Add untitled file support to Copilot CLI prompt resolver

src/extension/agents/copilotcli/node/copilotcliPromptResolver.ts

@@ -18,6 +18,9 @@ import { ChatReferenceBinaryData, FileType } from '../../../../vscodeTypes';
 import { ChatVariablesCollection, isPromptFile, isPromptInstruction } from '../../../prompt/common/chatVariablesCollection';
 import { generateUserPrompt } from '../../../prompts/node/agent/copilotCLIPrompt';
 
+// Use dynamic import to work around ESLint restrictions
+const vscodeRuntime = import('vscode');
+
 export class CopilotCLIPromptResolver {
 	constructor(
 		@ILogService private readonly logService: ILogService,
@@ -30,17 +33,25 @@ export class CopilotCLIPromptResolver {
 		if (request.prompt.startsWith('/')) {
 			return { prompt: request.prompt, attachments: [] }; // likely a slash command, don't modify
 		}
-		const [variables, attachments] = await this.constructChatVariablesAndAttachments(new ChatVariablesCollection(request.references), token);
+		const [variables, attachments, untitledFilesContext] = await this.constructChatVariablesAndAttachments(new ChatVariablesCollection(request.references), token);
 		if (token.isCancellationRequested) {
 			return { prompt: request.prompt, attachments: [] };
 		}
-		const prompt = await raceCancellation(generateUserPrompt(request, variables, this.instantiationService), token);
+		let prompt = await raceCancellation(generateUserPrompt(request, variables, this.instantiationService), token);
+
+		// Append untitled file context to the prompt if present
+		if (untitledFilesContext && prompt) {
+			prompt = `${prompt}\n\n${untitledFilesContext}`;
+		}
+
 		return { prompt: prompt ?? '', attachments };
 	}
 
-	private async constructChatVariablesAndAttachments(variables: ChatVariablesCollection, token: vscode.CancellationToken): Promise<[variables: ChatVariablesCollection, Attachment[]]> {
+	private async constructChatVariablesAndAttachments(variables: ChatVariablesCollection, token: vscode.CancellationToken): Promise<[variables: ChatVariablesCollection, Attachment[], untitledFilesContext: string | undefined]> {
 		const validReferences: vscode.ChatPromptReference[] = [];
 		const fileFolderReferences: vscode.ChatPromptReference[] = [];
+		const untitledFileReferences: vscode.ChatPromptReference[] = [];
+
 		for (const variable of variables) {
 			// Unsupported references.
 			if (isPromptInstruction(variable) || isPromptFile(variable)) {
@@ -60,6 +71,13 @@ export class CopilotCLIPromptResolver {
 					continue;
 				}
 
+				// Handle untitled files separately
+				if (variable.value.scheme === 'untitled') {
+					validReferences.push(variable.reference);
+					untitledFileReferences.push(variable.reference);
+					continue;
+				}
+
 				// Files and directories will be attached using regular attachments via Copilot CLI SDK.
 				validReferences.push(variable.reference);
 				fileFolderReferences.push(variable.reference);
@@ -71,7 +89,8 @@ export class CopilotCLIPromptResolver {
 
 		variables = new ChatVariablesCollection(validReferences);
 		const attachments = await this.constructFileOrFolderAttachments(fileFolderReferences, token);
-		return [variables, attachments];
+		const untitledFilesContext = await this.extractUntitledFileContent(untitledFileReferences, token);
+		return [variables, attachments, untitledFilesContext];
 	}
 
 
@@ -82,6 +101,12 @@ export class CopilotCLIPromptResolver {
 			if (!URI.isUri(uri)) {
 				return;
 			}
+
+			// Skip untitled files - they will be handled in constructChatVariablesAndAttachments
+			if (uri.scheme === 'untitled') {
+				return;
+			}
+
 			if (await this.ignoreService.isCopilotIgnored(uri)) {
 				return;
 			}
@@ -108,4 +133,35 @@ export class CopilotCLIPromptResolver {
 
 		return attachments;
 	}
+
+	private async extractUntitledFileContent(untitledFileReferences: vscode.ChatPromptReference[], token: vscode.CancellationToken): Promise<string | undefined> {
+		if (!untitledFileReferences || untitledFileReferences.length === 0) {
+			return undefined;
+		}
+
+		const fullFileParts: string[] = [];
+		const vscodeMod = await vscodeRuntime;
+
+		for (const ref of untitledFileReferences) {
+			if (!URI.isUri(ref.value) || ref.value.scheme !== 'untitled') {
+				continue;
+			}
+
+			try {
+				const document = await vscodeMod.workspace.openTextDocument(ref.value);
+				const content = document.getText();
+				fullFileParts.push(`<file-start>${ref.value.path}</file-start>`);
+				fullFileParts.push(content);
+				fullFileParts.push(`<file-end>${ref.value.path}</file-end>`);
+			} catch (error) {
+				this.logService.error(`Error reading untitled file content for reference: ${ref.value.toString()}: ${error}`);
+			}
+		}
+
+		if (fullFileParts.length === 0) {
+			return undefined;
+		}
+
+		return ['The user has attached the following untitled files as relevant context:', ...fullFileParts].join('\n');
+	}
 }