command does nothing. Another
particular use is with networking commands in which the command fails
due to connection issues. The command is considered obsolete because the
undo/redo functions do nothing since the connection failed.
This property is checked in QUndoStack::push(), QUndoStack::undo(),
QUndoStack::redo(), and QUndoStack::setIndex(). The obsolete flag is
checked after QUndoCommand::undo(), QUndoCommand::redo(), and
QUndoCommand::mergeWith() is called where applicable. This allows the
user to set the obsolete flag within the QUndoCommand class and it will
be deleted directly afterwards.
Task-number: QTBUG-54970
Change-Id: Ia8e962ff3aa16515e8f9e2180aee5e1d726d5ba3
Reviewed-by: David Faure <david.faure@kdab.com>
00ad7bd5a4