Studio Web 查看器无法使用: 轮子中缺少 studio.web.headless_ui

Introduction Hi! I'm from AWS. I use MuJoCo for headless physics simulation and offscreen rendering distributed across many workers, and I have been trying Studio's Python bindings to add an in-viewer UI. ### My setup Reproduced on both: - MuJoCo 3.13.0 (PyPI wheel), Python 3.11.5, arm64, macOS 26.6.2 - MuJoCo 3.13.0 (PyPI wheel), Python 3.14.4, x86_64, Ubuntu 26.04 API: Python. ### What's happening? What did you expect? web_viewer.py imports headless_ui from mujoco.experimental.studio.web, but that module is not present in the wheel. Selecting the web or webgl graphics mode therefore fails. viewer_protocol.GFX_MODES advertises both modes: Python ('classic', 'classic_headless', 'opengl', 'opengl_headless', 'opengl_software', 'vulkan', 'vulkan_software', 'web', 'webgl') so they are selectable but cannot work. I expected either a working web viewer, or for the unavailable modes not to be offered. The failure also arrives awkwardly. It happens on the viewer thread, so launch_passive returns a handle and is_running() reports True at first, turning False only later: launch_passive returned: ViewerHandle is_running: True Exception in thread Thread-1 (target): Traceback (most recent call last): ... File ".../studio/launch_web.py", line 39, in run_web_viewer from mujoco.experimental.studio import web_viewer File ".../studio/web_viewer.py", line 51, in from mujoco.experimental.studio.web import headless_ui ImportError: cannot import name 'headless_ui' from 'mujoco.experimental.studio.web' (unknown location) is_running after 5s: False Process exit status is 0, so a script that does not poll is_running() will not notice at all. ### Cause The shipped web package contains only web_server.py: $ ls site-packages/mujoco/experimental/studio/web/ pycache web_server.py There is also no __init__.py, which is why the message says "unknown location". ### Why it matters beyond the web viewer On macOS this is currently the only Studio backend that avoids the main-thread window problem (filed separately), because rendering happens in the browser. With it unavailable, there is no working way to run Studio from Python on macOS without a workaround. ### Suggested fix Ship headless_ui, and an __init__.py for the web package. Alternatively, remove web and webgl from GFX_MODES until they ship, so the failure surfaces at configuration time rather than as a traceback on a background thread. ### Steps for reproduction 1. pip install mujoco==3.13.0 2. Confirm the module is absent: Python -c "from mujoco.experimental.studio.web import headless_ui" Or go through the documented path: save minimal.xml and repro.py below into the same directory and run Python repro.py ### Minimal model for reproduction The model is not material to this bug, since the failure occurs during viewer startup before the model is used. Included for completeness, loadable as-is ...