feat: Multi-Directory Workspace Support (part 3: configuration in settings.json) (#5354)

Co-authored-by: Allen Hutchison <adh@google.com>

packages/core/src/utils/workspaceContext.ts

@@ -15,6 +15,8 @@ import * as path from 'path';
 export class WorkspaceContext {
   private directories: Set<string>;
 
+  private initialDirectories: Set<string>;
+
   /**
    * Creates a new WorkspaceContext with the given initial directory and optional additional directories.
    * @param initialDirectory The initial working directory (usually cwd)
@@ -22,11 +24,14 @@ export class WorkspaceContext {
    */
   constructor(initialDirectory: string, additionalDirectories: string[] = []) {
     this.directories = new Set<string>();
+    this.initialDirectories = new Set<string>();
 
     this.addDirectoryInternal(initialDirectory);
+    this.addInitialDirectoryInternal(initialDirectory);
 
     for (const dir of additionalDirectories) {
       this.addDirectoryInternal(dir);
+      this.addInitialDirectoryInternal(dir);
     }
   }
 
@@ -69,6 +74,33 @@ export class WorkspaceContext {
     this.directories.add(realPath);
   }
 
+  private addInitialDirectoryInternal(
+    directory: string,
+    basePath: string = process.cwd(),
+  ): void {
+    const absolutePath = path.isAbsolute(directory)
+      ? directory
+      : path.resolve(basePath, directory);
+
+    if (!fs.existsSync(absolutePath)) {
+      throw new Error(`Directory does not exist: ${absolutePath}`);
+    }
+
+    const stats = fs.statSync(absolutePath);
+    if (!stats.isDirectory()) {
+      throw new Error(`Path is not a directory: ${absolutePath}`);
+    }
+
+    let realPath: string;
+    try {
+      realPath = fs.realpathSync(absolutePath);
+    } catch (_error) {
+      throw new Error(`Failed to resolve path: ${absolutePath}`);
+    }
+
+    this.initialDirectories.add(realPath);
+  }
+
   /**
    * Gets a copy of all workspace directories.
    * @returns Array of absolute directory paths
@@ -77,6 +109,17 @@ export class WorkspaceContext {
     return Array.from(this.directories);
   }
 
+  getInitialDirectories(): readonly string[] {
+    return Array.from(this.initialDirectories);
+  }
+
+  setDirectories(directories: readonly string[]): void {
+    this.directories.clear();
+    for (const dir of directories) {
+      this.addDirectoryInternal(dir);
+    }
+  }
+
   /**
    * Checks if a given path is within any of the workspace directories.
    * @param pathToCheck The path to validate