Updating `compatibility_date` causes deployment to fail

[garysassano]

What versions & operating system are you using?

index.js

import { launch } from "@cloudflare/playwright";

export default {
  async fetch(_request: Request, env: Env) {
    const browser = await launch(env.BROWSER);
    const page = await browser.newPage();

    await page.goto("https://demo.playwright.dev/todomvc");

    const TODO_ITEMS = ["buy some cheese", "feed the cat", "book a doctors appointment"];

    const newTodo = page.getByPlaceholder("What needs to be done?");
    for (const item of TODO_ITEMS) {
      await newTodo.fill(item);
      await newTodo.press("Enter");
    }

    const img = await page.screenshot();
    await browser.close();

    return new Response(img, {
      headers: {
        "Content-Type": "image/png",
      },
    });
  },
};

wrangler.jsonc

/**
 * For more details on how to configure Wrangler, refer to:
 * https://developers.cloudflare.com/workers/wrangler/configuration/
 */
{
	"$schema": "node_modules/wrangler/config-schema.json",
	"name": "cloudflare-playwright-screenshot",
	"main": "src/index.ts",
	"compatibility_flags": ["nodejs_compat_v2"],
	"compatibility_date": "2025-06-30",
	"workers_dev": true,
	"upload_source_maps": true,
	"observability": {
      "enabled": true
  	},
	"browser": {
	  "binding": "BROWSER"
	},
}

Please provide a link to a minimal reproduction

https://github.com/cloudflare/cloudflare-docs/blob/production/src/content/docs/browser-rendering/platform/playwright.mdx

Describe the Bug

If you update the compatibility_date flag to 2025-09-17, it breaks the deployment:

Uncaught Error: No such module "node:fs".
  imported from "index.js"
 [code: 10021]

In order to fix the error you have two options:

• Set compatibility_flags to nodejs_compat instead of nodejs_compat_v2
• Set compatibility_date to an older date like 2025-06-30 instead of 2025-09-17

Please provide any relevant error logs

No response

[petebacondarwin]

Ah!

This is because the new fs compatibility flag is only implicitly enabled by nodejs_compat and not nodejs_compat_v2.

workerd/src/workerd/io/compatibility-date.capnp

Lines 914 to 919 in fd37875

	enableNodeJsFsModule @105 :Bool
	$compatEnableFlag("enable_nodejs_fs_module")
	$compatDisableFlag("disable_nodejs_fs_module")
	$impliedByAfterDate(name = "nodeJsCompat", date = "2025-09-15");
	# Enables the Node.js fs module. It is required to use this flag with
	# nodejs_compat (or nodejs_compat_v2).

I guess we expected that since nodejs_compat_v2 is implied by nodejs_compat after 2024/09/23 (see

workerd/src/workerd/io/compatibility-date.capnp

Line 468 in fd37875

$impliedByAfterDate(name = "nodeJsCompat", date = "2024-09-23");

) then setting nodejs_compat_v2 would imply enable_nodejs_fs_module.

cc @jasnell / @anonrig

In any case, since you are using a new compat date, there is no point in using nodejs_compat_v2. So the resolution for you is to change that flag to be nodejs_compat.