feat(create-cloudflare): prompt user to correct the answer if the arg value is invalid

.changeset/shiny-files-jog.md

@@ -0,0 +1,5 @@
+---
+"create-cloudflare": minor
+---
+
+feat: prompt user to correct the answer if the arg value is invalid

packages/cli/interactive.ts

@@ -47,6 +47,8 @@ export type BasePromptConfig = {
 	helpText?: string;
 	// The value to use by default
 	defaultValue?: Arg;
+	// The error message to display if the initial value is invalid
+	initialErrorMessage?: string | null;
 	// Accept the initialValue/defaultValue as if the user pressed ENTER when prompted
 	acceptDefault?: boolean;
 	// The status label to be shown after submitting
@@ -141,7 +143,14 @@ export const inputPrompt = async <T = string>(
 
 	// Looks up the needed renderer by the current state ('initial', 'submitted', etc.)
 	const dispatchRender = (props: RenderProps, p: Prompt): string | void => {
-		const renderedLines = renderers[props.state](props, p);
+		let state = props.state;
+
+		if (state === "initial" && promptConfig.initialErrorMessage) {
+			state = "error";
+			props.error = promptConfig.initialErrorMessage;
+		}
+
+		const renderedLines = renderers[state](props, p);
 		return renderedLines.join("\n");
 	};
 

packages/create-cloudflare/e2e-tests/cli.test.ts

@@ -1,3 +1,5 @@
+import fs from "node:fs";
+import { basename } from "node:path";
 import { beforeAll, describe, expect } from "vitest";
 import { version } from "../package.json";
 import { getFrameworkToTest } from "./frameworkToTest";
@@ -133,30 +135,61 @@ describe.skipIf(experimental || frameworkToTest || isQuarantineMode())(
 		test({ experimental }).skipIf(process.platform === "win32")(
 			"Mixed args and interactive",
 			async ({ logStream, project }) => {
-				const { output } = await runC3(
-					[project.path, "--ts", "--no-deploy"],
-					[
-						{
-							matcher: /What would you like to start with\?/,
-							input: [keys.enter],
-						},
-						{
-							matcher: /Which template would you like to use\?/,
-							input: [keys.enter],
-						},
-						{
-							matcher: /Do you want to use git for version control/,
-							input: ["n"],
-						},
-					],
-					logStream,
+				const projectName = basename(project.path);
+				const existingProjectName = Array.from(projectName).reverse().join("");
+				const existingProjectPath = project.path.replace(
+					projectName,
+					existingProjectName,
 				);
+				const existingFilePath = `${existingProjectPath}/example.json`;
 
-				expect(project.path).toExist();
-				expect(output).toContain(`type Hello World Worker`);
-				expect(output).toContain(`lang TypeScript`);
-				expect(output).toContain(`no git`);
-				expect(output).toContain(`no deploy`);
+				try {
+					// Prepare an existing project with a file
+					fs.mkdirSync(existingProjectPath, { recursive: true });
+					fs.writeFileSync(existingFilePath, `"Hello World"`);
+
+					const { output } = await runC3(
+						[existingProjectPath, "--ts", "--no-deploy"],
+						[
+							// c3 will ask for a new project name as the provided one already exists
+							{
+								matcher:
+									/In which directory do you want to create your application/,
+								input: {
+									type: "text",
+									chunks: [project.path, keys.enter],
+									assertErrorMessage: `ERROR  Directory \`${existingProjectPath}\` already exists and contains files that might conflict. Please choose a new name.`,
+								},
+							},
+							{
+								matcher: /What would you like to start with\?/,
+								input: [keys.enter],
+							},
+							{
+								matcher: /Which template would you like to use\?/,
+								input: [keys.enter],
+							},
+							{
+								matcher: /Do you want to use git for version control/,
+								input: ["n"],
+							},
+						],
+						logStream,
+					);
+
+					expect(project.path).toExist();
+					expect(output).toContain(`type Hello World Worker`);
+					expect(output).toContain(`lang TypeScript`);
+					expect(output).toContain(`no git`);
+					expect(output).toContain(`no deploy`);
+				} finally {
+					fs.rmSync(existingFilePath, {
+						recursive: true,
+						force: true,
+						maxRetries: 10,
+						retryDelay: 100,
+					});
+				}
 			},
 		);
 
@@ -243,8 +276,9 @@ describe.skipIf(experimental || frameworkToTest || isQuarantineMode())(
 		test({ experimental }).skipIf(process.platform === "win32")(
 			"Going back and forth between the category, type, framework and lang prompts",
 			async ({ logStream, project }) => {
+				const testProjectPath = "/test-project-path";
 				const { output } = await runC3(
-					["/invalid-project-name", "--git=false", "--no-deploy"],
+					[testProjectPath, "--git=false", "--no-deploy"],
 					[
 						{
 							matcher: /What would you like to start with\?/,

packages/create-cloudflare/e2e-tests/helpers.ts

@@ -53,6 +53,11 @@ export type PromptHandler = {
 	matcher: RegExp;
 	input:
 		| string[]
+		| {
+				type: "text";
+				chunks: string[];
+				assertErrorMessage?: string;
+		  }
 		| {
 				type: "select";
 				target: RegExp | string;
@@ -117,6 +122,22 @@ export const runC3 = async (
 			currentDialog.input.forEach((keystroke) => {
 				proc.stdin.write(keystroke);
 			});
+		} else if (currentDialog.input.type === "text") {
+			// text prompt handler
+			const { assertErrorMessage, chunks } = currentDialog.input;
+
+			if (
+				assertErrorMessage !== undefined &&
+				!text.includes(assertErrorMessage)
+			) {
+				throw new Error(
+					`The error message does not match; Expected "${assertErrorMessage}" but found "${text}".`,
+				);
+			}
+
+			chunks.forEach((keystroke) => {
+				proc.stdin.write(keystroke);
+			});
 		} else if (currentDialog.input.type === "select") {
 			// select prompt handler
 

packages/create-cloudflare/src/helpers/args.ts

@@ -415,11 +415,14 @@ export const processArgument = async <Key extends keyof C3Args>(
 		disableTelemetry: args[key] !== undefined,
 		async promise() {
 			const value = args[key];
+			const error = promptConfig.validate?.(value) ?? null;
 			const result = await inputPrompt<Required<C3Args>[Key]>({
 				...promptConfig,
 				// Accept the default value if the arg is already set
-				acceptDefault: promptConfig.acceptDefault ?? value !== undefined,
+				acceptDefault:
+					promptConfig.acceptDefault ?? (value !== undefined && !error),
 				defaultValue: value ?? promptConfig.defaultValue,
+				initialErrorMessage: error,
 				throwOnError: true,
 			});