pg 8.22.0 CJS entry can resolve pg-protocol as ESM under Cloudflare/Vite worker tests

从 pg/lib/connection.js 开始，检查 CommonJS 入口如何解析 pg-protocol、pg-pool 和 pg-connection-string 的入口点。使用 @cloudflare/vitest-pool-workers 和 Vite 的 worker-test 流程复现该故障，然后验证 CommonJS 入口能够加载兼容的依赖文件，而不依赖 pnpm 的布局。

Summary

When pg@8.22.0 is bundled by the @cloudflare/vitest-pool-workers / Vite worker-test pipeline in a pnpm workspace, the CommonJS entry can fail while loading pg-protocol from pg/lib/connection.js:

SyntaxError: Cannot use import statement outside a module
  at node_modules/.pnpm/pg@8.22.0/node_modules/pg/lib/connection.js?mf_vitest_no_cjs_esm_shim:5:30
  at node_modules/.pnpm/pg@8.22.0/node_modules/pg/lib/client.js?mf_vitest_no_cjs_esm_shim:10:20
  at node_modules/.pnpm/pg@8.22.0/node_modules/pg/lib/index.js

The failing line is the CommonJS package-name require:

const { parse, serialize } = require("pg-protocol")

In this environment, that dependency can be resolved/transformed as an ES module, then loaded from a CJS wrapper.

Environment

• pg: 8.22.0
• pg-protocol: 1.15.0
• package manager: pnpm
• test/bundler stack: @cloudflare/vitest-pool-workers + Vite + Miniflare/workerd
• worker compatibility flag: nodejs_compat

Local workaround

We currently patch pg to force the CJS files to load the CJS dependency files directly from pnpm's sibling layout:

-const { parse, serialize } = require("pg-protocol")
+const { parse, serialize } = require("../../pg-protocol/dist/index.js")

-const Pool = require("pg-pool")
+const Pool = require("../../pg-pool/index.js")

-const parse = require("pg-connection-string").parse
+const parse = require("../../pg-connection-string/index.js").parse

That patch is not a good general solution because it depends on pnpm's installed package layout.

Ask

Would pg consider an upstream change that makes the CommonJS entry robust in bundler/worker environments, for example by ensuring the CJS entry always resolves CJS-compatible dependency entrypoints for pg-protocol, pg-pool, and pg-connection-string?

Happy to provide more details or test a candidate fix.