Loop

[BartAdv]

Seems to be really hard for me to nail it down.

Steps

This commit should make it easy to build and repro it:

5696a74

stack build && stack exec -- hackslash

Once it starts (it shows an empty window):

hit 'S'

watch the output with fine loop.

What I know about it

Basically, the goal was to write simple 'monster' that would react to change in monster positions, finding nearest one, and approaching it. This happens here:

      cmdApproach = traceEvent "cmdApproach" $
                    let eTarget = traceEvent "eTarget" $ fromJust <$> ffilter isJust (uncurry findTarget <$> attachPromptlyDyn pos (updated inputPositions))
                        ePath = init . fromJust <$> traceEvent "ePath" (ffilter isJust (uncurry (findPath inputLevel) <$> attachPromptlyDyn pos eTarget))
                    in CmdWalk <$> ePath

pos :: Dynamic t Coord -- monster position
inputPositions :: Dynamic t (Map MonsterID Coord) -- all monster positions

• findTarget does not find itself
• findPath uses astar library, currently whole grid is passable (I've stripped the code of freeablo dependencies)
• for some short paths, it doesn't loop.
• By looking at trace output, it doesn't look to me like it is the findPath which loops endlessly, so my hunch is that it could be some causality loop?