How to Fix Fatal Python Error: PyThreadState_Get: No Current Thread

1. What Causes PyThreadState_Get: no current thread Error
2. Use sudo to Solve PyThreadState_Get: no current thread Error
3. Use otool to Solve PyThreadState_Get: no current thread Error

On our local machine, we could have different Python version installations which can only do what’s limited or new to that version at any given time.

We can get issues if we write code within a version context with all its dependencies and that code runs in another Python version context.

One of these issues is the PyThreadState_Get: no current thread, and in this article, we will discuss what causes it and how to resolve it on your local Mac/Linux PC.

What Causes PyThreadState_Get: no current thread Error

Multiple Python installations have different modules and dependencies attached to them, but when we run Python code, the wrong Python binding might end up linking against the system provided by our PC. This scenario often happens when using macOS.

Therefore, we must ensure that the right Python (with our modules) runs our code and links the right modules to our system Python.

Use sudo to Solve PyThreadState_Get: no current thread Error

If you have multiple Python installations, different libraries may use Python, and to solve the PyThreadState_Get: no current thread error message, we can change the active Python to the Python installation that as the default libraries that you were calling previously within your code.

To change the active Python installation, we can use the below sudo command.

sudo port select --list python

The output of the command:

Available versions for python:
    none
    python26-apple
    python27
    python27-apple (active)
    python34

From the above output, the active Python installation is python27-apple, and to switch the Python installation that holds the dependencies and modules, you need python34.

To change to python34, we can use the sudo command below.

sudo port select python python34

After we execute the above command, we can check if it worked by using the --list command.

sudo port select --list python

The command output should now show that python34 is active.

Available versions for python:
    none
    python26-apple
    python27
    python27-apple
    python34 (active)

Use otool to Solve PyThreadState_Get: no current thread Error

Often, the main cause of the PyThreadState_Get: no current thread error message when running your code is often the use of a library (import statement) with another Python installation that doesn’t recognize it. We can solve the problem using the otool and install_name_tool utilities.

To solve it, we will need to use the Python library (for example, Leap Motion) with the alternate Python installation and must update the library’s loader path to reference the Python installation we want.

First, use the otool command to check the current loader paths.

otool -L LeapPython.so

The output of the command:

LeapPython.so:
    @loader_path/LeapPython.so (compatibility version 0.0.0, current version 0.0.0)
    /Library/Frameworks/Python.framework/Versions/3.4/Python (compatibility version 3.4.0, current version 3.4.0)
    @loader_path/libLeap.dylib (compatibility version 0.7.0, current version 2.0.1)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 169.3.0)

So we need to change and update the current Python location/reference, /Library/Frameworks/Python.framework/Versions/3.4/Python, to our desired Python installation. To do that, we need to use the install_name_tool command.

Once we execute the command, we have referenced the new Python installation location to the library we want to use.

install_name_tool -change /Library/Frameworks/Python.framework/Versions/3.4/Python \
/usr/local/Cellar/python/3.8.8/Frameworks/Python.framework/Versions/3.8/lib/libpython3.8.dylib \
LeapPython.so

Now, we can run our Python code without facing the PyThreadState_Get: no current thread error message.