chore(prototype): try jumping follower past leader via MovePath component exchange

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

mod/content/overtake_probe.script.tl

@@ -9,7 +9,9 @@ local TAG = "[overtake_probe] "
 local INTERVAL = 2.0
 local MAX_GAP = 40.0
 local MAX_REBUILDS = 0 -- rebuild disabled: proposals were silently rejected (segments kept their ids)
-local MAX_SETLINES = 5 -- EXPERIMENT: re-assign the follower to its own line + current stop to force a re-path
+local MAX_SETLINES = 0 -- set-line disabled: lanes ahead get re-planned by the engine anyway, no forced lane change
+local MAX_JUMPS = 3 -- EXPERIMENT: debug component exchange of MovePath with pathPos moved past the leader
+local JUMP_AHEAD = 15.0
 local elapsed = 0.0
 local ticks = 0
 
@@ -33,6 +35,7 @@ end
 local record Car
 	v : integer
 	pos : number
+	pos01 : number
 	speed : number
 	dir : boolean
 end
@@ -40,6 +43,7 @@ end
 local record ProbeState
 	rebuilds : integer
 	setlines : integer
+	jumps : integer
 	watch : {integer} -- vehicles involved in the last rebuild, flagged in later dumps
 end
 
@@ -97,17 +101,31 @@ local function setLine(v : integer)
 	api.cmd.sendCommand(api.cmd.makeVehicleSetLineCmd(v, tv.line, tv.stopIndex))
 end
 
+-- returns false when the target doesn't fit on the current edge (we don't jump across edges)
+local function jumpPast(follower : Car, leader : Car) : boolean, string
+	if leader.pos01 <= 0 then return false, "leader pos01=0" end
+	local len = leader.pos / leader.pos01
+	local target = leader.pos + JUMP_AHEAD
+	if target >= len then return false, string.format("target %.1f beyond edge length %.1f", target, len) end
+	local mp = api.engine.getComponent(follower.v, api.type.ComponentType.MOVE_PATH) as Engine.Component.MovePath
+	mp.dyn.pathPos.pos = target
+	mp.dyn.pathPos.pos01 = target / len
+	api.cmd.sendCommand(api.cmd.debug.makeComponentExchangeCmd(follower.v, mp as Engine.Component))
+	return true, string.format("pos %.1f -> %.1f (leader %.1f, edge length %.1f)", follower.pos, target, leader.pos, len)
+end
+
 local function dump(dt : number, state : GameScriptState<ProbeState>)
 	local st = state:get()
 	st.rebuilds = st.rebuilds or 0
 	st.setlines = st.setlines or 0
+	st.jumps = st.jumps or 0
 	st.watch = st.watch or {}
 	local watched : {integer : boolean} = {}
 	for _, w in ipairs(st.watch) do watched[w] = true end
 
 	local player = api.engine.util.getPlayer()
 	local vehicles = api.engine.getEntitiesWithComponent(api.type.ComponentType.TRANSPORT_VEHICLE, { requireOwnedByPlayer = player })
-	p(string.format("tick=%d dt=%s playerVehicles=%d rebuilds=%d setlines=%d", ticks, tostring(dt), #vehicles, st.rebuilds, st.setlines))
+	p(string.format("tick=%d dt=%s playerVehicles=%d rebuilds=%d setlines=%d jumps=%d", ticks, tostring(dt), #vehicles, st.rebuilds, st.setlines, st.jumps))
 
 	local byLane : {string : {Car}} = {}
 	local laneSeg : {string : integer} = {}
@@ -128,12 +146,12 @@ local function dump(dt : number, state : GameScriptState<ProbeState>)
 				local key = seg .. ":" .. edge.index
 				byLane[key] = byLane[key] or {}
 				laneSeg[key] = seg
-				table.insert(byLane[key], { v = v, pos = mp.dyn.pathPos.pos, speed = mp.dyn.speed, dir = dir })
+				table.insert(byLane[key], { v = v, pos = mp.dyn.pathPos.pos, pos01 = mp.dyn.pathPos.pos01, speed = mp.dyn.speed, dir = dir })
 			end
 		end
 	end
 
-	if st.rebuilds >= MAX_REBUILDS and st.setlines >= MAX_SETLINES then return end
+	if st.rebuilds >= MAX_REBUILDS and st.setlines >= MAX_SETLINES and st.jumps >= MAX_JUMPS then return end
 	for key, cars in pairs(byLane) do
 		for i = 1, #cars do
 			for j = 1, #cars do
@@ -143,6 +161,16 @@ local function dump(dt : number, state : GameScriptState<ProbeState>)
 				-- leader must be moving, otherwise it's a queue at a stop or junction, not a slow vehicle
 				if i ~= j and ahead and math.abs(b.pos - a.pos) < MAX_GAP and b.speed > 1.0 then
 					local seg = laneSeg[key]
+					if st.jumps < MAX_JUMPS then
+						local ok, why = jumpPast(a, b)
+						p(string.format("JUMP_TEST seg=%d follower=%d leader=%d sent=%s %s", seg, a.v, b.v, tostring(ok), why))
+						if ok then
+							st.jumps = st.jumps + 1
+							st.watch = { a.v, b.v }
+							state:set(st)
+							return -- one experiment per dump
+						end
+					end
 					if st.setlines < MAX_SETLINES then
 						local amp = api.engine.getComponent(a.v, api.type.ComponentType.MOVE_PATH) as Engine.Component.MovePath
 						p(string.format("SETLINE_TEST candidate seg=%d follower=%d (v=%.2f) leader=%d (v=%.2f) lanesAhead before: %s",