Jupyterlab-git doesn't like Windows network drives

[scdevries]

Description

I'm working in a network drive that has a Windows drive letter (H:) mapped to it. Whenever I try to do a DIFF I get one of two different errors:

Failed to fetch diff with error:Unhandled error

or

Failed to fetch diff with error:Unexpected token H in JSON at position 0

I believe the former happens for plain text files and the other for .ipynb files.

This does not happen when I'm using the same repository on a normal disk.

Reproduce

1. Go to a repository on a network drive, wait for the repository to be recognized (can take up to a minute or so, it's somehow very slow)
2. Click on the history tab, and select one point in this history
3. Click on a file name to view file changes
4. See the above mentioned errors

Expected behavior

On a standard Windows file path I get a normal, nice notebook diff. On a network drive I don't get that.

Context

In the developer tools of the browser I can see the following happening when performing above mentioned DIFF (watch the file path):

Invoke-WebRequest -Uri "http://localhost:8888/nbdime/api/gitdiff?1589304998232" `
-Method "POST" `
-Headers @{
"User-Agent"="Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.122 Safari/537.36"
  "X-XSRFToken"="2|9b634a47|etcetcetc"
  "Authorization"="token eteeteetc"
  "Accept"="*/*"
  "Origin"="http://localhost:8888"
  "Sec-Fetch-Site"="same-origin"
  "Sec-Fetch-Mode"="cors"
  "Sec-Fetch-Dest"="empty"
  "Referer"="http://localhost:8888/lab"
  "Accept-Encoding"="gzip, deflate, br"
  "Accept-Language"="en-GB,en-US;q=0.9,en;q=0.8"
  "Cookie"="_xsrf=2|9b634a47|etcetcetc; username-localhost-8889=`"2|1:0|10:1589272611|23:username-localhost-8889|etc`""
} `
-ContentType "application/json" `
-Body "{`"file_path`":`"../../../XXXXX.CORP/FS/RM/RMVM/1. Val/IF9/12 IF9 Framework/2020/2. Code library/3. Model Output - Accuracy.ipynb`",`"ref_local`":{`"git`":`"c31766db6aab37cee15c36c5d77c54a3748187eb`"},`"ref_remote`":{`"git`":`"db34480c53bf45a38845f14643e873beeb76ddd1`"}}"

The response is also useful information. It seems to show that the file path is somewhat mangled (again):

HTTP 422: Unprocessable Entity (Invalid notebook: H:\XXXXX.CORP\FS\RM\RMVM\1. Val\IF9\12 IF9 Framework\2020\2. Code library\3. Model Output - Accuracy.ipynb)

Note that the correct windows path should be either:
"H:\RMVM\1. Val\IF9\12 IF9 Framework\2020\2. Code library \3. Model Output - Accuracy.ipynb"
or
\XXXXX.corp\FS\RM\RMVM\1\1. Val\IF9\12 IF9 Framework\2020\2. Code library \3. Model Output - Accuracy.ipynb

This is a cross post from jupyter/nbdime#524 (comment)

• Python package version:
  jupyterlab-git 0.20.0 py_1 conda-forge
• Extension version:
  JupyterLab v2.1.2
  Known labextensions:
  app dir: C:\Users\VriesSC\Miniconda3\envs\Toolbox\share\jupyter\lab
  @jupyter-widgets/jupyterlab-manager v2.0.0 enabled ok
  @jupyterlab/celltags v2.1.2 enabled ok
  @jupyterlab/git v0.20.0 enabled ok
  @jupyterlab/toc v3.0.0 enabled ok
  @lckr/jupyterlab_variableinspector v0.5.0 enabled ok
  nbdime-jupyterlab v2.0.0 enabled ok
• Git version:
  git version 2.26.2.windows.1
• Operating System and its version:
  Microsoft Windows 10 Enterprise
  Version 10.0.17763 Build 17763

Command Line Output

Paste the output from your command line running `jupyter lab` here, use `--debug` if possible.

Browser Output

Paste the output from your browser Javascript console here.

[ktaletsk]

I confirm this bug exist. There is an inconsistency in execution path calculation here:

jupyterlab-git/jupyterlab_git/handlers.py

Line 668 in b8ba586

top_repo_path = os.path.join(cm.root_dir, url2path(data["top_repo_path"]))

I experimented with cloning the same repo in Windows on external drive and on the main drive, as well as cloning this repo in Ubuntu (WSL). Here's what the path variables were:

	Windows (C://)	Windows (network drive, H://)	Ubuntu (/home/)
cm.root_dir	C:\Users\konst\Code\test_git_push	H:\\notebooks	/home/ktaletsk/git/test_git_push
url2path(data["top_repo_path"])	empty	..\..\SYNOLOGYNAS\home\notebooks\test_git_push	empty
top_repo_path	C:\Users\konst\Code\test_git_push	H:\\notebooks\..\..\SYNOLOGYNAS\home\notebooks\test_git_push	/home/ktaletsk/git/test_git_push

We should see where this inconsistency is coming from, upstream to that call

[ktaletsk]

Digging more, I see that there the problematic relative path in url2path(data["top_repo_path"]) (..\..\SYNOLOGYNAS\home\notebooks\test_git_push) for network drives stems from calculating incorrect relative path in model.getRelativeFilePath:

jupyterlab-git/src/model.ts

Lines 602 to 610 in b8ba586

	getRelativeFilePath(path?: string): string | null {
	if (this.pathRepository === null || this._serverRoot === void 0) {
	return null;
	}
	return PathExt.join(
	PathExt.relative(this._serverRoot, this.pathRepository),
	path || ''
	);
	}

	Windows (C://)	Windows (network drive, H://)	Ubuntu (/home/)
this._serverRoot	C:/Users/konst/Code/test_git_push	H:/notebooks	/home/ktaletsk/git/test_git_push
this.pathRepository	C:/Users/konst/Code/test_git_push	//SYNOLOGYNAS/home/notebooks/test_git_push	/home/ktaletsk/git/test_git_push
return value	empty	H:\\notebooks\..\..\SYNOLOGYNAS\home\notebooks\test_git_push	empty

The correct output in case of external drive should be test_git_push, however the function cannot calculate it because it is given two paths in different formats.

Let's look where both variables are coming from:

1. _serverRoot comes from gitExtension constructor called in activate function:

   jupyterlab-git/src/index.ts

   Lines 116 to 121 in b8ba586

   	gitExtension = new GitExtension(
   	serverSettings.serverRoot,
   	docmanager,
   	app.docRegistry,
   	settings
   	);

   In turn, that comes from API call to /git/settings, where it is obtained from Contents Manager:

   jupyterlab-git/jupyterlab_git/handlers.py

   Lines 718 to 719 in b8ba586

   	root_dir = getattr(self.contents_manager, "root_dir", None)
   	server_root = None if root_dir is None else Path(root_dir).as_posix()

2. pathRepository is also set in activate function and comes from filebrowser

   jupyterlab-git/src/index.ts

   Line 125 in b8ba586

   gitExtension.pathRepository = filebrowser.model.path;

   which is IFileBrowserFactory.defaultBrowser.model.path

So, overall the issue seem to be coming from inconsistent path formatting for external drives coming from contents manager (H:/notebooks) and filebrowser (//SYNOLOGYNAS/home/notebooks/test_git_push). We can either try to fix the issue upstream or try to work around it.

[mesvam]

Can confirm this as well. I get "Unable to get the lock on the directory" error during diffs. If I copy the git repo to a local drive, it gets rid of the errors