Files do not open from side panel if lab started from subdirectory of git

[krassowski]

Description

When working on jupyterlab repo if I start jupyterlab from packages sub-directory and try to open a modified file from the git sidebar it shows:

Uncaught (in promise) Error: No such file or directory: packages/completer/style/base.css

The path here is wrong: it starts at the git root, but it should be relative to jupyterlab root.

Context

• Python package version: 0.41.0
• Extension version: @jupyterlab/git v0.41.0 enabled OK (python, jupyterlab-git)
• Git version: 2.37.2
• Operating System and its version: Ubuntu, latest

[fcollonval]

That case is really tricky. I think the only correct behavior we should accept is denying the folder as being a git repository.

The reason is that otherwise we do not respect the security rule of not accessing files upper than the server root directory.