Merge #8995

8995: fix: Create tasks for all workspaces r=matklad a=SomeoneToIgnore

Follow-up of https://github.com/rust-analyzer/rust-analyzer/pull/8955#discussion_r637897170

Before: 
<img width="593" alt="image" src="https://user-images.githubusercontent.com/2690773/119575267-712b5300-bdbf-11eb-833c-f688f7a7dd0f.png">

After: 
<img width="643" alt="image" src="https://user-images.githubusercontent.com/2690773/119575273-74264380-bdbf-11eb-8283-a78bbcb7346e.png">

This is the first time I've used multiple workspaces feature in VSCode, but so far looks like
* opening detached files works
* run and debug lens work
* Rust Analyzer: Run action works
* run task works and now shows tasks for all workspaces
* there are no platform-specific changes involved

Co-authored-by: Kirill Bulatov <[email protected]>

1 files changed, 3 insertions, 4 deletions

diff --git a/editors/code/src/main.ts b/editors/code/src/main.ts
index b735186fe..d26273246 100644
--- a/editors/code/src/main.ts
+++ b/editors/code/src/main.ts
@@ -45,8 +45,7 @@ async function tryActivate(context: vscode.ExtensionContext) {
         throw new Error(message);
     });
 
-    const workspaceFolder = vscode.workspace.workspaceFolders?.[0];
-    if (workspaceFolder === undefined) {
+    if (vscode.workspace.workspaceFolders?.length === 0) {
         const rustDocuments = vscode.workspace.textDocuments.filter(document => isRustDocument(document));
         if (rustDocuments.length > 0) {
             ctx = await Ctx.create(config, context, serverPath, { kind: 'Detached Files', files: rustDocuments });
@@ -58,8 +57,8 @@ async function tryActivate(context: vscode.ExtensionContext) {
         // registers its `onDidChangeDocument` handler before us.
         //
         // This a horribly, horribly wrong way to deal with this problem.
-        ctx = await Ctx.create(config, context, serverPath, { kind: "Workspace Folder", folder: workspaceFolder.uri });
-        ctx.pushCleanup(activateTaskProvider(workspaceFolder, ctx.config));
+        ctx = await Ctx.create(config, context, serverPath, { kind: "Workspace Folder" });
+        ctx.pushCleanup(activateTaskProvider(ctx.config));
     }
     await initCommonContext(context, ctx);