[prompts][config]: fix source location resolution for top-level folders of a workspace

src/vs/workbench/contrib/chat/browser/chatAttachmentModel/chatInstructionsFileLocator.ts

@@ -63,21 +63,26 @@ export class ChatInstructionsFileLocator {
 		// otherwise for each folder provided in the configuration, create
 		// a URI per each folder in the current workspace
 		const { folders } = this.workspaceService.getWorkspace();
+		const workspaceRootUri = dirname(folders[0].uri);
 		for (const folder of folders) {
 			for (const sourceFolderName of sourceLocations) {
-				const folderUri = extUri.resolvePath(folder.uri, sourceFolderName);
-				result.push(folderUri);
-			}
-		}
+				// create the source path as a path relative to the workspace
+				// folder, or as an absolute path if the absolute value is provided
+				const sourceFolderUri = extUri.resolvePath(folder.uri, sourceFolderName);
+				result.push(sourceFolderUri);
 
-		// if inside a workspace, add the specified source locations inside the workspace
-		// root too, to allow users to use `.copilot/prompts` folder (or whatever they
-		// specify in the setting) in the workspace root
-		if (folders.length > 1) {
-			const workspaceRootUri = dirname(folders[0].uri);
-			for (const sourceFolderName of sourceLocations) {
-				const folderUri = extUri.resolvePath(workspaceRootUri, sourceFolderName);
-				result.push(folderUri);
+				// if not inside a workspace, we are done
+				if (folders.length <= 1) {
+					continue;
+				}
+
+				// if inside a workspace, consider the specified source location inside
+				// the workspace root, to allow users to use some (e.g., `.github/prompts`)
+				// folder as a top-level folder in the workspace
+				const workspaceFolderUri = extUri.resolvePath(workspaceRootUri, sourceFolderName);
+				if (workspaceFolderUri.fsPath.startsWith(folder.uri.fsPath)) {
+					result.push(workspaceFolderUri);
+				}
 			}
 		}