Unlock menu after failed join; remove contact damage; cover clean disconnects

A failed connection left the connect buttons disabled forever. _show_menu()
returned early when a menu already existed, so the set_busy(false) that
re-enables them never ran on the way back from _abort_connect -- the player was
locked out of both joining and hosting with no way out but a restart. Also
guards against a second attempt stacking on an in-flight one.

Contact damage is gone as a concept: nothing in this game hurts you by touching
it, because every threat should be a bullet you can see and dodge. The Stalker
walked at you and dealt contact damage and nothing else, so it now carries a
point-blank shotgun instead -- five pellets, 62 degrees, 18-tick lifetime for
about 78px of reach, so it still has to close and leaves nothing lingering.
tests/unit/test_content.gd asserts every hostile enemy has an emitter, so a new
enemy cannot quietly reintroduce the mechanic.

The menu's "Disconnect" DOES get the anti-cheese protection -- verified, not
assumed. It calls Net.shutdown(), the socket closes, and the server takes the
same linkdead path as a SIGKILL, because the channel is keyed on the socket
closing rather than on how it closed. Made permanent: a --leave-after bot flag
and two smoke assertions covering the polite exit alongside the hard kill, so a
future "clean leave" message that skipped the channel would fail a test. The
menu now says so out loud in a dungeon -- the mechanic only reads as fair if
the cost is known before clicking.

103 tests, 12 smoke assertions; check.sh, test.sh and smoke.sh all pass.

CLAUDE.md

@@ -116,6 +116,9 @@ ticks in milliseconds with no SceneTree.
   dead zone where the server rejects everything and the client never notices —
   the ship and the authoritative position separate permanently. Pinned by
   `tests/unit/test_input_lead.gd`.
+- **No contact damage.** Every enemy threatens through bullets only; touching
+  one is harmless. `tests/unit/test_content.gd` enforces that every hostile has
+  an emitter.
 - **No i-frames.** Every bullet that touches a player lands; `spawn_grace` is
   the only invulnerable state. Do not reintroduce post-hit immunity — it makes
   dense patterns safer than sparse ones.

docs/NETCODE.md

@@ -104,6 +104,39 @@ Two defences now:
 `tools/diag_prediction.gd` injects a +14 tick drift mid-run and asserts the gap
 returns to normal; it exits non-zero if it does not.
 
+### Every exit runs the same channel
+
+There is deliberately no "I am leaving cleanly" message. The escape channel is
+keyed on the socket closing, so all four ways out converge on it:
+
+| Route | Path |
+| --- | --- |
+| Hold F | `BTN_ESCAPE` -> channel |
+| Menu -> "Return to hub" | synthesises a held `BTN_ESCAPE` -> channel |
+| Menu -> "Disconnect to menu" | `Net.shutdown()` -> socket close -> `linkdead` -> channel |
+| Killing the process / pulling the cable | socket close -> `linkdead` -> channel |
+
+The last two are the same server-side code path, and `tools/smoke.sh` asserts
+both: one bot is SIGKILLed mid-dungeon, another calls the same `Net.shutdown()`
+the menu button calls. Adding a clean-leave message that skipped the channel
+would break that test, which is the point of having it.
+
+The menu says so out loud when you are in a dungeon -- the mechanic only reads
+as fair if the player knows the cost before clicking.
+
+## No contact damage
+
+Nothing hurts you by touching it. Every threat is a bullet you can see and
+dodge, which is the contract the genre runs on; an enemy that damages you for
+occupying the same space is an unavoidable, unreadable hit.
+
+The Stalker used to be exactly that -- it walked at you and dealt contact
+damage. It now carries a point-blank shotgun instead: five pellets, 62 degrees,
+and an 18-tick lifetime that gives it about 78px of reach, so it still has to
+close the distance and still leaves nothing lingering in the arena.
+`tests/unit/test_content.gd` asserts that every hostile enemy has at least one
+emitter, so a new enemy cannot quietly reintroduce the mechanic.
+
 ## No invulnerability frames
 
 A hit grants no immunity — every bullet that touches you deals its damage. In a

resources/enemies/drifter.tres

@@ -17,7 +17,6 @@ damage = 10
 script = ExtResource("3_e6oj1")
 id = &"drifter"
 display_name = "Drifter"
-contact_damage = 8
 speed = 55.0
 emitters = Array[ExtResource("1_801wv")]([SubResource("Resource_vpd04")])
 pattern_loop_ticks = 120

resources/enemies/dummy.tres

@@ -9,6 +9,5 @@ id = &"dummy"
 display_name = "Target Dummy"
 max_hp = 100000
 radius = 20.0
-contact_damage = 0
 move = 0
 visual = 3

resources/enemies/stalker.tres

@@ -1,16 +1,29 @@
 [gd_resource type="Resource" script_class="EnemyDef" format=3]
 
-[ext_resource type="Script" path="res://src/sim/patterns/bullet_emitter.gd" id="1_dkoo8"]
+[ext_resource type="Script" path="res://src/sim/patterns/bullet_emitter.gd" id="1_t1lyl"]
-[ext_resource type="Script" path="res://src/actors/enemies/enemy_def.gd" id="2_t1lyl"]
+[ext_resource type="Script" path="res://src/sim/patterns/aimed_spread_emitter.gd" id="2_e7xon"]
+[ext_resource type="Script" path="res://src/actors/enemies/enemy_def.gd" id="3_ehenj"]
+
+[sub_resource type="Resource" id="Resource_tpjo4"]
+script = ExtResource("2_e7xon")
+spread_deg = 62.0
+muzzle_offset = 10.0
+interval = 45
+speed = 260.0
+radius = 6.0
+lifetime = 18
+damage = 14
+kind = 3
 
 [resource]
-script = ExtResource("2_t1lyl")
+script = ExtResource("3_ehenj")
 id = &"stalker"
 display_name = "Stalker"
 max_hp = 30
 radius = 12.0
-contact_damage = 16
 move = 3
 speed = 95.0
 retarget_interval = 20
 visual = 2
+emitters = Array[ExtResource("1_t1lyl")]([SubResource("Resource_tpjo4")])
+pattern_loop_ticks = 45

resources/enemies/turret.tres

@@ -17,7 +17,6 @@ id = &"turret"
 display_name = "Turret"
 max_hp = 70
 radius = 16.0
-contact_damage = 0
 move = 0
 speed = 0.0
 visual = 1

src/actors/enemies/enemy_def.gd

@@ -21,7 +21,6 @@ enum Move {
 @export var display_name: String = "Drone"
 @export var max_hp: int = 40
 @export var radius: float = 14.0
-@export var contact_damage: int = 10
 @export var move: Move = Move.DRIFT
 @export var speed: float = 60.0
 ## ORBIT radius, or STRAFE preferred distance.

src/content/content.gd

@@ -41,7 +41,6 @@ static func drifter() -> EnemyDef:
 	d.display_name = "Drifter"
 	d.max_hp = 40
 	d.radius = 14.0
-	d.contact_damage = 8
 	d.move = EnemyDef.Move.DRIFT
 	d.speed = 55.0
 	d.visual = 0
@@ -68,7 +67,6 @@ static func turret() -> EnemyDef:
 	d.display_name = "Turret"
 	d.max_hp = 70
 	d.radius = 16.0
-	d.contact_damage = 0
 	d.move = EnemyDef.Move.STATIC
 	d.speed = 0.0
 	d.visual = 1
@@ -88,18 +86,40 @@ static func turret() -> EnemyDef:
 	return d
 
 
-## Walks at you and does nothing else. The pressure enemy.
+## Walks at you and fires a point-blank burst. The pressure enemy.
+##
+## It used to deal contact damage and nothing else. Nothing in this game hurts
+## you by touching you -- every threat is a bullet you can see coming and dodge,
+## which is the whole contract of the genre. So the Stalker's melee is a
+## shotgun with a deliberately tiny lifetime: ~78px of travel, which only
+## threatens once it has closed the distance, and leaves nothing lingering in
+## the arena afterwards.
 static func stalker() -> EnemyDef:
 	var d := EnemyDef.new()
 	d.id = ENEMY_STALKER
 	d.display_name = "Stalker"
 	d.max_hp = 30
 	d.radius = 12.0
-	d.contact_damage = 16
 	d.move = EnemyDef.Move.APPROACH
 	d.speed = 95.0
 	d.retarget_interval = 20
 	d.visual = 2
+	d.pattern_loop_ticks = 45
+
+	var lunge := AimedSpreadEmitter.new()
+	lunge.start_tick = 0
+	lunge.interval = 45
+	lunge.count = 5
+	lunge.spread_deg = 62.0
+	lunge.speed = 260.0
+	lunge.radius = 6.0
+	lunge.damage = 14
+	# 18 ticks at 260 u/s is about 78px of reach -- shorter than the muzzle-to-
+	# player distance at any range you would call "not point blank".
+	lunge.lifetime = 18
+	lunge.muzzle_offset = 10.0
+	lunge.kind = SimConfig.KIND_HEAVY
+	d.emitters = [lunge]
 	return d
 
 
@@ -110,7 +130,6 @@ static func dummy() -> EnemyDef:
 	d.display_name = "Target Dummy"
 	d.max_hp = 100000
 	d.radius = 20.0
-	d.contact_damage = 0
 	d.move = EnemyDef.Move.STATIC
 	d.visual = 3
 	return d

src/core/game_opts.gd

@@ -17,6 +17,11 @@ static var bot_client: bool = false
 static var autoquit_ticks: int = 0
 ## Skip the menu and connect straight away. Implied by --bot.
 static var autojoin: bool = false
+## Bot harness only: gracefully disconnect after this many ticks inside a
+## dungeon, the way the in-game menu's "Disconnect" button does. Lets the smoke
+## test cover the clean-exit path as well as a hard kill -- both must be caught
+## by the same server-side escape channel.
+static var bot_leave_after: int = 0
 ## Skip the menu and start a listen server (host + local player).
 static var listen: bool = false
 ## Server-side dev switch: new dungeons open straight onto the boss, skipping
@@ -38,6 +43,10 @@ static func parse(argv: PackedStringArray = PackedStringArray()) -> void:
 				autojoin = true
 			"--join":
 				autojoin = true
+			"--leave-after":
+				i += 1
+				if i < argv.size():
+					bot_leave_after = int(argv[i])
 			"--listen":
 				listen = true
 			"--boss-rush":

src/main.gd

@@ -58,13 +58,17 @@ func _run_dedicated_server() -> void:
 
 
 func _show_menu() -> void:
-	if _menu != null:
-		return
 	_clear_game()
+	if _menu == null:
 		_menu = preload("res://src/ui/main_menu.gd").new()
 		_menu.join_requested.connect(_join)
 		_menu.host_requested.connect(_host_and_play)
 		add_child(_menu)
+	# Unconditional, and the reason this is not an early-return when the menu
+	# already exists: a failed connection returns here with the buttons still
+	# disabled from _menu_busy(true), and skipping this left the player locked
+	# out of both joining and hosting with no way back short of a restart.
+	_menu.set_busy(false)
 
 
 ## Note what this deliberately does NOT do: enter the game. Net.join() only
@@ -74,6 +78,8 @@ func _show_menu() -> void:
 ## acknowledged them. The game scene now waits for the server to actually place
 ## us in an instance.
 func _join(address: String, port: int) -> void:
+	if _connecting:
+		return
 	GameOpts.host_address = address
 	GameOpts.port = port
 	if Net.join(address, port) != OK:
@@ -106,7 +112,7 @@ func _abort_connect(reason: String) -> void:
 		get_tree().quit(1)
 		return
 	Net.shutdown()
-	_show_menu()
+	_show_menu()   # re-enables the connect buttons
 	_menu_status(reason)
 
 
@@ -114,6 +120,8 @@ func _abort_connect(reason: String) -> void:
 ## connected over loopback. The client takes no shortcuts because of it -- it
 ## still only sends input and still only learns outcomes from snapshots.
 func _host_and_play(port: int) -> void:
+	if _connecting:
+		return
 	if Net.host(port) != OK:
 		_menu_status(Net.last_error)
 		return

src/net/client_runtime.gd

@@ -65,6 +65,7 @@ var snap_prev: Dictionary = {}
 var snap_curr: Dictionary = {}
 var _interp: float = 0.0
 var _bot_tick: int = 0
+var _dungeon_ticks: int = 0
 
 
 func _ready() -> void:
@@ -104,6 +105,19 @@ func _physics_process(delta: float) -> void:
 
 	world.step()
 	_interp = minf(_interp + delta * float(SimConfig.TICK_RATE) / float(SimConfig.SNAPSHOT_INTERVAL), 1.0)
+	_maybe_bot_leave()
+
+
+## Bot harness: quit cleanly mid-run so the smoke test proves a polite
+## disconnect is caught by the same channel a SIGKILL is. Deferred because
+## Net.shutdown() frees this node.
+func _maybe_bot_leave() -> void:
+	if GameOpts.bot_leave_after <= 0 or instance_kind != Protocol.InstanceKind.DUNGEON:
+		return
+	_dungeon_ticks += 1
+	if _dungeon_ticks == GameOpts.bot_leave_after:
+		GameLog.info("client", "BOT_GRACEFUL_LEAVE")
+		Net.shutdown.call_deferred()
 
 
 # --- Input ------------------------------------------------------------------

src/net/server_runtime.gd

@@ -108,8 +108,8 @@ func on_peer_disconnected(peer_id: int) -> void:
 		return
 	if inst.kind == Protocol.InstanceKind.DUNGEON:
 		inst.detach_peer(peer_id)
-		GameLog.info("server", "peer %d dropped in instance %d, channelling out"
+		GameLog.info("server", "peer %d '%s' dropped in instance %d, channelling out"
-			% [peer_id, inst.id])
+			% [peer_id, peer_names.get(peer_id, "?"), inst.id])
 		_broadcast_roster()
 		return
 	inst.remove_peer(peer_id)

src/sim/sim_world.gd

@@ -140,7 +140,6 @@ func step() -> void:
 		_step_boss()
 		pool.step()
 		_resolve_bullet_hits()
-		_resolve_contact_damage()
 		_emit_spawn_events()
 	else:
 		# Replica: bullets only. Actor state arrives in snapshots.
@@ -352,17 +351,6 @@ func _resolve_bullet_hits() -> void:
 				_kill_bullet(i)
 
 
-func _resolve_contact_damage() -> void:
-	for e in enemies.values():
-		if not e.alive or e.def.contact_damage <= 0:
-			continue
-		for p in players.values():
-			if not p.alive or p.invulnerable():
-				continue
-			if Movement.circles_overlap(e.pos, e.def.radius, p.pos, SimConfig.PLAYER_RADIUS):
-				_damage_player(p, e.def.contact_damage)
-
-
 ## Bullets removed early must be announced -- clients cannot derive a hit.
 func _kill_bullet(slot: int) -> void:
 	events.append({"t": SimEvent.Type.BULLET_DESPAWN, "uid": pool.uid[slot]})

src/ui/game_menu.gd

@@ -12,6 +12,9 @@ signal disconnect_requested
 
 var _panel: VBoxContainer
 var _hub_button: Button
+var _disconnect_button: Button
+var _note: Label
+var _in_dungeon: bool = false
 var _open: bool = false
 
 
@@ -42,17 +45,18 @@ func _ready() -> void:
 	title.add_theme_font_size_override("font_size", 26)
 	_panel.add_child(title)
 
-	var note := Label.new()
+	_note = Label.new()
-	note.text = "The world keeps running. You are not safe here."
+	_note.add_theme_font_size_override("font_size", 12)
-	note.add_theme_font_size_override("font_size", 12)
+	_note.add_theme_color_override("font_color", Color(1.0, 0.7, 0.5))
-	note.add_theme_color_override("font_color", Color(1.0, 0.7, 0.5))
+	_note.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
-	_panel.add_child(note)
+	_note.custom_minimum_size = Vector2(320.0, 0.0)
+	_panel.add_child(_note)
 
 	_hub_button = _button("Return to hub", func() -> void:
 		return_to_hub_requested.emit()
 		close())
 	_button("Resume", func() -> void: close())
-	_button("Disconnect to menu", func() -> void:
+	_disconnect_button = _button("Disconnect to menu", func() -> void:
 		disconnect_requested.emit()
 		close())
 	_button("Quit game", func() -> void: get_tree().quit())
@@ -100,4 +104,19 @@ func is_open() -> bool:
 
 ## The hub button is meaningless when you are already in the hub.
 func set_in_dungeon(in_dungeon: bool) -> void:
+	if in_dungeon == _in_dungeon and not _note.text.is_empty():
+		return
+	_in_dungeon = in_dungeon
 	_hub_button.disabled = not in_dungeon
+	if in_dungeon:
+		# Disconnecting is not an escape: the server keeps the body in the
+		# world, channelling out, for the same second the escape button costs.
+		# Saying so is the difference between a considered choice and a nasty
+		# surprise -- the mechanic only reads as fair if players know about it.
+		_note.text = "The world keeps running while this is open. " \
+			+ "Disconnecting does not save you: your ship stays in the dungeon " \
+			+ "for one second and can still be killed."
+		_disconnect_button.text = "Disconnect to menu  (ship stays 1s)"
+	else:
+		_note.text = "The world keeps running while this is open."
+		_disconnect_button.text = "Disconnect to menu"

tests/unit/test_content.gd

@@ -0,0 +1,78 @@
+extends GutTest
+## Invariants every piece of content has to satisfy. These are cheap to write
+## and they are what stops a new enemy from quietly reintroducing a mechanic the
+## game has decided against.
+
+const HOSTILES := [
+	Content.ENEMY_DRIFTER,
+	Content.ENEMY_TURRET,
+	Content.ENEMY_STALKER,
+]
+
+
+## The rule: nothing in this game hurts you by touching you. Every threat is a
+## bullet you can see and dodge, so an enemy with no emitters is either inert
+## scenery or a design mistake.
+func test_every_hostile_enemy_actually_fires_something() -> void:
+	for id in HOSTILES:
+		var def := Content.enemy(id)
+		assert_gt(def.emitters.size(), 0,
+			"%s has no emitters -- it would be a harmless obstacle" % id)
+
+
+func test_the_practice_dummy_is_inert() -> void:
+	var def := Content.enemy(Content.ENEMY_DUMMY)
+	assert_eq(def.emitters.size(), 0, "the hub target must never shoot back")
+
+
+## Standing inside an enemy costs nothing by itself. Uses the dummy so the test
+## measures contact alone, with no bullets in play to confuse the result.
+func test_touching_an_enemy_deals_no_damage() -> void:
+	var world := SimWorld.new(1)
+	var p := world.add_player(1, "tester")
+	var e := world.spawn_enemy(Content.dummy(), Vector2.ZERO)
+	p.pos = e.pos
+	p.spawn_grace = 0
+	for _i in 120:
+		world.step()
+	assert_eq(p.hp, SimConfig.PLAYER_MAX_HP,
+		"contact damage is not a damage type in this game")
+
+
+## The Stalker's burst replaces its old contact damage, so it has to be a real
+## threat once it closes -- and harmless from across the arena.
+func test_the_stalker_threatens_at_point_blank_only() -> void:
+	var near := SimWorld.new(1)
+	var pn := near.add_player(1, "tester")
+	pn.pos = Vector2.ZERO
+	pn.spawn_grace = 0
+	near.spawn_enemy(Content.stalker(), Vector2(40.0, 0.0))
+	for _i in 90:
+		near.step()
+	assert_lt(pn.hp, SimConfig.PLAYER_MAX_HP, "point blank has to hurt")
+
+	var far := SimWorld.new(1)
+	var pf := far.add_player(1, "tester")
+	pf.pos = Vector2(0.0, 300.0)
+	pf.spawn_grace = 0
+	# Pinned in place so it cannot close the distance during the test.
+	var e := far.spawn_enemy(Content.stalker(), Vector2(0.0, -300.0))
+	e.def = Content.stalker()
+	e.def.speed = 0.0
+	for _i in 90:
+		far.step()
+	assert_eq(pf.hp, SimConfig.PLAYER_MAX_HP,
+		"its bullets must expire long before they cross the arena")
+
+
+func test_enemy_bullets_from_the_stalker_do_not_litter_the_arena() -> void:
+	var world := SimWorld.new(1)
+	var p := world.add_player(1, "tester")
+	p.pos = Vector2(0.0, 300.0)
+	var e := world.spawn_enemy(Content.stalker(), Vector2(0.0, -300.0))
+	e.def = Content.stalker()
+	e.def.speed = 0.0
+	for _i in 300:
+		world.step()
+	assert_lt(world.pool.live_count, 12,
+		"a short lifetime should keep spent point-blank shots from accumulating")

tests/unit/test_content.gd.uid

@@ -0,0 +1 @@
+uid://cmmr6xgf4isls

tools/smoke.sh

@@ -51,6 +51,17 @@ for n in 1 2; do
   sleep 0.4
 done
 
+# A fourth bot that leaves *politely* -- the same Net.shutdown() the in-game
+# menu's "Disconnect" button calls. The escape channel is keyed on the socket
+# closing, not on how it closed, so a clean exit must be caught exactly like the
+# SIGKILL below. If someone ever adds a "clean leave" message that bypasses the
+# channel, this is what catches it.
+"$GODOT" --headless --path . -- --bot --host 127.0.0.1 --port "$PORT" \
+  --name "leavebot" --leave-after 120 --autoquit "$CLIENT_TICKS" \
+  > "$OUT/leavebot.log" 2>&1 &
+PIDS+=($!)
+sleep 0.4
+
 # A third bot that gets SIGKILLed the moment it is inside a dungeon. This is the
 # anti-disconnect-cheese path: the server must keep its body in the world,
 # channel it out over the same one second the escape button costs, and only then
@@ -104,6 +115,9 @@ check  "bot1 returned to the lobby"  "$OUT/bot1.log"   "entered instance .*LOBBY
 check  "a hard drop is channelled, not instant" \
                                      "$OUT/server.log" "dropped in instance [0-9]+, channelling out"
 check  "the dropped body is released"  "$OUT/server.log" "released from instance [0-9]+ after drop"
+check  "a polite disconnect leaves too"  "$OUT/leavebot.log" "BOT_GRACEFUL_LEAVE"
+check  "a polite disconnect is also channelled" \
+                                     "$OUT/server.log" "'leavebot' dropped in instance [0-9]+, channelling out"
 refute "no server script errors"     "$OUT/server.log" "SCRIPT ERROR|Parse Error|USER ERROR"
 refute "no client script errors"     "$OUT/bot1.log"   "SCRIPT ERROR|Parse Error|USER ERROR"