[vscode] Running example FileSystemProvider plugin has different behavior

[Glamhoth]

Bug Description:

When trying to use example FileSystemProvider plugin the (expected) behavior on Code[1] differs from the behavior on Theia[2].

[1] Running plugin command Setup workspace with or without opened workspace creates new and empty directory with name that was passed to vscode.workspace.updateWorkspaceFolders in extension.ts.

[2] Running plugin command Setup workspace without opened workspace throws an error Failed to update workspace folders: Error: There is not active workspace. If any folder was already opened in the workspace, the same plugin command opens new directory, but instead of named, empty one it's system's root.

Steps to Reproduce:

1. Clone microsoft/vscode-extension-samples
2. Add fsprovider-sample plugin to Theia
3. Run Theia
4. Execute Setup workspace command from the command paletter

Additional Information

• Operating System:
  Ubuntu 18.04 if running on Docker image
  Arch Linux, kernel 5.7.7 if running on host
• Theia Version:
  Tried both release 1.3.0 and compiling akosyakov/integrate-vscode-api-7269 branch.

[akosyakov]

Thought it is related to fs APIs, but it is related to workspace APIs. I think it is known bug that we don't respect workspace names yet.

[Glamhoth]

How does workspace support for custom scheme/filesystem provider look like? In the example plugin a memfs scheme is registered, but even if I try to manually edit the workspace file it's not recognized.

[akosyakov]

I don't think it is related to fs providers, it is about:

vscode.workspace.updateWorkspaceFolders(0, 0, { uri: vscode.Uri.parse('memfs:/'), name: "MemFS - Sample" });

We ignore currently MemFS - Sample all together. I've started working on it once, but did not have time to finish: #7222

[Glamhoth]

But this plugin registers provider
vscode.workspace.registerFileSystemProvider('memfs', memFs, { isCaseSensitive: true });
so I thought that if I would create workspace in Theia and then manually edit it to point at folder in memfs schema like this:

{
    "folders": [
        {
            "path": "memfs:///folder"
        }
    ]
}

it would correctly show those files that are initialized by memfs.init command. Instead path changes to this: /home/glamhoth/.theia/memfs:///folder, which seems like workspace is always treating uris as they would be in file schema. It's not related to names probably, but maybe am I missing/misunderstaning something, or schema stuff is not fully implemented in Theia's workspace?

[akosyakov]

I see, it looks like another bug in our WorkspaceService.

[shomeier]

I also just tried to implement an own FileSystemProvider and got the same issue.

It looks like the problem is in WorkspaceService.transformToAbsolute:

    if (path.startsWith('file:///')) {
        folders.push(path);
    } else {
        folders.push(workspaceFile.resource.withScheme('file').parent.resolve(path).toString());
    }

If I remove the lines 1,3,4 and 5 and simply push the path to the folders array my FileSystemProvider is hit properly with its scheme.