In the BlockedUnlockPickupEnv, interacting with an empty box deletes the box, and creates an unsolvable situation.

minigrid/core/roomgrid.py

@@ -76,6 +76,7 @@ def __init__(
         num_cols: int = 3,
         max_steps: int = 100,
         agent_view_size: int = 7,
+        fix_empty_box_bug: bool = False,
         **kwargs,
     ):
         assert room_size > 0
@@ -85,6 +86,7 @@ def __init__(
         self.room_size = room_size
         self.num_rows = num_rows
         self.num_cols = num_cols
+        self.fix_empty_box_bug = fix_empty_box_bug
 
         height = (room_size - 1) * num_rows + 1
         width = (room_size - 1) * num_cols + 1
@@ -219,7 +221,7 @@ def add_object(
         elif kind == "ball":
             obj = Ball(color)
         elif kind == "box":
-            obj = Box(color)
+            obj = Box(color, fix_empty_box_bug=self.fix_empty_box_bug)
         else:
             raise ValueError(
                 f"{kind} object kind is not available in this environment."

minigrid/core/world_object.py

@@ -270,9 +270,15 @@ def render(self, img):
 
 
 class Box(WorldObj):
-    def __init__(self, color, contains: WorldObj | None = None):
+    def __init__(
+        self,
+        color,
+        contains: WorldObj | None = None,
+        fix_empty_box_bug: bool = False,
+    ):
         super().__init__("box", color)
         self.contains = contains
+        self.fix_empty_box_bug = fix_empty_box_bug
 
     def can_pickup(self):
         return True
@@ -288,6 +294,9 @@ def render(self, img):
         fill_coords(img, point_in_rect(0.16, 0.84, 0.47, 0.53), c)
 
     def toggle(self, env, pos):
+        if self.fix_empty_box_bug and self.contains is None:
+            return False
+
         # Replace the box by its contents
         env.grid.set(pos[0], pos[1], self.contains)
         return True

minigrid/envs/babyai/other.py

@@ -76,7 +76,11 @@ class ActionObjDoor(RoomGridLevel):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make a
+    pickup instruction on an empty box permanently unreachable.
+
     - `BabyAI-ActionObjDoor-v0`
+    - `BabyAI-ActionObjDoor-v1`
 
     """
 
@@ -154,9 +158,15 @@ class FindObjS5(RoomGridLevel):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make the
+    pickup goal permanently unreachable when the randomly-chosen object was a box.
+
     - `BabyAI-FindObjS5-v0`
+    - `BabyAI-FindObjS5-v1`
     - `BabyAI-FindObjS6-v0`
+    - `BabyAI-FindObjS6-v1`
     - `BabyAI-FindObjS7-v0`
+    - `BabyAI-FindObjS7-v1`
 
     """
 
@@ -383,8 +393,13 @@ class MoveTwoAcross(RoomGridLevel):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make the
+    move object permanently uncarryable when it was drawn as a box.
+
     - `BabyAI-MoveTwoAcrossS5N2-v0`
+    - `BabyAI-MoveTwoAcrossS5N2-v1`
     - `BabyAI-MoveTwoAcrossS8N9-v0`
+    - `BabyAI-MoveTwoAcrossS8N9-v1`
 
     """
 

minigrid/envs/babyai/pickup.py

@@ -59,7 +59,11 @@ class Pickup(RoomGridLevel):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make the
+    pickup goal permanently unreachable when it was drawn as a box.
+
     - `BabyAI-Pickup-v0`
+    - `BabyAI-Pickup-v1`
 
     """
 
@@ -122,7 +126,11 @@ class UnblockPickup(RoomGridLevel):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make the
+    pickup goal permanently unreachable when it was drawn as a box.
+
     - `BabyAI-UnblockPickup-v0`
+    - `BabyAI-UnblockPickup-v1`
 
     """
 
@@ -192,7 +200,11 @@ class PickupLoc(LevelGen):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make the
+    pickup goal permanently unreachable when it was drawn as a box.
+
     - `BabyAI-PickupLoc-v0`
+    - `BabyAI-PickupLoc-v1`
 
     """
 
@@ -264,8 +276,13 @@ class PickupDist(RoomGridLevel):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make the
+    pickup goal permanently unreachable when it was drawn as a box.
+
     - `BabyAI-PickupDist-v0`
+    - `BabyAI-PickupDist-v1`
     - `BabyAI-PickupDistDebug-v0`
+    - `BabyAI-PickupDistDebug-v1`
 
     """
 
@@ -340,7 +357,11 @@ class PickupAbove(RoomGridLevel):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make the
+    pickup goal permanently unreachable when it was drawn as a box.
+
     - `BabyAI-PickupAbove-v0`
+    - `BabyAI-PickupAbove-v1`
 
     """
 

minigrid/envs/babyai/putnext.py

@@ -59,9 +59,15 @@ class PutNextLocal(RoomGridLevel):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make the
+    move object permanently uncarryable when it was drawn as a box.
+
     - `BabyAI-PutNextLocal-v0`
+    - `BabyAI-PutNextLocal-v1`
     - `BabyAI-PutNextLocalS5N3-v0`
-    - `BabyAI-PutNextLocalS6N4-v0``
+    - `BabyAI-PutNextLocalS5N3-v1`
+    - `BabyAI-PutNextLocalS6N4-v0`
+    - `BabyAI-PutNextLocalS6N4-v1`
 
     """
 
@@ -131,11 +137,21 @@ class PutNext(RoomGridLevel):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make the
+    move object permanently uncarryable when it was drawn as a box. The
+    `*Carrying` configurations start with the move object already held, so they
+    are not affected and have no v1 counterpart.
+
     - `BabyAI-PutNextS4N1-v0`
+    - `BabyAI-PutNextS4N1-v1`
     - `BabyAI-PutNextS5N2-v0`
+    - `BabyAI-PutNextS5N2-v1`
     - `BabyAI-PutNextS5N1-v0`
+    - `BabyAI-PutNextS5N1-v1`
     - `BabyAI-PutNextS6N3-v0`
+    - `BabyAI-PutNextS6N3-v1`
     - `BabyAI-PutNextS7N4-v0`
+    - `BabyAI-PutNextS7N4-v1`
     - `BabyAI-PutNextS5N2Carrying-v0`
     - `BabyAI-PutNextS6N3Carrying-v0`
     - `BabyAI-PutNextS7N4Carrying-v0`

minigrid/envs/babyai/synth.py

@@ -75,8 +75,13 @@ class Synth(LevelGen):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make a
+    pickup or put-next goal permanently unreachable when it involved a box.
+
     - `BabyAI-Synth-v0`
+    - `BabyAI-Synth-v1`
     - `BabyAI-SynthS5R2-v0`
+    - `BabyAI-SynthS5R2-v1`
 
     """
 
@@ -163,7 +168,11 @@ class SynthLoc(LevelGen):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make a
+    pickup or put-next goal permanently unreachable when it involved a box.
+
     - `BabyAI-SynthLoc-v0`
+    - `BabyAI-SynthLoc-v1`
     """
 
     def __init__(self, **kwargs):
@@ -268,7 +277,11 @@ class SynthSeq(LevelGen):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make a
+    pickup or put-next goal permanently unreachable when it involved a box.
+
     - `BabyAI-SynthSeq-v0`
+    - `BabyAI-SynthSeq-v1`
 
     """
 
@@ -370,7 +383,11 @@ class MiniBossLevel(LevelGen):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make a
+    pickup or put-next goal permanently unreachable when it involved a box.
+
     - `BabyAI-MiniBossLevel-v0`
+    - `BabyAI-MiniBossLevel-v1`
 
     """
 
@@ -473,7 +490,11 @@ class BossLevel(LevelGen):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make a
+    pickup or put-next goal permanently unreachable when it involved a box.
+
     - `BabyAI-BossLevel-v0`
+    - `BabyAI-BossLevel-v1`
     """
 
     def __init__(self, **kwargs):
@@ -569,7 +590,11 @@ class BossLevelNoUnlock(LevelGen):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make a
+    pickup or put-next goal permanently unreachable when it involved a box.
+
     - `BabyAI-BossLevelNoUnlock-v0`
+    - `BabyAI-BossLevelNoUnlock-v1`
     """
 
     def __init__(self, **kwargs):

minigrid/envs/babyai/unlock.py

@@ -289,8 +289,13 @@ class UnlockPickup(RoomGridLevel):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make the
+    pickup goal permanently unreachable.
+
     - `BabyAI-UnlockPickup-v0`
+    - `BabyAI-UnlockPickup-v1`
     - `BabyAI-UnlockPickupDist-v0`
+    - `BabyAI-UnlockPickupDist-v1`
 
     """
 
@@ -364,7 +369,11 @@ class BlockedUnlockPickup(RoomGridLevel):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make the
+    pickup goal permanently unreachable.
+
     - `BabyAI-BlockedUnlockPickup-v0`
+    - `BabyAI-BlockedUnlockPickup-v1`
 
     """
 

minigrid/envs/blockedunlockpickup.py

@@ -59,7 +59,11 @@ class BlockedUnlockPickupEnv(RoomGrid):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make the
+    pickup goal permanently unreachable.
+
     - `MiniGrid-BlockedUnlockPickup-v0`
+    - `MiniGrid-BlockedUnlockPickup-v1`
 
     """
 

minigrid/envs/putnear.py

@@ -61,14 +61,27 @@ class PutNearEnv(MiniGridEnv):
 
     N: number of objects.
 
+    "v1" prevents toggling an empty box from deleting it, which used to make the
+    move object permanently uncarryable if it was drawn as an empty box.
+
     - `MiniGrid-PutNear-6x6-N2-v0`
     - `MiniGrid-PutNear-8x8-N3-v0`
+    - `MiniGrid-PutNear-6x6-N2-v1`
+    - `MiniGrid-PutNear-8x8-N3-v1`
 
     """
 
-    def __init__(self, size=6, numObjs=2, max_steps: int | None = None, **kwargs):
+    def __init__(
+        self,
+        size=6,
+        numObjs=2,
+        max_steps: int | None = None,
+        fix_empty_box_bug: bool = False,
+        **kwargs,
+    ):
         self.size = size
         self.numObjs = numObjs
+        self.fix_empty_box_bug = fix_empty_box_bug
         self.obj_types = ["key", "ball", "box"]
         mission_space = MissionSpace(
             mission_func=self._gen_mission,
@@ -136,7 +149,7 @@ def near_obj(env, p1):
             elif objType == "ball":
                 obj = Ball(objColor)
             elif objType == "box":
-                obj = Box(objColor)
+                obj = Box(objColor, fix_empty_box_bug=self.fix_empty_box_bug)
             else:
                 raise ValueError(
                     "{} object type given. Object type can only be of values key, ball and box.".format(

minigrid/envs/unlockpickup.py

@@ -52,7 +52,11 @@ class UnlockPickupEnv(RoomGrid):
 
     ## Registered Configurations
 
+    "v1" prevents toggling an empty box from deleting it, which used to make the
+    pickup goal permanently unreachable.
+
     - `MiniGrid-UnlockPickup-v0`
+    - `MiniGrid-UnlockPickup-v1`
 
     """