Inside a routine, commands recorded no undo step (the routine becomes
one when it ends), so U inside a routine took back the step from before
the routine: after drawing a line D, ERASE B then U in one routine
brought B back and removed D.
As AutoCAD 2024 does (accoreconsole, the drawing read back after one
routine), U inside a routine now takes back the routine's last command,
with what the routine did after it (entdel, entmake); U again, UNDO n
and REDO go on through its commands. With none left, U takes back the
drawing's step before the routine, as before, and the routine's step
then starts from there. Once the routine ends it is still one undo step.
The routine's steps live in the session's LISP state (RoutineSteps), not
in the drawing's undo stack, so a long routine doesn't push the drawing's
earlier steps out. A command inside the routine ends what REDO could
bring back; UNDO Control One and None apply. DocState::swap_in is the
one restore step undo, redo and the routine share.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
panic_hunt runs every command in a fresh session and fails on real panics. The guard now covers the steps after a command, so a late panic restores the drawing instead of ending the app.
