C3: Relax empty directory check (#4226)

* C3: Relax empty directory check

* Adding tests

* Add pattern matching to allowedExistingFile check

.changeset/gentle-news-laugh.md

@@ -0,0 +1,5 @@
+---
+"create-cloudflare": patch
+---
+
+Relax empty directory check. Directories containing certain common config files and/or files created by an ide will be exempt from the pre-flight check

packages/create-cloudflare/src/__tests__/common.test.ts

@@ -1,6 +1,6 @@
 import * as command from "helpers/command";
 import { describe, expect, test, vi } from "vitest";
-import { isGitConfigured } from "../common";
+import { isAllowedExistingFile, isGitConfigured } from "../common";
 import { validateProjectDirectory } from "../common";
 
 function promisify<T>(value: T) {
@@ -71,3 +71,22 @@ describe("validateProjectDirectory", () => {
 		expect(validateProjectDirectory("f".repeat(59), args)).toBeUndefined();
 	});
 });
+
+describe("isAllowedExistingFile", () => {
+	const allowed = [
+		"LICENSE",
+		"LICENSE.md",
+		"license",
+		".npmignore",
+		".git",
+		".DS_Store",
+	];
+	test.each(allowed)("%s", (val) => {
+		expect(isAllowedExistingFile(val)).toBe(true);
+	});
+
+	const disallowed = ["foobar", "potato"];
+	test.each(disallowed)("%s", (val) => {
+		expect(isAllowedExistingFile(val)).toBe(false);
+	});
+});

packages/create-cloudflare/src/common.ts

@@ -39,10 +39,13 @@ export const validateProjectDirectory = (
 	// Validate that the directory is non-existent or empty
 	const path = resolve(relativePath);
 	const existsAlready = existsSync(path);
-	const isEmpty = existsAlready && readdirSync(path).length === 0; // allow existing dirs _if empty_ to ensure c3 is non-destructive
 
-	if (existsAlready && !isEmpty) {
-		return `Directory \`${relativePath}\` already exists and is not empty. Please choose a new name.`;
+	if (existsAlready) {
+		for (const file of readdirSync(path)) {
+			if (!isAllowedExistingFile(file)) {
+				return `Directory \`${relativePath}\` already exists and contains files that might conflict. Please choose a new name.`;
+			}
+		}
 	}
 
 	// Ensure the name is valid per the pages schema
@@ -67,6 +70,51 @@ export const validateProjectDirectory = (
 	}
 };
 
+export const isAllowedExistingFile = (file: string) => {
+	// C3 shouldn't prevent a user from using an existing directory if it
+	// only contains benign config and/or other files from the following set
+	const allowedExistingFiles = new Set([
+		".DS_Store",
+		".git",
+		".gitattributes",
+		".gitignore",
+		".gitlab-ci.yml",
+		".hg",
+		".hgcheck",
+		".hgignore",
+		".idea",
+		".npmignore",
+		".travis.yml",
+		".vscode",
+		"Thumbs.db",
+		"docs",
+		"mkdocs.yml",
+		"npm-debug.log",
+		"yarn-debug.log",
+		"yarn-error.log",
+		"yarnrc.yml",
+		".yarn",
+		".gitkeep",
+	]);
+
+	if (allowedExistingFiles.has(file)) return true;
+
+	const allowedExistingPatters = [
+		/readme(\.md)?$/i,
+		/license(\.md)?$/i,
+		/\.iml$/,
+		/^npm-debug\.log/,
+		/^yarn-debug\.log/,
+		/^yarn-error\.log/,
+	];
+
+	for (const regex of allowedExistingPatters) {
+		if (regex.test(file)) return true;
+	}
+
+	return false;
+};
+
 export const setupProjectDirectory = (args: C3Args) => {
 	// Crash if the directory already exists
 	const path = resolve(args.projectName);