Objectpos over limit: Avoid crash caused by sector over limit

Reduce the object limit by mapblock size, to avoid objects being
added just inside the map generation limit but in a block and sector
that extend beyond the map generation limit.

Change notification of 'objectpos over limit' from red in-chat ERROR
to in-terminal only WARNING, since this will happen often using mob
mods near the world's edge.

src/mapblock.h

@@ -669,14 +669,18 @@ typedef std::vector<MapBlock*> MapBlockVect;
 
 inline bool objectpos_over_limit(v3f p)
 {
-	const float map_gen_limit_bs = MYMIN(MAX_MAP_GENERATION_LIMIT,
+	// MAP_BLOCKSIZE must be subtracted to avoid an object being spawned just
-		g_settings->getU16("map_generation_limit")) * BS;
+	// within the map generation limit but in a block and sector that extend
-	return (p.X < -map_gen_limit_bs
+	// beyond the map generation limit.
-		|| p.X > map_gen_limit_bs
+	// This avoids crashes caused by sector over limit in createSector().
-		|| p.Y < -map_gen_limit_bs
+	const float object_limit = (MYMIN(MAX_MAP_GENERATION_LIMIT,
-		|| p.Y > map_gen_limit_bs
+		g_settings->getU16("map_generation_limit")) - MAP_BLOCKSIZE) * BS;
-		|| p.Z < -map_gen_limit_bs
+	return (p.X < -object_limit
-		|| p.Z > map_gen_limit_bs);
+		|| p.X > object_limit
+		|| p.Y < -object_limit
+		|| p.Y > object_limit
+		|| p.Z < -object_limit
+		|| p.Z > object_limit);
 }
 
 /*

src/serverenvironment.cpp

@@ -1667,7 +1667,7 @@ u16 ServerEnvironment::addActiveObjectRaw(ServerActiveObject *object,
 
 	if (objectpos_over_limit(object->getBasePosition())) {
 		v3f p = object->getBasePosition();
-		errorstream << "ServerEnvironment::addActiveObjectRaw(): "
+		warningstream << "ServerEnvironment::addActiveObjectRaw(): "
 			<< "object position (" << p.X << "," << p.Y << "," << p.Z
 			<< ") outside maximum range" << std::endl;
 		if (object->environmentDeletes())