Kernel spec produced for Windows is invalid

[jjkavalam]

System requirements

• Windows (Mine is Windows 10, this problem must be there for any Windows version)

Steps to reproduce

• Clone the repository and run gradlew install
• After that from suitable command prompt such as the 'Anaconda prompt' run jupyter kernelspec list

Error

(base) D:\jupyter-kernels\kotlin-jupyter>jupyter kernelspec list
[ListKernelSpecs] WARNING | Error loading kernelspec 'kotlin'
Traceback (most recent call last):
  File "D:\Anaconda3\lib\site-packages\jupyter_client\kernelspec.py", line 258, in get_all_specs
    spec = self._get_kernel_spec_by_name(kname, resource_dir)
  File "D:\Anaconda3\lib\site-packages\jupyter_client\kernelspec.py", line 201, in _get_kernel_spec_by_name
    return self.kernel_spec_class.from_resource_dir(resource_dir)
  File "D:\Anaconda3\lib\site-packages\jupyter_client\kernelspec.py", line 47, in from_resource_dir
    kernel_dict = json.load(f)
  File "D:\Anaconda3\lib\json\__init__.py", line 299, in load
    parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw)
  File "D:\Anaconda3\lib\json\__init__.py", line 354, in loads
    return _default_decoder.decode(s)
  File "D:\Anaconda3\lib\json\decoder.py", line 339, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "D:\Anaconda3\lib\json\decoder.py", line 355, in raw_decode
    obj, end = self.scan_once(s, idx)
json.decoder.JSONDecodeError: Invalid \escape: line 2 column 32 (char 33)
Available kernels:
  kotlin        C:\Users\jjkav\.ipython\kernels\kotlin
  javascript    C:\Users\jjkav\AppData\Roaming\jupyter\kernels\javascript
  python3       D:\Anaconda3\share\jupyter\kernels\python3

As can be seen there is an issue with the kernel.json installed by kotlin-jupyter:

json.decoder.JSONDecodeError: Invalid \escape: line 2 column 32 (char 33)

[sciencegirl100]

Even after trying to replace \ with \\ it still fails for me.

[W 19:25:28.771 NotebookApp] Error loading kernelspec 'kotlin' Traceback (most recent call last): File "C:\Users\scien\Anaconda3\lib\site-packages\jupyter_client\kernelspec.py", line 258, in get_all_specs spec = self._get_kernel_spec_by_name(kname, resource_dir) File "C:\Users\scien\Anaconda3\lib\site-packages\jupyter_client\kernelspec.py", line 201, in _get_kernel_spec_by_name return self.kernel_spec_class.from_resource_dir(resource_dir) File "C:\Users\scien\Anaconda3\lib\site-packages\jupyter_client\kernelspec.py", line 47, in from_resource_dir kernel_dict = json.load(f) File "C:\Users\scien\Anaconda3\lib\json\__init__.py", line 296, in load parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw) File "C:\Users\scien\Anaconda3\lib\json\__init__.py", line 348, in loads return _default_decoder.decode(s) File "C:\Users\scien\Anaconda3\lib\json\decoder.py", line 337, in decode obj, end = self.raw_decode(s, idx=_w(s, 0).end()) File "C:\Users\scien\Anaconda3\lib\json\decoder.py", line 353, in raw_decode obj, end = self.scan_once(s, idx) json.decoder.JSONDecodeError: Invalid \escape: line 2 column 32 (char 33)

[altavir]

Seems to be working now on Win10. Close?

[ileasile]

Issue was fixed with this commit: f127118

Note that it's not obvious where Jupyter finds kernel spec it tries to run. For more information look into this: https://jupyter-client.readthedocs.io/en/stable/kernels.html#kernel-specs

If you're still having troubles, old kernel spec in some other path may be the reason. In my case, it was old spec in ~\AppData\Roaming\jupyter\kernels\kotlin. To fix it, you may specify the path to this spec in gradle.properties, and then re-install the kernel.

If it doesn't help, feel free to open a new issue.