In the last weeks, I several times observed that the undo funktionality did not work.
Today I had the puzzle 2229 open. I then opened 2239 for the first time. Now the undo graph was empty (OK). When you then do a shake all until the score has changed and then stop it, the Undo graph stays empty. Change some parts of the initial loop to a helix and idealize them. Score changes. Undo still empty. Hotkey ctrl Z does not work.
I am running V18-20221205-f2e450e756-win_x64-devprev on Win10.
I've seen the same problem. Turns out it may have an easy fix.
Some recipes issue the command undo.SetUndo(false) when they start. This command enables one-step undo, so a single control-z can revert everything a recipe did.
It looks like a recipe should also set undo.SetUndo(true) at the end. I previously thought this was only necessary if you wanted the undo system to capture an important change mid-recipe. But maybe I was wrong, or maybe the behavior has changed with the new system.
It appears that undo remains disabled if a recipe terminates without issuing undo.SetUndo(true). The recipe Banded Worm Pairs Inf Filt 1.4.9 has this problem. Previous versions included undo.SetUndo(true), but version 1.4.9 does not.
The recipe Reset undo issues the undo.SetUndo(true) command. This recipe may resolve the issue.
I'll work on an update to BWP IF 1.4.9, which also has a couple of other loose ends.
A little testing on Oldit seems to show that undo.SetUndo(true) was not required. The undo function appears to be automatically re-enabled when a recipe ends.
