Cats on bridges, no more infinite familiar call loops

Server/src/main/content/global/skill/construction/HouseZone.java

@@ -115,6 +115,14 @@ public final class HouseZone extends MapZone {
                     return true;
                 }
             }
+            
+            // Take the player's familiar along before the teardown pulse below wipes every NPC
+            // still left inside the house - a wiped familiar is gone until relog (GL #2313). The
+            // call either materializes it at the destination or parks it invisibly at the owner's
+            // side until there is room for it.
+            if (!logout && p.getFamiliarManager().hasFamiliar()) {
+                p.getFamiliarManager().getFamiliar().call();
+            }
 
             remove_items(p);
             // The below tears down the house if the owner was the one who left

Server/src/main/content/global/skill/summoning/familiar/Familiar.java

@@ -391,10 +391,17 @@ public abstract class Familiar extends NPC implements Plugin<Object> {
 		
 		return false;
 	}
-
+	
 	@Override
 	public void onRegionInactivity() {
 		call();
+		// NPC.tick() short-circuits into this method while the region is inactive, so Entity.tick()
+		// never runs to consume a teleport that call() just set; apply it manually here or the
+		// familiar re-calls forever without ever moving (GL #2313).
+		if (getProperties().getTeleportLocation() != null && owner.isActive()) {
+			getWalkingQueue().update();
+			getUpdateMasks().prepare(this);
+		}
 	}
 
 	@Override
@@ -699,10 +706,20 @@ public abstract class Familiar extends NPC implements Plugin<Object> {
 			//owner.getPacketDispatch().sendMessage("Your familiar is too big to fit here. Try calling it again when you are standing");
 			//owner.getPacketDispatch().sendMessage("somewhere with more space.");
 			//spamTimer = 50;
+			// No room to materialize, so wait invisibly at the owner's side (like init() does when
+			// there is no room at summon time). Waiting in place instead means being left behind:
+			// once the abandoned region unloads, the familiar either gets wiped with it
+			// (DynamicRegion teardown) or gets stuck endlessly re-calling from an inactive region
+			// that no longer ticks it normally (GL #2313).
+			setInvisible(true);
+			stayWithOwner();
 			return false;
 		}
 		setInvisible(owner.getZoneMonitor().isRestricted(ZoneRestriction.FOLLOWERS) && !owner.getLocks().isLocked("enable_summoning"));
-		if (isInvisible()) return true;
+		if (isInvisible()) {
+			stayWithOwner();
+			return true;
+		}
 		getProperties().setTeleportLocation(destination);
 		if (!(this instanceof Pet)) {
 			if (firstCall) {
@@ -723,13 +740,33 @@ public abstract class Familiar extends NPC implements Plugin<Object> {
 		} else {
 			face(owner);
 		}
-		if (!isRenderable() && owner.isActive()) {
+		// A familiar pulled in from another region must move immediately rather than on its next
+		// tick: NPCs tick before players, so when this call runs from the owner's movement (e.g.
+		// leaving a POH), the familiar's tick for this cycle has already passed - and a region
+		// teardown pulse (POH exit portal, building-mode rebuild) runs at the start of the next
+		// cycle, wiping any NPC still inside before it can consume a pending teleport (GL #2313).
+		boolean leftInAnotherRegion = getLocation().getRegionId() != owner.getLocation().getRegionId();
+		if ((!isRenderable() || leftInAnotherRegion) && owner.isActive()) {
 			// log(this.getClass(), Log.ERR,  "Familiar in inactive region!");
 			getWalkingQueue().update();
 			getUpdateMasks().prepare(this);
 		}
 		return true;
 	}
+	
+	/**
+	 * Moves a familiar that cannot materialize to its owner's location, so it is never left
+	 * behind in a region that may unload. The teleport is applied immediately because this can
+	 * run from an inactive region, where Entity.tick() (the normal consumer) no longer runs.
+	 */
+	private void stayWithOwner() {
+		if (!owner.isActive() || getLocation().equals(owner.getLocation())) {
+			return;
+		}
+		getProperties().setTeleportLocation(owner.getLocation());
+		getWalkingQueue().update();
+		getUpdateMasks().prepare(this);
+	}
 
 	/**
 	 * Gets the spawning location of the familiar.

Server/src/main/core/game/world/map/RegionManager.kt

@@ -332,10 +332,14 @@ object RegionManager {
                 }
             }
             val l = owner.location.transform(stepX, stepY, 0)
-            // Check if ALL target tiles are unclipped
+            // Check if the NPC can stand on ALL target tiles. This must not use isClipped(),
+            // which rejects any tile that has a wall along ANY of its sides: every tile of a
+            // railed bridge deck has one (e.g. the whole Lumbridge bridge), which made familiars
+            // and pets unable to materialize anywhere on it (GL #1471). Materializing is the
+            // same question as teleporting, so ask the teleport predicate.
             for (x in 0 until node.size()) {
                 for (y in 0 until node.size()) {
-                    if (isClipped(l.transform(x, y, 0))) {
+                    if (!isTeleportPermitted(l.transform(x, y, 0))) {
                         continue@outer
                     }
                 }