Fix some dungeon generation errors:

TR fails if the Big Chest entrance is locked behind another dungeon
Hyrule Castle fails if the only available entrance is Sanctuary

DoorShuffle.py

@@ -13,7 +13,7 @@ from Dungeons import dungeon_regions, region_starts, split_region_starts, flexib
 from Dungeons import drop_entrances, dungeon_bigs, dungeon_keys
 from Items import ItemFactory
 from RoomData import DoorKind, PairedDoor
-from DungeonGenerator import ExplorationState, convert_regions, generate_dungeon
+from DungeonGenerator import ExplorationState, convert_regions, generate_dungeon, validate_tr
 from DungeonGenerator import create_dungeon_builders, split_dungeon_builder, simple_dungeon_builder
 from KeyDoorShuffle import analyze_dungeon, validate_vanilla_key_logic, build_key_layout, validate_key_layout
 
@@ -339,7 +339,7 @@ def main_dungeon_generation(dungeon_builders, recombinant_builders, connections_
         origin_list = list(builder.entrance_list)
         find_enabled_origins(builder.sectors, enabled_entrances, origin_list, entrances_map, name)
         origin_list_sans_drops = remove_drop_origins(origin_list)
-        if len(origin_list_sans_drops) <= 0:
+        if len(origin_list_sans_drops) <= 0 or name == "Turtle Rock" and not validate_tr(name, builder.sectors, origin_list_sans_drops, world, player):
             if last_key == builder.name:
                 raise Exception('Infinte loop detected %s' % builder.name)
             sector_queue.append(builder)

DungeonGenerator.py

@@ -31,6 +31,25 @@ class GraphPiece:
         self.possible_bk_locations = set()
 
 
+# Turtle Rock shouldn't be generated until the Big Chest entrance is reachable
+def validate_tr(name, available_sectors, entrance_region_names, world, player):
+    entrance_regions = convert_regions(entrance_region_names, world, player)
+    proposed_map = {}
+    doors_to_connect = {}
+    all_regions = set()
+    bk_needed = False
+    bk_special = False
+    for sector in available_sectors:
+        for door in sector.outstanding_doors:
+            doors_to_connect[door.name] = door
+        all_regions.update(sector.regions)
+        bk_needed = bk_needed or determine_if_bk_needed(sector, False, world, player)
+        bk_special = bk_special or check_for_special(sector)
+    dungeon, hangers, hooks = gen_dungeon_info(name, available_sectors, entrance_regions, proposed_map,
+                                               doors_to_connect, bk_needed, bk_special, world, player)
+    return check_valid(dungeon, hangers, hooks, proposed_map, doors_to_connect, all_regions, bk_needed, False)
+
+
 def generate_dungeon(name, available_sectors, entrance_region_names, split_dungeon, world, player):
     logger = logging.getLogger('')
     entrance_regions = convert_regions(entrance_region_names, world, player)

Dungeons.py

@@ -350,7 +350,7 @@ flexible_starts = {
 }
 
 drop_entrances = [
-    'Sewers Rat Path', 'Skull Pinball', 'Skull Left Drop'  # Pot circle, Back drop have unique access
+    'Sewers Rat Path', 'Skull Pinball', 'Skull Left Drop', 'Sanctuary'  # Pot circle, Back drop have unique access
 ]
 
 dungeon_keys = {