Re: Calling Lisp from undo.c's record_* functions

[Stefan Monnier]

> In theory, therefore, we should already be safe? Or can the critical
> section be longer than a single function call to undo.c? Could the
> unsafe period cover several calls?

The problem is not in undo.c but in the fact that insdel.c calls
record_insert at a moment where Elisp code can't be run.  So the call to
record_insert would need to be moved.

But of course, in reality it's not the whole record_insert that needs to
be moved, only the run_undoable_change within it.

So if it's difficult to move record_insert to safe spot, maybe we should
take run_undoable_change out of it.

E.g. maybe we could call run_undoable_change from
prepare_to_modify_buffer instead.


        Stefan