Failed to view file changes. Unhandled error

Description

I get “Error Loading Notebook Diff: Unhandled error” when I look at file changes.

Reproduce

1. Make changes to a file
2. Go to Git sidebar
3. Stage commit
4. Add message
5. Press Commit
6. Go to History Tab
7. Click on changes
8. Error display on main view

Expected behavior

I expect that see the change history.

Context

After installing anaconda, I configured the proxy settings for anaconda and executed the following command.

> conda install jupyterlab-git
> nbdime config-git --enable --global

• Python package version:

> conda list jupyterlab-git
jupyterlab-git    0.30.1    pyhd8ed1ab_0    conda-forge

• Extension version:

>jupyter labextension list
JupyterLab v3.0.14
C:\ProgramData\Anaconda3\share\jupyter\labextensions
        nbdime-jupyterlab v2.1.0 enabled ok
        @jupyter-widgets/jupyterlab-manager v3.0.0 enabled ok (python, jupyterlab_widgets)
        @jupyterlab/git v0.30.1 enabled ok (python, jupyterlab-git)

Other labextensions (built into JupyterLab)
   app dir: C:\ProgramData\Anaconda3\share\jupyter\lab

>jupyter server extension list
Config dir: C:\Users\localadmin\.jupyter

Config dir: C:\ProgramData\Anaconda3\etc\jupyter
    jupyter_server_mathjax enabled
    - Validating jupyter_server_mathjax...
      jupyter_server_mathjax  ok
    jupyterlab enabled
    - Validating jupyterlab...
      jupyterlab 3.0.14 ok
    jupyterlab_git enabled
    - Validating jupyterlab_git...
      jupyterlab_git 0.30.1 ok
    nbclassic enabled
    - Validating nbclassic...
      nbclassic  ok
    nbdime enabled
    - Validating nbdime...
      nbdime 3.1.0 ok

Config dir: C:\ProgramData\jupyter

• Git version:

> git --version
git version 2.31.1.windows.1

• Operating System and its version:

Windows Server 2016
Anaconda3-2021.05-Windows-x86_64

Command Line Output

[I 2021-06-08 10:47:45.637 LabApp] Build is up to date
[W 10:47:52.372 NotebookApp.jupyterlab_git] Fail to execute ['git', 'diff', '--numstat', '4b825dc642cb6eb9a060e54bf8d69288fbee4904', '289e12f459513f1bc28ae6a07463ec95db95cfc7', '--', '00_public/01_Settings/Master/Setting Creator.ipynb']
    Traceback (most recent call last):
      File "C:\ProgramData\Anaconda3\lib\site-packages\jupyterlab_git\git.py", line 142, in execute
        code, output, error = await current_loop.run_in_executor(
      File "C:\ProgramData\Anaconda3\lib\concurrent\futures\thread.py", line 57, in run
        result = self.fn(*self.args, **self.kwargs)
      File "C:\ProgramData\Anaconda3\lib\site-packages\jupyterlab_git\git.py", line 108, in call_subprocess
        process = subprocess.Popen(
      File "C:\ProgramData\Anaconda3\lib\subprocess.py", line 858, in __init__
        self._execute_child(args, executable, preexec_fn, close_fds,
      File "C:\ProgramData\Anaconda3\lib\subprocess.py", line 1311, in _execute_child
        hp, ht, pid, tid = _winapi.CreateProcess(executable, args,
    NotADirectoryError: [WinError 267] ディレクトリ名が無効です。
[E 10:47:52.372 NotebookApp] Uncaught exception POST /git/content?1623116872354 (***.***.***.***)
    HTTPServerRequest(protocol='http', host='servername:9999', method='POST', uri='/git/content?1623116872354', version='HTTP/1.1', remote_ip='***.***.***.***')
    Traceback (most recent call last):
      File "C:\ProgramData\Anaconda3\lib\site-packages\tornado\web.py", line 1704, in _execute
        result = await result
      File "C:\ProgramData\Anaconda3\lib\site-packages\jupyterlab_git\handlers.py", line 668, in post
        response = await self.git.get_content_at_reference(
      File "C:\ProgramData\Anaconda3\lib\site-packages\jupyterlab_git\git.py", line 1249, in get_content_at_reference
        is_binary = await self._is_binary(filename, reference["git"], top_repo_path)
      File "C:\ProgramData\Anaconda3\lib\site-packages\jupyterlab_git\git.py", line 1302, in _is_binary
        code, output, error = await execute(command, cwd=top_repo_path)
      File "C:\ProgramData\Anaconda3\lib\site-packages\jupyterlab_git\git.py", line 159, in execute
        return code, output, error
    UnboundLocalError: local variable 'code' referenced before assignment
[W 10:47:52.372 NotebookApp] Unhandled error

Web Browser Output

Error Loading Notebook Diff: Unhandled error

Jupyter Config

c.NotebookApp.ip = '0.0.0.0'
c.NotebookApp.notebook_dir = 'c:/00_workarea'
c.NotebookApp.open_browser = False
c.NotebookApp.quit_button = False
c.NotebookApp.port = 9999
c.NotebookApp.token = 'xxxxx'

[rs57770917]

Thank you very much. After changing the settings, it shows up correctly.

[fcollonval]

You may be right. Could you try using ‘c:\00_workarea’ to use Windows path separator.

Comment: since JupyterLab 3, you need to use c.ServerApp instead of c.NotebookApp - the latter will not be supported in the future.