Some map border related fixes

1. Check for entity addition success in spawn_item implementation
2. Check for success in item_drop callback, so that the player
doesn't lose the item if they are outside bounds and try to drop it.
3. When existing player joins game, check that their position is inside
map bounds. If not, set their position to the return value of findSpawnPos().
4. Make findSpawnPos() respect the border

2 fixes a lua crash if a player drops an item outside map bounds.
3 fixes an assertion crash if a player leaves when being outside map bounds,
and then rejoins.

1 files changed, 17 insertions, 7 deletions

diff --git a/src/server.cpp b/src/server.cpp
index 9b1b142eb..fbdaa5918 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -3263,10 +3263,6 @@ v3f Server::findSpawnPos()
 		return nodeposf * BS;
 	}
 
-	// Default position is static_spawnpoint
-	// We will return it if we don't found a good place
-	v3s16 nodepos(nodeposf.X, nodeposf.Y, nodeposf.Z);
-
 	s16 water_level = map.getWaterLevel();
 
 	bool is_good = false;
@@ -3286,7 +3282,7 @@ v3f Server::findSpawnPos()
 		if (groundheight > water_level + 6) // Don't go to high places
 			continue;
 
-		nodepos = v3s16(nodepos2d.X, groundheight, nodepos2d.Y);
+		v3s16 nodepos(nodepos2d.X, groundheight, nodepos2d.Y);
 
 		s32 air_count = 0;
 		for (s32 i = 0; i < 10; i++) {
@@ -3295,7 +3291,11 @@ v3f Server::findSpawnPos()
 			content_t c = map.getNodeNoEx(nodepos).getContent();
 			if (c == CONTENT_AIR || c == CONTENT_IGNORE) {
 				air_count++;
-				if (air_count >= 2){
+				if (air_count >= 2) {
+					nodeposf = intToFloat(nodepos, BS);
+					// Don't spawn the player outside map boundaries
+					if (objectpos_over_limit(nodeposf))
+						continue;
 					is_good = true;
 					break;
 				}
@@ -3304,7 +3304,7 @@ v3f Server::findSpawnPos()
 		}
 	}
 
-	return intToFloat(nodepos, BS);
+	return nodeposf;
 }
 
 PlayerSAO* Server::emergePlayer(const char *name, u16 peer_id, u16 proto_version)
@@ -3353,6 +3353,16 @@ PlayerSAO* Server::emergePlayer(const char *name, u16 peer_id, u16 proto_version
 
 		// Add player to environment
 		m_env->addPlayer(player);
+	} else {
+		// If the player exists, ensure that they respawn inside legal bounds
+		// This fixes an assert crash when the player can't be added
+		// to the environment
+		if (objectpos_over_limit(player->getPosition())) {
+			actionstream << "Respawn position for player \""
+				<< name << "\" outside limits, resetting" << std::endl;
+			v3f pos = findSpawnPos();
+			player->setPosition(pos);
+		}
 	}
 
 	// Create a new player active object