[ls] implement multiple workspace folders in MonacoWorkspace

[JanKoehnlein]

Fixes #6108

Signed-off-by: Jan Koehnlein jan.koehnlein@typefox.io

What it does

This PR adds support of multiple workspace root folders to Monaco workspace.
Language servers will be notified with a didChangeWorkspaceFolders notification whenever the user adds or removes a workspace folder.

How to test

Add/remove workspace folders in Theia and watch extensions with language servers get notified.

• as an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• as a reviewer, I agree to behave in accordance with the review guidelines

[kittaakos]

I do not understand this explicit vscode dependency. I can see monaco-languageclient also imports them.

[kittaakos]

I do not understand this explicit vscode dependency.

I see. They're from here: https://github.com/microsoft/vscode/blob/master/src/vs/vscode.d.ts#L8432-L8452.

[JanKoehnlein]

Sorry for the sloppy initial commit. I've changed the ready resolution and added the missing dev dependency on @types/vscode.

[JanKoehnlein]

I addressed your comments and re-implemented the workspaceFolder init/updated

[akosyakov]

@JanKoehnlein the build is failing, for some reasons it cannot find monaco namespace anymore

[JanKoehnlein]

I had this sporadically here, too. I guess we should not add a dependency to @types/vscode but define the WorkspaceFolder and WorkspaceFolderChangeEvent interfaces ourselves

[kittaakos]

Thanks for the updates, @JanKoehnlein. Once the build is green I am going to verify it with one or two VS Code LS extensions.

[kittaakos]

It throws an error at startup:

monaco-workspace.ts:214 Uncaught (in promise) TypeError: Cannot read property 'map' of undefined
    at MonacoWorkspace.push.../../packages/monaco/lib/browser/monaco-workspace.js.MonacoWorkspace.updateWorkspaceFolders (monaco-workspace.ts:214)
    at MonacoWorkspace.<anonymous> (monaco-workspace.ts:200)
    at step (monaco-workspace.ts:15)
    at Object.next (monaco-workspace.ts:15)
    at fulfilled (monaco-workspace.ts:15)

You get the value before you set it:
Get:

theia/packages/monaco/src/browser/monaco-workspace.ts

Line 214 in ecedb65

const oldWorkspaceUris = this.workspaceFolders.map(folder => folder.uri.toString());

Set:

theia/packages/monaco/src/browser/monaco-workspace.ts

Line 218 in ecedb65

this._workspaceFolders = newWorkspaceUris.map(this.toWorkspaceFolder);

[JanKoehnlein]

Wow. Looks like I should get more sleep. Initialization of the property with an empty array was missing.

[kittaakos]

From the LSP specs:

The workspace/workspaceFolders request is sent from the server to the client to fetch the current open list of workspace folders. Returns null in the response if only a single file is open in the tool. Returns an empty array if a workspace is open but no folders are configured.

If I open Theia without a workspace and then open a single file (e.g.: main.go), the monaco-workspace returns with an empty array instead of null. Note, the LS works.

[akosyakov]

@kittaakos MonacoWorkspace confirms to VS Code API, not to LSP, transformation from VS Code api to LSP happens here: https://github.com/microsoft/vscode-languageserver-node/blob/50ffd38681b3fc8dde75a70accfa3c29db1889f3/client/src/workspaceFolders.ts#L45-L53

Docs for VS Code APIs: https://github.com/microsoft/vscode/blob/c975df3b59ac221f70d525498ae6ff81bce77a10/src/vs/vscode.d.ts#L8515-L8519

Although It says the same 😄 WorkspaceService has opened getter to check whether a folder is opened.

[kittaakos]

I have tried it with the TS LS, and the vscode-go extension in the browser. I added then removed a few workspaces, even ones with whitespace in their names. It worked as expected: I had diagnostics and content assist support in my newly added workspaces. Thank you for the path patch 👍

[JanKoehnlein]

Thanks a lot for the reviews!