Yeah, in 0.7.12, digger-digger cancelling requires an assignment during 3/16 of the old digger's frames. There's a chance that a passing walker, during his 9-11 frames of overlap with the old digger, won't be in the correct spot to cancel. I accept that the first post didn't describe this fiddliness.
With geoo offering to work on re-coverage, I'm leaning to accept the proposal. The main counter-argument was the workload.
Another idea would be to make digger-digger cancelling easier instead of impossible, but I'm not leaning as strongly towards that. I'll leave it open for 1-2 days.
I'm also considering to make the digger
more lenient with steel. The mask is 9 lo-res pixels wide. 0.7.12 cancels when one of the 7 innermost lo-res pixels is steel. In particular, these diggers hits steel and won't remove anything:
Proposal for steel sensitivity: I'm considering to loosen the steel check. Instead of the 7 innermost lo-res pixels, check only the 5 innermost for steel.
Or maybe even the 3 innermost only, that would be closest to 0.6 physics. But Proxima suggests that would be too lenient, intuitively expecting the 3-innermost-checking digger to choke on the steel:
No replays would break from the more lenient steel check: I tested with both 5-innermost and 3-innermost. If there are possible backroutes in levels from this lenience, those backroutes would have already been possible in 0.6, which effectively had a 3-innermost steel check as long as all steel was to one side of the digger.
-- Simon