Mujoco-py is incompatible with cython 3 (Cannot assign type 'void (const char *) except * nogil' to 'void (*)(const char *) noexcept nogil)

[pseudo-rnd-thoughts]

Describe the bug
Cannot assign type 'void (const char *) except * nogil' to 'void (*)(const char *) noexcept nogil'

To Reproduce
Install cpython 3.0.0, import mujoco-py

Expected behavior
mujoco-py compiles

Error Messages
From gymnasium's CI

tests/wrappers/test_passive_env_checker.py:9: in <module>
    from tests.envs.test_envs import PASSIVE_CHECK_IGNORE_WARNING
<frozen importlib._bootstrap>:991: in _find_and_load
    ???
<frozen importlib._bootstrap>:975: in _find_and_load_unlocked
    ???
<frozen importlib._bootstrap>:671: in _load_unlocked
    ???
../lib/python3.8/site-packages/_pytest/assertion/rewrite.py:168: in exec_module
    exec(co, module.__dict__)
tests/envs/test_envs.py:10: in <module>
    from tests.envs.utils import (
tests/envs/utils.py:34: in <module>
    all_testing_initialised_envs: List[Optional[gym.Env]] = [
tests/envs/utils.py:35: in <listcomp>
    try_make_env(env_spec) for env_spec in gym.envs.registry.values()
tests/envs/utils.py:22: in try_make_env
    return env_spec.make(disable_env_checker=True).unwrapped
gymnasium/envs/registration.py:130: in make
    return make(self, **kwargs)
gymnasium/envs/registration.py:756: in make
    env_creator = load_env_creator(env_spec.entry_point)
gymnasium/envs/registration.py:545: in load_env_creator
    mod = importlib.import_module(mod_name)
../lib/python3.8/importlib/__init__.py:127: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
gymnasium/envs/mujoco/__init__.py:1: in <module>
    from gymnasium.envs.mujoco.mujoco_env import MujocoEnv, MuJocoPyEnv  # isort:skip
gymnasium/envs/mujoco/mujoco_env.py:13: in <module>
    import mujoco_py
/mujoco-py/mujoco_py/__init__.py:2: in <module>
    from mujoco_py.builder import cymj, ignore_mujoco_warnings, functions, MujocoException
/mujoco-py/mujoco_py/builder.py:504: in <module>
    cymj = load_cython_ext(mujoco_path)
/mujoco-py/mujoco_py/builder.py:110: in load_cython_ext
    cext_so_path = builder.build()
/mujoco-py/mujoco_py/builder.py:226: in build
    built_so_file_path = self._build_impl()
/mujoco-py/mujoco_py/builder.py:278: in _build_impl
    so_file_path = super()._build_impl()
/mujoco-py/mujoco_py/builder.py:239: in _build_impl
    dist.ext_modules = cythonize([self.extension])
../lib/python3.8/site-packages/Cython/Build/Dependencies.py:1134: in cythonize
    cythonize_one(*args)
../lib/python3.8/site-packages/Cython/Build/Dependencies.py:1301: in cythonize_one
    raise CompileError(None, pyx_file)
E   Cython.Compiler.Errors.CompileError: /mujoco-py/mujoco_py/cymj.pyx
------------------------------- Captured stdout --------------------------------
Compiling /mujoco-py/mujoco_py/cymj.pyx because it changed.
[1/1] Cythonizing /mujoco-py/mujoco_py/cymj.pyx
------------------------------- Captured stderr --------------------------------

Error compiling Cython file:
------------------------------------------------------------
...
    See c_warning_callback, which is the C wrapper to the user defined function
    '''
    global py_warning_callback
    global mju_user_warning
    py_warning_callback = warn
    mju_user_warning = c_warning_callback
                       ^
------------------------------------------------------------

/mujoco-py/mujoco_py/cymj.pyx:92:23: Cannot assign type 'void (const char *) except * nogil' to 'void (*)(const char *) noexcept nogil'

Error compiling Cython file:
------------------------------------------------------------
...
    See c_warning_callback, which is the C wrapper to the user defined function
    '''
    global py_error_callback
    global mju_user_error
    py_error_callback = err_callback
    mju_user_error = c_error_callback
                     ^
------------------------------------------------------------

/mujoco-py/mujoco_py/cymj.pyx:127:21: Cannot assign type 'void (const char *) except * nogil' to 'void (*)(const char *) noexcept nogil'

[JayanthRR]

Facing the same issue.

[ChengDaHaI]

Same issue on my side

[pseudo-rnd-thoughts]

I solved it with pip install "cython<3"

[fyqqyf]

Same issue on my side

[AdilZouitine]

Same

[ezhang7423]

TYSM for figuring this out, wasted 3 hours today

[fyqqyf]

TYSM for figuring this out, wasted 3 hours today

4 hours and 5 times recreate virtual environments 😇

[alafumee]

already have Cython==0.29.36 but the same error exists when pip install mujoco_py==2.0.2.7

[qodfathr]

already have Cython==0.29.36 but the same error exists when pip install mujoco_py==2.0.2.7

Same

[ezhang7423]

I am using mujoco-py==1.50.1.68

[qodfathr]

I cannot tell if this is directly related to cython 3 or not. I have 0.29.36 installed (and I've tried many versions from 0.27.2 on up) and the same error is occurring even on mujoco_py==2.0.2.13. I tried to determine if a patch to the underlying c++ compiler was at fault, but that does not seem to be the case.

[pseudo-rnd-thoughts]

I cannot tell if this is directly related to cython 3 or not. I have 0.29.36 installed (and I've tried many versions from 0.27.2 on up) and the same error is occurring even on mujoco_py==2.0.2.13. I tried to determine if a patch to the underlying c++ compiler was at fault, but that does not seem to be the case.

I would be surprised as our CI should be failing if this was true but it is not failing with cython < 3 also if you are getting the same issue with nogil in the error then this is a cython >= 3 thing

[qodfathr]

I would be surprised as our CI should be failing if this was true but it is not failing with cython < 3 also if you are getting the same issue with nogil in the error then this is a cython >= 3 thing

I now have it working with mujoco_py==2.0.2.5, but no later 2.0.2.x releases. I see that 2.0.2.5 is probably the last "official" 2.0.2 release, but PyPi is misleading.

[reginald-mclean]

I was able to use

pip install 'cython<3'

to compile mujoco-py 2.1.2.14 on Ubuntu 22.04, Python 3.8

[Zebin-Li]

same, cython<3 not works for me

[zuhu2195]

I was facing the similar issue in numpy-1.23.3 build with cython 3.0.0, using pip3 install "cython<3" worked for me.

[HasarinduPerera]

I solved it with pip install "cython<3"

Does not work for me, I am trying to install safety-gym.

mujoco200
mujoco-py 2.1.2.14
Ubuntu 20.04
Python 3.6

Anyone found any other ways to resolve?

TIA

[zuhu2195]

What is your current Cython version?

[HasarinduPerera]

What is your current Cython version?

Cython 0.29.36

[zuhu2195]

can you try updating your python to a higher version like 3.8.

[HasarinduPerera]

can you try updating your python to a higher version like 3.8.

No progress.

[HasarinduPerera]

I would be surprised as our CI should be failing if this was true but it is not failing with cython < 3 also if you are getting the same issue with nogil in the error then this is a cython >= 3 thing

I now have it working with mujoco_py==2.0.2.5, but no later 2.0.2.x releases. I see that 2.0.2.5 is probably the last "official" 2.0.2 release, but PyPi is misleading.

This Worked!

[mynkpl1998]

Surprisingly, uninstalling Cython fixed the problem for me.

Python: 3.8
gymnasium==0.29.1
mujoco==2.3.7

Mujoco version: 2.10

[harryting-yiting]

1. Add a compiler directive " compiler_directives={'legacy_implicit_noexcept': True}" to the line 239 of mujoco_py/builder.py

 def _build_impl(self):
        dist = Distribution({
            "script_name": None,
            "script_args": ["build_ext"]
        })
        dist.ext_modules = cythonize([self.extension],compiler_directives={'legacy_implicit_noexcept': True})

2. Update Cython to the latest 3.0.2 version.

pip install -U Cython

3. The reasons can be found here
   [MAINT, Cython] Implicit noexcept is deprecated in Cython 3.0 scikit-learn/scikit-learn#25609
   [BUG] enum classes cannot be used in cdef class method declarations cython/cython#5637

[zerlinwang]

I would be surprised as our CI should be failing if this was true but it is not failing with cython < 3 also if you are getting the same issue with nogil in the error then this is a cython >= 3 thing

I now have it working with mujoco_py==2.0.2.5, but no later 2.0.2.x releases. I see that 2.0.2.5 is probably the last "official" 2.0.2 release, but PyPi is misleading.

This Worked!

It works for my.

[glorgao]

I am use mujoco210 and mujoco_py==2.1.2.14
This command helps for the cymj error:

I solved it with pip install "cython<3"

Thanks!

[glorgao]

I solved it with pip install "cython<3"

Does not work for me, I am trying to install safety-gym.

mujoco200 mujoco-py 2.1.2.14 Ubuntu 20.04 Python 3.6

Anyone found any other ways to resolve?

TIA

mujoco-py 2.1.2.14 and mujoco200 are not match. Use mujoco_py 2.1.2.14 with mujoco210, or mujoco>2.0 <2.1 with mujoco200.

[iLern]

1. Add a compiler directive " compiler_directives={'legacy_implicit_noexcept': True}" to the line 239 of mujoco_py/builder.py

 def _build_impl(self):
        dist = Distribution({
            "script_name": None,
            "script_args": ["build_ext"]
        })
        dist.ext_modules = cythonize([self.extension],compiler_directives={'legacy_implicit_noexcept': True})

2. Update Cython to the latest 3.0.2 version.

pip install -U Cython

3. The reasons can be found here
   [MAINT, Cython] Implicit noexcept is deprecated in Cython 3.0 scikit-learn/scikit-learn#25609
   [BUG] enum classes cannot be used in cdef class method declarations cython/cython#5637

This works for my problem. Thanks a lot.

my env:

• Ubuntu 22.04
• python 3.8
• mujoco 2.1.0
• mujoco-py 2.1.2.14
• Cython 3.0.6

[Zsk0]

1. Add a compiler directive " compiler_directives={'legacy_implicit_noexcept': True}" to the line 239 of mujoco_py/builder.py

 def _build_impl(self):
        dist = Distribution({
            "script_name": None,
            "script_args": ["build_ext"]
        })
        dist.ext_modules = cythonize([self.extension],compiler_directives={'legacy_implicit_noexcept': True})

2. Update Cython to the latest 3.0.2 version.

pip install -U Cython

3. The reasons can be found here
   [MAINT, Cython] Implicit noexcept is deprecated in Cython 3.0 scikit-learn/scikit-learn#25609
   [BUG] enum classes cannot be used in cdef class method declarations cython/cython#5637

This works for my problem. Thanks a lot.

my env:

• Ubuntu 22.04
• python 3.8
• mujoco 2.1.0
• mujoco-py 2.1.2.14
• Cython 3.0.6

This works!
Thanks

[YupuLu]

pip install Cython==3.0.0a10 works for me.

My env:
Ubuntu 20.04
python 3.8.17
mujoco 2.1.0
mujoco-py 2.1.2.14

[ZhaoRunyi]

1. Add a compiler directive " compiler_directives={'legacy_implicit_noexcept': True}" to the line 239 of mujoco_py/builder.py

 def _build_impl(self):
        dist = Distribution({
            "script_name": None,
            "script_args": ["build_ext"]
        })
        dist.ext_modules = cythonize([self.extension],compiler_directives={'legacy_implicit_noexcept': True})

2. Update Cython to the latest 3.0.2 version.

pip install -U Cython

3. The reasons can be found here
   [MAINT, Cython] Implicit noexcept is deprecated in Cython 3.0 scikit-learn/scikit-learn#25609
   [BUG] enum classes cannot be used in cdef class method declarations cython/cython#5637

This cause me "AttributeError: module ‘mujoco_py’ has no attribute 'utils’"
after following the instructions from 4. https://blog.csdn.net/shouchen1/article/details/130002566 (it
's a Chinese blog), which is make chage to the test code provided by the official website:

import mujoco_py 
from mujoco_py import utils # this line is added
import os
mj_path = utils.discover_mujoco() # change mujoco.utils->utils
xml_path = os.path.join(mj_path, 'model', 'humanoid.xml')
model = mujoco_py.load_model_from_path(xml_path)
sim = mujoco_py.MjSim(model)

the problem solved.

[MSiba]

already have Cython==0.29.36 but the same error exists when pip install mujoco_py==2.0.2.7

Did you find a workaround for this?

[dhruvmsheth]

Here are the steps that worked for me:

pip install "cython<3"
conda install gxx_linux-64
sudo ln -sf /usr/bin/gcc /home/dhruvstra/anaconda3/envs/argus/bin/x86_64-conda-linux-gnu-cc

The /home/dhruvstra/anaconda3/envs/argus/bin/x86_64-conda-linux-gnu-cc should be your path to where conda linux gnu is installed. It might be located at usr/bin/

and the most important one was:
conda install -c conda-forge gcc=12.1.0

[gaisibo]

Here are the steps that worked for me:

pip install "cython<3"
conda install gxx_linux-64
sudo ln -sf /usr/bin/gcc /home/dhruvstra/anaconda3/envs/argus/bin/x86_64-conda-linux-gnu-cc

The /home/dhruvstra/anaconda3/envs/argus/bin/x86_64-conda-linux-gnu-cc should be your path to where conda linux gnu is installed. It might be located at usr/bin/

and the most important one was: conda install -c conda-forge gcc=12.1.0

This works for me! Thank you!

[awesomeNabi]

Here are the steps that worked for me:

pip install "cython<3"
conda install gxx_linux-64
sudo ln -sf /usr/bin/gcc /home/dhruvstra/anaconda3/envs/argus/bin/x86_64-conda-linux-gnu-cc

The /home/dhruvstra/anaconda3/envs/argus/bin/x86_64-conda-linux-gnu-cc should be your path to where conda linux gnu is installed. It might be located at usr/bin/

and the most important one was: conda install -c conda-forge gcc=12.1.0

wonderful!!!it works

[varungupta31]

None of the other approaches worked for me, I started afresh and followed this:

#803

This finally worked. If you just want to run mujoco, this is worth a shot :)

Copy-pasting the contents of the linked discussion, credit to @Josh00-Lu

## Create conda
conda create -n demo python=3.9 mesalib glew glfw -c conda-forge -y
conda activate demo

## Install mujoco dependency
USER_DIR=$USER
echo $USER_DIR
wget -c "https://mujoco.org/download/mujoco210-linux-x86_64.tar.gz"
mkdir -p /home/$USER_DIR/.mujoco
cp mujoco210-linux-x86_64.tar.gz /home/$USER_DIR/mujoco.tar.gz
rm mujoco210-linux-x86_64.tar.gz
mkdir -p /home/$USER_DIR/.mujoco
tar -zxvf /home/$USER_DIR/mujoco.tar.gz -C /home/$USER_DIR/.mujoco
echo "export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/$USER_DIR/.mujoco/mujoco210/bin" >> ~/.bashrc
echo "export MUJOCO_PY_MUJOCO_PATH=/home/$USER_DIR/.mujoco/mujoco210" >> ~/.bashrc

# activate 
source ~/.bashrc
conda activate demo

#  install 
export CC="/usr/bin/gcc"
pip install "mujoco_py>=2.0"
pip install "cython<3"

# compile mujoco using gcc
python
import mujoco_py