fix: improve detection of Angular core version in monorepo setup (#2106)

* fix: improve detection of Angular core version in monorepo setup

Angular may not be installed at the project root. We should look for
`package.json` roots and determine the `@angular/core` version based on
these folders.

Related to: angular/angular#58546

* fixup! fix: improve detection of Angular core version in monorepo setup

Feedback

client/src/client.ts

@@ -227,7 +227,7 @@ export class AngularLanguageClient implements vscode.Disposable {
     }
 
     // Node module for the language server
-    const args = this.constructArgs();
+    const args = await this.constructArgs();
     const prodBundle = this.context.asAbsolutePath('server');
     const devBundle =
         this.context.asAbsolutePath(path.join('bazel-bin', 'server', 'src', 'server.js'));
@@ -289,7 +289,7 @@ export class AngularLanguageClient implements vscode.Disposable {
    * Construct the arguments that's used to spawn the server process.
    * @param ctx vscode extension context
    */
-  private constructArgs(): string[] {
+  private async constructArgs(): Promise<string[]> {
     const config = vscode.workspace.getConfiguration();
     const args: string[] = ['--logToConsole'];
 
@@ -317,8 +317,8 @@ export class AngularLanguageClient implements vscode.Disposable {
     }
 
     // Sort the versions from oldest to newest.
-    const angularVersions = getAngularVersionsInWorkspace().sort(
-        (a, b) => a.version.greaterThanOrEqual(b.version) ? 1 : -1);
+    const angularVersions = (await getAngularVersionsInWorkspace(this.outputChannel))
+                                .sort((a, b) => a.version.greaterThanOrEqual(b.version) ? 1 : -1);
 
     // Only disable block syntax if we find angular/core and every one we find does not support
     // block syntax
@@ -552,13 +552,22 @@ function extensionVersionCompatibleWithAllProjects(serverModuleLocation: string)
 }
 
 /**
- * Returns true if any project in the workspace supports block syntax (v17+).
+ * Traverses through the currently open VSCode workspace (i.e. all open folders)
+ * and finds all `@angular/core` versions installed based on `package.json` files.
  */
-function getAngularVersionsInWorkspace(): NodeModule[] {
+async function getAngularVersionsInWorkspace(outputChannel: vscode.OutputChannel):
+    Promise<NodeModule[]> {
+  const packageJsonFiles = await vscode.workspace.findFiles(
+      '**/package.json',
+      // Skip looking inside `node_module` folders as those contain irrelevant files.
+      '**/node_modules/**');
+  const packageJsonRoots = packageJsonFiles.map(f => path.dirname(f.fsPath));
   const angularCoreModules = new Set<NodeModule>();
-  const workspaceFolders = vscode.workspace.workspaceFolders || [];
-  for (const workspaceFolder of workspaceFolders) {
-    const angularCore = resolve('@angular/core', workspaceFolder.uri.fsPath);
+
+  outputChannel.appendLine(`package.json roots detected: ${packageJsonRoots.join(',\n  ')}`);
+
+  for (const packageJsonRoot of packageJsonRoots) {
+    const angularCore = resolve('@angular/core', packageJsonRoot);
     if (angularCore === undefined) {
       continue;
     }