refactor(imports): enforce guard pattern (#3382)

* refactor(imports): enforce guard pattern

* fix(tests): skip reachy2 if not installed

* Address review feedback

src/lerobot/cameras/reachy2_camera/reachy2_camera.py

@@ -33,7 +33,7 @@ import cv2  # type: ignore  # TODO: add type stubs for OpenCV
 import numpy as np  # type: ignore  # TODO: add type stubs for numpy
 
 from lerobot.utils.decorators import check_if_not_connected
-from lerobot.utils.import_utils import _reachy2_sdk_available
+from lerobot.utils.import_utils import _reachy2_sdk_available, require_package
 
 if TYPE_CHECKING or _reachy2_sdk_available:
     from reachy2_sdk.media.camera import CameraView
@@ -76,6 +76,7 @@ class Reachy2Camera(Camera):
         Args:
             config: The configuration settings for the camera.
         """
+        require_package("reachy2_sdk", extra="reachy2")
         super().__init__(config)
 
         self.config = config

src/lerobot/cameras/realsense/camera_realsense.py

@@ -19,16 +19,18 @@ Provides the RealSenseCamera class for capturing frames from Intel RealSense cam
 import logging
 import time
 from threading import Event, Lock, Thread
-from typing import Any
+from typing import TYPE_CHECKING, Any
 
 import cv2  # type: ignore  # TODO: add type stubs for OpenCV
 import numpy as np  # type: ignore  # TODO: add type stubs for numpy
 from numpy.typing import NDArray  # type: ignore  # TODO: add type stubs for numpy.typing
 
-try:
-    import pyrealsense2 as rs  # type: ignore  # TODO: add type stubs for pyrealsense2
-except Exception as e:
-    logging.info(f"Could not import realsense: {e}")
+from lerobot.utils.import_utils import _pyrealsense2_available, require_package
+
+if TYPE_CHECKING or _pyrealsense2_available:
+    import pyrealsense2 as rs
+else:
+    rs = None
 
 from lerobot.utils.decorators import check_if_already_connected, check_if_not_connected
 from lerobot.utils.errors import DeviceNotConnectedError
@@ -112,7 +114,7 @@ class RealSenseCamera(Camera):
         Args:
             config: The configuration settings for the camera.
         """
-
+        require_package("pyrealsense2", extra="intelrealsense")
         super().__init__(config)
 
         self.config = config

src/lerobot/cameras/zmq/camera_zmq.py

@@ -28,12 +28,19 @@ import json
 import logging
 import time
 from threading import Event, Lock, Thread
-from typing import Any
+from typing import TYPE_CHECKING, Any
 
 import cv2
 import numpy as np
 from numpy.typing import NDArray
 
+from lerobot.utils.import_utils import _zmq_available, require_package
+
+if TYPE_CHECKING or _zmq_available:
+    import zmq
+else:
+    zmq = None
+
 from lerobot.utils.decorators import check_if_already_connected, check_if_not_connected
 from lerobot.utils.errors import DeviceNotConnectedError
 
@@ -74,8 +81,8 @@ class ZMQCamera(Camera):
     """
 
     def __init__(self, config: ZMQCameraConfig):
+        require_package("pyzmq", extra="pyzmq-dep", import_name="zmq")
         super().__init__(config)
-        import zmq
 
         self.config = config
         self.server_address = config.server_address
@@ -117,8 +124,6 @@ class ZMQCamera(Camera):
         logger.info(f"Connecting to {self}...")
 
         try:
-            import zmq
-
             self.context = zmq.Context()
             self.socket = self.context.socket(zmq.SUB)
             self.socket.setsockopt_string(zmq.SUBSCRIBE, "")
@@ -180,11 +185,8 @@ class ZMQCamera(Camera):
 
         try:
             message = self.socket.recv_string()
-        except Exception as e:
-            # zmq is lazy-imported in connect(), so check by name to avoid a top-level import
-            if type(e).__name__ == "Again":
-                raise TimeoutError(f"{self} timeout after {self.timeout_ms}ms") from e
-            raise
+        except zmq.Again as e:
+            raise TimeoutError(f"{self} timeout after {self.timeout_ms}ms") from e
 
         # Decode JSON message
         data = json.loads(message)

src/lerobot/common/control_utils.py

@@ -28,6 +28,12 @@ import numpy as np
 import torch
 
 from lerobot.policies import PreTrainedPolicy, prepare_observation_for_inference
+from lerobot.utils.import_utils import _deepdiff_available, require_package
+
+if TYPE_CHECKING or _deepdiff_available:
+    from deepdiff import DeepDiff
+else:
+    DeepDiff = None
 
 if TYPE_CHECKING:
     from lerobot.datasets import LeRobotDataset
@@ -217,10 +223,7 @@ def sanity_check_dataset_robot_compatibility(
     Raises:
         ValueError: If any of the checked metadata fields do not match.
     """
-    from lerobot.utils.import_utils import require_package
-
-    require_package("deepdiff", extra="hardware")
-    from deepdiff import DeepDiff
+    require_package("deepdiff", extra="deepdiff-dep")
 
     from lerobot.utils.constants import DEFAULT_FEATURES
 

src/lerobot/model/kinematics.py

@@ -12,8 +12,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
 import numpy as np
 
+from lerobot.utils.import_utils import _placo_available, require_package
+
+if TYPE_CHECKING or _placo_available:
+    import placo  # type: ignore[import-not-found]
+else:
+    placo = None
+
 
 class RobotKinematics:
     """Robot kinematics using placo library for forward and inverse kinematics."""
@@ -32,13 +43,7 @@ class RobotKinematics:
             target_frame_name (str): Name of the end-effector frame in the URDF
             joint_names (list[str] | None): List of joint names to use for the kinematics solver
         """
-        try:
-            import placo  # type: ignore[import-not-found] # C++ library with Python bindings, no type stubs available. TODO: Create stub file or request upstream typing support.
-        except ImportError as e:
-            raise ImportError(
-                "placo is required for RobotKinematics. "
-                "Please install the optional dependencies of `kinematics` in the package."
-            ) from e
+        require_package("placo", extra="placo-dep")
 
         self.robot = placo.RobotWrapper(urdf_path)
         self.solver = placo.KinematicsSolver(self.robot)

src/lerobot/motors/damiao/damiao.py

@@ -24,7 +24,7 @@ from functools import cached_property
 from typing import TYPE_CHECKING, Any, TypedDict
 
 from lerobot.utils.decorators import check_if_already_connected, check_if_not_connected
-from lerobot.utils.import_utils import _can_available
+from lerobot.utils.import_utils import _can_available, require_package
 
 if TYPE_CHECKING or _can_available:
     import can
@@ -111,6 +111,7 @@ class DamiaoMotorsBus(MotorsBusBase):
             bitrate: Nominal bitrate in bps (default: 1000000 = 1 Mbps)
             data_bitrate: Data bitrate for CAN FD in bps (default: 5000000 = 5 Mbps), ignored if use_can_fd is False
         """
+        require_package("python-can", extra="damiao", import_name="can")
         super().__init__(port, motors, calibration)
         self.port = port
         self.can_interface = can_interface

src/lerobot/motors/motors_bus.py

@@ -356,8 +356,8 @@ class SerialMotorsBus(MotorsBusBase):
         motors: dict[str, Motor],
         calibration: dict[str, MotorCalibration] | None = None,
     ):
-        require_package("pyserial", extra="hardware", import_name="serial")
-        require_package("deepdiff", extra="hardware")
+        require_package("pyserial", extra="pyserial-dep", import_name="serial")
+        require_package("deepdiff", extra="deepdiff-dep")
         super().__init__(port, motors, calibration)
 
         self.port_handler: PortHandler

src/lerobot/motors/robstride/robstride.py

@@ -23,12 +23,12 @@ from types import SimpleNamespace
 from typing import TYPE_CHECKING, Any, TypedDict
 
 from lerobot.utils.decorators import check_if_already_connected, check_if_not_connected
-from lerobot.utils.import_utils import _can_available
+from lerobot.utils.import_utils import _can_available, require_package
 
 if TYPE_CHECKING or _can_available:
     import can
 else:
-    can = SimpleNamespace(Message=object, interface=None)
+    can = SimpleNamespace(Message=object, interface=None, BusABC=object)
 import numpy as np
 
 from lerobot.utils.errors import DeviceNotConnectedError
@@ -106,6 +106,7 @@ class RobstrideMotorsBus(MotorsBusBase):
             bitrate: Nominal bitrate in bps (default: 1000000 = 1 Mbps)
             data_bitrate: Data bitrate for CAN FD in bps (default: 5000000 = 5 Mbps), ignored if use_can_fd is False
         """
+        require_package("python-can", extra="robstride", import_name="can")
         super().__init__(port, motors, calibration)
         self.port = port
         self.can_interface = can_interface

src/lerobot/optim/schedulers.py

@@ -18,14 +18,21 @@ import logging
 import math
 from dataclasses import asdict, dataclass
 from pathlib import Path
+from typing import TYPE_CHECKING
 
 import draccus
 from torch.optim import Optimizer
 from torch.optim.lr_scheduler import LambdaLR, LRScheduler
 
 from lerobot.utils.constants import SCHEDULER_STATE
+from lerobot.utils.import_utils import _diffusers_available, require_package
 from lerobot.utils.io_utils import deserialize_json_into_object, write_json
 
+if TYPE_CHECKING or _diffusers_available:
+    from diffusers.optimization import get_scheduler
+else:
+    get_scheduler = None
+
 
 @dataclass
 class LRSchedulerConfig(draccus.ChoiceRegistry, abc.ABC):
@@ -47,10 +54,7 @@ class DiffuserSchedulerConfig(LRSchedulerConfig):
     num_warmup_steps: int | None = None
 
     def build(self, optimizer: Optimizer, num_training_steps: int) -> LambdaLR:
-        from lerobot.utils.import_utils import require_package
-
         require_package("diffusers", extra="diffusion")
-        from diffusers.optimization import get_scheduler
 
         kwargs = {**asdict(self), "num_training_steps": num_training_steps, "optimizer": optimizer}
         return get_scheduler(**kwargs)

src/lerobot/policies/diffusion/modeling_diffusion.py

@@ -23,6 +23,7 @@ TODO(alexander-soare):
 import math
 from collections import deque
 from collections.abc import Callable
+from typing import TYPE_CHECKING
 
 import einops
 import numpy as np
@@ -32,6 +33,14 @@ import torchvision
 from torch import Tensor, nn
 
 from lerobot.utils.constants import ACTION, OBS_ENV_STATE, OBS_IMAGES, OBS_STATE
+from lerobot.utils.import_utils import _diffusers_available, require_package
+
+if TYPE_CHECKING or _diffusers_available:
+    from diffusers.schedulers.scheduling_ddim import DDIMScheduler
+    from diffusers.schedulers.scheduling_ddpm import DDPMScheduler
+else:
+    DDIMScheduler = None
+    DDPMScheduler = None
 
 from ..pretrained import PreTrainedPolicy
 from ..utils import (
@@ -64,6 +73,7 @@ class DiffusionPolicy(PreTrainedPolicy):
             dataset_stats: Dataset statistics to be used for normalization. If not passed here, it is expected
                 that they will be passed with a call to `load_state_dict` before the policy is used.
         """
+        require_package("diffusers", extra="diffusion")
         super().__init__(config)
         config.validate_features()
         self.config = config
@@ -155,11 +165,7 @@ def _make_noise_scheduler(name: str, **kwargs: dict):
     Factory for noise scheduler instances of the requested type. All kwargs are passed
     to the scheduler.
     """
-    from lerobot.utils.import_utils import require_package
-
     require_package("diffusers", extra="diffusion")
-    from diffusers.schedulers.scheduling_ddim import DDIMScheduler
-    from diffusers.schedulers.scheduling_ddpm import DDPMScheduler
 
     if name == "DDPM":
         return DDPMScheduler(**kwargs)

src/lerobot/policies/groot/modeling_groot.py

@@ -43,6 +43,7 @@ from torch import Tensor
 
 from lerobot.configs import FeatureType, PolicyFeature
 from lerobot.utils.constants import ACTION, OBS_IMAGES
+from lerobot.utils.import_utils import require_package
 
 from ..pretrained import PreTrainedPolicy
 from .configuration_groot import GrootConfig
@@ -59,6 +60,7 @@ class GrootPolicy(PreTrainedPolicy):
 
     def __init__(self, config: GrootConfig, **kwargs):
         """Initialize Groot policy wrapper."""
+        require_package("transformers", extra="groot")
         super().__init__(config)
         config.validate_features()
         self.config = config

src/lerobot/policies/multi_task_dit/modeling_multi_task_dit.py

@@ -36,7 +36,7 @@ import torch.nn.functional as F  # noqa: N812
 import torchvision
 from torch import Tensor
 
-from lerobot.utils.import_utils import _transformers_available
+from lerobot.utils.import_utils import _diffusers_available, _transformers_available, require_package
 
 from .configuration_multi_task_dit import MultiTaskDiTConfig
 
@@ -46,6 +46,13 @@ if TYPE_CHECKING or _transformers_available:
 else:
     CLIPTextModel = None
     CLIPVisionModel = None
+
+if TYPE_CHECKING or _diffusers_available:
+    from diffusers.schedulers.scheduling_ddim import DDIMScheduler
+    from diffusers.schedulers.scheduling_ddpm import DDPMScheduler
+else:
+    DDIMScheduler = None
+    DDPMScheduler = None
 from lerobot.utils.constants import (
     ACTION,
     OBS_IMAGES,
@@ -65,6 +72,8 @@ class MultiTaskDiTPolicy(PreTrainedPolicy):
     name = "multi_task_dit"
 
     def __init__(self, config: MultiTaskDiTConfig, **kwargs):
+        require_package("transformers", extra="multi_task_dit")
+        require_package("diffusers", extra="multi_task_dit")
         super().__init__(config)
         config.validate_features()
         self.config = config
@@ -643,12 +652,6 @@ class DiffusionObjective(nn.Module):
             "prediction_type": config.prediction_type,
         }
 
-        from lerobot.utils.import_utils import require_package
-
-        require_package("diffusers", extra="multi_task_dit")
-        from diffusers.schedulers.scheduling_ddim import DDIMScheduler
-        from diffusers.schedulers.scheduling_ddpm import DDPMScheduler
-
         if config.noise_scheduler_type == "DDPM":
             self.noise_scheduler: DDPMScheduler | DDIMScheduler = DDPMScheduler(**scheduler_kwargs)
         elif config.noise_scheduler_type == "DDIM":

src/lerobot/policies/pi0/modeling_pi0.py

@@ -26,7 +26,7 @@ import torch
 import torch.nn.functional as F  # noqa: N812
 from torch import Tensor, nn
 
-from lerobot.utils.import_utils import _transformers_available
+from lerobot.utils.import_utils import _transformers_available, require_package
 
 # Conditional import for type checking and lazy loading
 if TYPE_CHECKING or _transformers_available:
@@ -947,6 +947,7 @@ class PI0Policy(PreTrainedPolicy):
         Args:
             config: Policy configuration class instance.
         """
+        require_package("transformers", extra="pi")
         super().__init__(config)
         config.validate_features()
         self.config = config

src/lerobot/policies/pi05/modeling_pi05.py

@@ -26,7 +26,7 @@ import torch
 import torch.nn.functional as F  # noqa: N812
 from torch import Tensor, nn
 
-from lerobot.utils.import_utils import _transformers_available
+from lerobot.utils.import_utils import _transformers_available, require_package
 
 # Conditional import for type checking and lazy loading
 if TYPE_CHECKING or _transformers_available:
@@ -918,6 +918,7 @@ class PI05Policy(PreTrainedPolicy):
         Args:
             config: Policy configuration class instance.
         """
+        require_package("transformers", extra="pi")
         super().__init__(config)
         config.validate_features()
         self.config = config

src/lerobot/policies/pi0_fast/modeling_pi0_fast.py

@@ -26,7 +26,7 @@ import torch
 import torch.nn.functional as F  # noqa: N812
 from torch import Tensor, nn
 
-from lerobot.utils.import_utils import _scipy_available, _transformers_available
+from lerobot.utils.import_utils import _scipy_available, _transformers_available, require_package
 
 # Conditional import for type checking and lazy loading
 if TYPE_CHECKING or _scipy_available:
@@ -35,7 +35,7 @@ else:
     idct = None
 
 if TYPE_CHECKING or _transformers_available:
-    from transformers import AutoTokenizer
+    from transformers import AutoProcessor, AutoTokenizer
     from transformers.models.auto import CONFIG_MAPPING
 
     from ..pi_gemma import (
@@ -44,6 +44,7 @@ if TYPE_CHECKING or _transformers_available:
     )
 else:
     CONFIG_MAPPING = None
+    AutoProcessor = None
     AutoTokenizer = None
     PiGemmaModel = None
     PaliGemmaForConditionalGenerationWithPiGemma = None
@@ -826,14 +827,14 @@ class PI0FastPolicy(PreTrainedPolicy):
         Args:
             config: Policy configuration class instance.
         """
+        require_package("transformers", extra="pi")
+        require_package("scipy", extra="pi")
         super().__init__(config)
         config.validate_features()
         self.config = config
 
         # Load tokenizers first
         try:
-            from transformers import AutoProcessor, AutoTokenizer
-
             # Load FAST tokenizer
             self.action_tokenizer = AutoProcessor.from_pretrained(
                 config.action_tokenizer_name, trust_remote_code=True

src/lerobot/policies/smolvla/modeling_smolvla.py

@@ -62,6 +62,7 @@ from torch import Tensor, nn
 
 from lerobot.utils.constants import ACTION, OBS_LANGUAGE_ATTENTION_MASK, OBS_LANGUAGE_TOKENS, OBS_STATE
 from lerobot.utils.device_utils import get_safe_dtype
+from lerobot.utils.import_utils import require_package
 
 from ..pretrained import PreTrainedPolicy
 from ..rtc.modeling_rtc import RTCProcessor
@@ -239,6 +240,7 @@ class SmolVLAPolicy(PreTrainedPolicy):
                     the configuration class is used.
         """
 
+        require_package("transformers", extra="smolvla")
         super().__init__(config)
         config.validate_features()
         self.config = config

src/lerobot/robots/reachy2/robot_reachy2.py

@@ -20,7 +20,7 @@ from typing import TYPE_CHECKING, Any
 
 from lerobot.cameras import make_cameras_from_configs
 from lerobot.types import RobotAction, RobotObservation
-from lerobot.utils.import_utils import _reachy2_sdk_available
+from lerobot.utils.import_utils import _reachy2_sdk_available, require_package
 
 from ..robot import Robot
 from ..utils import ensure_safe_goal_position
@@ -81,6 +81,7 @@ class Reachy2Robot(Robot):
     name = "reachy2"
 
     def __init__(self, config: Reachy2RobotConfig):
+        require_package("reachy2_sdk", extra="reachy2")
         super().__init__(config)
 
         self.config = config

src/lerobot/robots/unitree_g1/unitree_g1.py

@@ -27,7 +27,7 @@ import numpy as np
 
 from lerobot.cameras import make_cameras_from_configs
 from lerobot.types import RobotAction, RobotObservation
-from lerobot.utils.import_utils import _unitree_sdk_available
+from lerobot.utils.import_utils import _unitree_sdk_available, require_package
 
 from ..robot import Robot
 from .config_unitree_g1 import UnitreeG1Config
@@ -111,6 +111,7 @@ class UnitreeG1(Robot):
     name = "unitree_g1"
 
     def __init__(self, config: UnitreeG1Config):
+        require_package("unitree-sdk2py", extra="unitree_g1", import_name="unitree_sdk2py")
         super().__init__(config)
 
         logger.info("Initialize UnitreeG1...")

src/lerobot/teleoperators/gamepad/gamepad_utils.py

@@ -15,9 +15,22 @@
 # limitations under the License.
 
 import logging
+from typing import TYPE_CHECKING
+
+from lerobot.utils.import_utils import _hidapi_available, _pygame_available, require_package
 
 from ..utils import TeleopEvents
 
+if TYPE_CHECKING or _pygame_available:
+    import pygame
+else:
+    pygame = None  # type: ignore[assignment]
+
+if TYPE_CHECKING or _hidapi_available:
+    import hid
+else:
+    hid = None  # type: ignore[assignment]
+
 
 class InputController:
     """Base class for input controllers that generate motion deltas."""
@@ -199,6 +212,7 @@ class GamepadController(InputController):
     """Generate motion deltas from gamepad input."""
 
     def __init__(self, x_step_size=1.0, y_step_size=1.0, z_step_size=1.0, deadzone=0.1):
+        require_package("pygame", extra="gamepad")
         super().__init__(x_step_size, y_step_size, z_step_size)
         self.deadzone = deadzone
         self.joystick = None
@@ -206,8 +220,6 @@ class GamepadController(InputController):
 
     def start(self):
         """Initialize pygame and the gamepad."""
-        import pygame
-
         pygame.init()
         pygame.joystick.init()
 
@@ -230,8 +242,6 @@ class GamepadController(InputController):
 
     def stop(self):
         """Clean up pygame resources."""
-        import pygame
-
         if pygame.joystick.get_init():
             if self.joystick:
                 self.joystick.quit()
@@ -240,8 +250,6 @@ class GamepadController(InputController):
 
     def update(self):
         """Process pygame events to get fresh gamepad readings."""
-        import pygame
-
         for event in pygame.event.get():
             if event.type == pygame.JOYBUTTONDOWN:
                 if event.button == 3:
@@ -280,8 +288,6 @@ class GamepadController(InputController):
 
     def get_deltas(self):
         """Get the current movement deltas from gamepad state."""
-        import pygame
-
         try:
             # Read joystick axes
             # Left stick X and Y (typically axes 0 and 1)
@@ -326,6 +332,7 @@ class GamepadControllerHID(InputController):
             z_scale: Scaling factor for Z-axis movement
             deadzone: Joystick deadzone to prevent drift
         """
+        require_package("hidapi", extra="gamepad", import_name="hid")
         super().__init__(x_step_size, y_step_size, z_step_size)
         self.deadzone = deadzone
         self.device = None
@@ -342,8 +349,6 @@ class GamepadControllerHID(InputController):
 
     def find_device(self):
         """Look for the gamepad device by vendor and product ID."""
-        import hid
-
         devices = hid.enumerate()
         for device in devices:
             device_name = device["product_string"]
@@ -357,8 +362,6 @@ class GamepadControllerHID(InputController):
 
     def start(self):
         """Connect to the gamepad using HIDAPI."""
-        import hid
-
         self.device_info = self.find_device()
         if not self.device_info:
             self.running = False

src/lerobot/teleoperators/homunculus/homunculus_arm.py

@@ -45,7 +45,7 @@ class HomunculusArm(Teleoperator):
     name = "homunculus_arm"
 
     def __init__(self, config: HomunculusArmConfig):
-        require_package("pyserial", extra="hardware", import_name="serial")
+        require_package("pyserial", extra="pyserial-dep", import_name="serial")
         super().__init__(config)
         self.config = config
         self.serial = serial.Serial(config.port, config.baud_rate, timeout=1)

src/lerobot/teleoperators/homunculus/homunculus_glove.py

@@ -71,7 +71,7 @@ class HomunculusGlove(Teleoperator):
     name = "homunculus_glove"
 
     def __init__(self, config: HomunculusGloveConfig):
-        require_package("pyserial", extra="hardware", import_name="serial")
+        require_package("pyserial", extra="pyserial-dep", import_name="serial")
         super().__init__(config)
         self.config = config
         self.serial = serial.Serial(config.port, config.baud_rate, timeout=1)

src/lerobot/teleoperators/keyboard/teleop_keyboard.py

@@ -23,7 +23,7 @@ from typing import Any
 
 from lerobot.types import RobotAction
 from lerobot.utils.decorators import check_if_already_connected, check_if_not_connected
-from lerobot.utils.import_utils import _pynput_available
+from lerobot.utils.import_utils import _pynput_available, require_package
 
 from ..teleoperator import Teleoperator
 from ..utils import TeleopEvents
@@ -56,6 +56,7 @@ class KeyboardTeleop(Teleoperator):
     name = "keyboard"
 
     def __init__(self, config: KeyboardTeleopConfig):
+        require_package("pynput", extra="pynput-dep")
         super().__init__(config)
         self.config = config
         self.robot_type = config.type

src/lerobot/teleoperators/phone/teleop_phone.py

@@ -21,14 +21,24 @@
 import logging
 import threading
 import time
+from typing import TYPE_CHECKING
 
-import hebi
 import numpy as np
-from teleop import Teleop
 
 from lerobot.utils.decorators import check_if_already_connected, check_if_not_connected
+from lerobot.utils.import_utils import _hebi_available, _teleop_available, require_package
 from lerobot.utils.rotation import Rotation
 
+if TYPE_CHECKING or _hebi_available:
+    import hebi
+else:
+    hebi = None
+
+if TYPE_CHECKING or _teleop_available:
+    from teleop import Teleop
+else:
+    Teleop = None
+
 from ..teleoperator import Teleoperator
 from .config_phone import PhoneConfig, PhoneOS
 
@@ -74,6 +84,8 @@ class IOSPhone(BasePhone, Teleoperator):
     name = "ios_phone"
 
     def __init__(self, config: PhoneConfig):
+        require_package("hebi-py", extra="phone", import_name="hebi")
+        require_package("teleop", extra="phone")
         super().__init__(config)
         self.config = config
         self._group = None
@@ -213,6 +225,8 @@ class AndroidPhone(BasePhone, Teleoperator):
     name = "android_phone"
 
     def __init__(self, config: PhoneConfig):
+        require_package("hebi-py", extra="phone", import_name="hebi")
+        require_package("teleop", extra="phone")
         super().__init__(config)
         self.config = config
         self._teleop = None

src/lerobot/teleoperators/reachy2_teleoperator/reachy2_teleoperator.py

@@ -19,7 +19,7 @@ import logging
 import time
 from typing import TYPE_CHECKING
 
-from lerobot.utils.import_utils import _reachy2_sdk_available
+from lerobot.utils.import_utils import _reachy2_sdk_available, require_package
 
 if TYPE_CHECKING or _reachy2_sdk_available:
     from reachy2_sdk import ReachySDK
@@ -84,6 +84,7 @@ class Reachy2Teleoperator(Teleoperator):
     name = "reachy2_specific"
 
     def __init__(self, config: Reachy2TeleoperatorConfig):
+        require_package("reachy2_sdk", extra="reachy2")
         super().__init__(config)
 
         self.config = config

src/lerobot/teleoperators/unitree_g1/exo_calib.py

@@ -34,7 +34,7 @@ from typing import TYPE_CHECKING
 
 import numpy as np
 
-from lerobot.utils.import_utils import _serial_available
+from lerobot.utils.import_utils import _serial_available, require_package
 
 if TYPE_CHECKING or _serial_available:
     import serial
@@ -156,6 +156,7 @@ def run_exo_calibration(
     """
     Run interactive calibration for an exoskeleton arm.
     """
+    require_package("pyserial", extra="unitree_g1", import_name="serial")
     try:
         import cv2
         import matplotlib.pyplot as plt

src/lerobot/teleoperators/unitree_g1/exo_serial.py

@@ -76,7 +76,7 @@ class ExoskeletonArm:
     calibration: ExoskeletonCalibration | None = None
 
     def __post_init__(self):
-        require_package("pyserial", extra="hardware", import_name="serial")
+        require_package("pyserial", extra="unitree_g1", import_name="serial")
         if self.calibration_fpath.is_file():
             self._load_calibration()
 

src/lerobot/utils/import_utils.py

@@ -115,6 +115,12 @@ _feetech_sdk_available = is_package_available("feetech-servo-sdk", import_name="
 _reachy2_sdk_available = is_package_available("reachy2_sdk")
 _can_available = is_package_available("python-can", "can")
 _unitree_sdk_available = is_package_available("unitree-sdk2py", "unitree_sdk2py")
+_pyrealsense2_available = is_package_available("pyrealsense2")
+_zmq_available = is_package_available("pyzmq", import_name="zmq")
+_hebi_available = is_package_available("hebi-py", import_name="hebi")
+_teleop_available = is_package_available("teleop")
+_placo_available = is_package_available("placo")
+_hidapi_available = is_package_available("hidapi", import_name="hid")
 
 # Data / serialization
 _pandas_available = is_package_available("pandas")