`bundle` produces invalid entrypoint on Windows

Describe the bug

Running yarn bundle on Windows produces an entrypoint.js file that uses a backslash causing the script to crash.

This is due to the use of the path module and its sep value https://github.com/ojkelly/yarn.build/blob/e47d1197d5a02bd4f7f92a3d0b262cc00f2ceed2/packages/plugins/plugin-build/src/commands/bundle/index.ts#L387-L388 producing this output:

"use strict";

const pnp = require("./.pnp.cjs").setup();

const index = require("./.\register.js");

Object.defineProperty(exports, "__esModule", { value: true });

exports.default = index;

To Reproduce

Run the following in Git Bash on Windows

set -ex

cd $(mktemp -d)

yarn init -2
yarn plugin import https://yarn.build/latest

touch register.js
printf '{"main": "register.js"}' > package.json

TARGET="$(mktemp -d)"
yarn bundle --no-compress --output-directory "$TARGET"
node "$TARGET/entrypoint.js"

Expected behavior

The entrypoint should use a forward slash to ensure it works on Windows

Desktop (please complete the following information):

• OS: Windows 10

[ojkelly]

Thanks for this @merceyz. I don’t develop or deploy on Windows, but there’s been a number of Windows specific improvements and fixes thanks to @misterjoshua. Including our E2E tests on Windows.

in #135 I’ve had a start at a proper fix, and updated the windows test to confirm.

[merceyz]

require supports mixing \ and / on Windows so just using the POSIX relative path would work.