Vitest Error: No such module "pg-cloudflare" when using `@cloudflare/vitest-pool-workers`

[tmm]

Which Cloudflare product(s) does this pertain to?

Workers Vitest Integration

What versions & operating system are you using?

@cloudflare/vitest-pool-workers@0.8.12, wrangler@4.8.0, node@22.5.1, macOS 14.5

Please provide a link to a minimal reproduction

https://github.com/tmm/pg-cloudflare-issue

Describe the Bug

Using pg in simple test:

import { Pool } from "pg";
import { test } from "vitest";

test("default", async () => {
  const pool = new Pool({
    connectionString: "postgresql://postgres:postgres@localhost",
  });
  const result = await pool.query("SELECT $1::text as name", ["cloudflare"]);
  console.log(result.rows[0].name);
});

Test passes with the following config vitest.pass.config.mts:

export default {
  test: {
    poolOptions: {
      workers: {
	wrangler: { configPath: "./wrangler.jsonc" },
      },
    },
  },
};

Test fails with the following config vitest.fail.config.mts:

import { defineWorkersConfig } from "@cloudflare/vitest-pool-workers/config";

export default defineWorkersConfig({
  test: {
    poolOptions: {
      workers: {
        wrangler: { configPath: "./wrangler.jsonc" },
      },
    },
  },
});

Possible upstream fix: brianc/node-postgres#3407

Please provide any relevant error logs

❯ pnpm test:pass

> @ test:pass /Users/user/Desktop/worker
> vitest -c vitest.pass.config.mts


 DEV  v3.0.9 /Users/user/Desktop/worker

stdout | test/index.spec.ts > default
cloudflare

 ✓ test/index.spec.ts (1 test) 16ms
   ✓ default

 Test Files  1 passed (1)
      Tests  1 passed (1)
   Start at  23:21:49
   Duration  184ms (transform 16ms, setup 0ms, collect 23ms, tests 16ms, environment 0ms, prepare 32ms)

 PASS  Waiting for file changes...
       press h to show help, press q to quit

❯ pnpm test:fail

> @ test:fail /Users/user/Desktop/worker
> vitest -c vitest.fail.config.mts


 DEV  v3.0.9 /Users/user/Desktop/worker

[vpw:inf] Starting isolated runtimes for vitest.fail.config.mts...
[mf:wrn] The latest compatibility date supported by the installed Cloudflare Workers Runtime is "2025-04-05",
but you've requested "2025-04-07". Falling back to "2025-04-05"...
workerd/server/server.c++:3250: error: Fallback service failed to fetch module; exception = (unknown):-1: failed: std::exception: Uncaught JsExceptionThrown
stack: 1053983a7 1048b010f 104887c3b 1053a0c53 104b26913 104b26bef 1053966db 104b187a3 1055faf17 1055f93eb 1055f93eb 1055f9c4b 1057868f3 1055f93eb 1055f9c4b; spec = /?specifier=%2FUsers%2Fuser%2FDesktop%2Fworker%2Fnode_modules%2F.pnpm%2Fpg-cloudflare%401.1.1%2Fnode_modules%2Fpg-cloudflare%2Fdist%2Findex.js%3Fmf_vitest_no_cjs_esm_shim&referrer=%2FUsers%2Fuser%2FDesktop%2Fworker%2Fnode_modules%2F.pnpm%2Fpg%408.14.1%2Fnode_modules%2Fpg%2Flib%2Fstream.js%3Fmf_vitest_no_cjs_esm_shim&rawSpecifier=pg-cloudflare
 ❯ test/index.spec.ts (1 test | 1 failed) 8ms
   × default 4ms
     → No such module "Users/user/Desktop/worker/node_modules/.pnpm/pg@8.14.1/node_modules/pg/lib/pg-cloudflare".

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ Failed Tests 1 ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯

 FAIL  test/index.spec.ts > default
Error: No such module "Users/user/Desktop/worker/node_modules/.pnpm/pg@8.14.1/node_modules/pg/lib/pg-cloudflare".
 ❯ getStream Users/user/Desktop/worker/node_modules/.pnpm/pg@8.14.1/node_modules/pg/lib/stream.js?mf_vitest_no_cjs_esm_shim:41:34
 ❯ new Connection Users/user/Desktop/worker/node_modules/.pnpm/pg@8.14.1/node_modules/pg/lib/connection.js?mf_vitest_no_cjs_esm_shim:18:36
 ❯ new Client Users/user/Desktop/worker/node_modules/.pnpm/pg@8.14.1/node_modules/pg/lib/client.js?mf_vitest_no_cjs_esm_shim:49:7
 ❯ BoundPool.newClient Users/user/Desktop/worker/node_modules/.pnpm/pg-pool@3.8.0_pg@8.14.1/node_modules/pg-pool/index.js?mf_vitest_no_cjs_esm_shim:222:20
 ❯ BoundPool.connect Users/user/Desktop/worker/node_modules/.pnpm/pg-pool@3.8.0_pg@8.14.1/node_modules/pg-pool/index.js?mf_vitest_no_cjs_esm_shim:216:10
 ❯ BoundPool.query Users/user/Desktop/worker/node_modules/.pnpm/pg-pool@3.8.0_pg@8.14.1/node_modules/pg-pool/index.js?mf_vitest_no_cjs_esm_shim:403:10
 ❯ test/index.spec.ts:8:28
      6|   connectionString: "postgresql://postgres:postgres@localhost",
      7|  });
      8|  const result = await pool.query("SELECT $1::text as name", ["cloudflare"]);
       |                            ^
      9|  console.log(result.rows[0].name);
     10| });

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[1/1]⎯


 Test Files  1 failed (1)
      Tests  1 failed (1)
   Start at  23:22:42
   Duration  555ms (transform 12ms, setup 0ms, collect 51ms, tests 8ms, environment 0ms, prepare 113ms)

 FAIL  Tests failed. Watching for file changes...
       press h to show help, press q to quit

[tmm]

Known issue 😅

[jrf0110]

Hey there @tmm this should now be fixed as of https://www.npmjs.com/package/pg/v/8.15.0