[commonjs] TypeScript compiled type-only modules render invalid bundles

[willmtemple]

I have some time/resources to take a crack at writing a patch for this if any maintainers can give me some pointers about where to go digging.

• Rollup Plugin Name: commonjs
• Rollup Plugin Version: ^17.1.0
• Rollup Version: ^2.40.0
• Operating System (or Browser): Building on Linux and Windows, testing in Chrome Headless
• Node Version: 14.15.5
• Link to reproduction (⚠️ read below): https://github.com/willmtemple/ot-commonjs-repro

Expected Behavior

Bundling the following code for use in browser testing should work as expected, or should throw an error/warning indicating that the bundle may have failed:

import { TraceFlags } from "@opentelemetry/api";

console.log(TraceFlags);

(TraceFlags is an enum.)

Actual Behavior

The bundle contains invalid references to exports in the inlined OpenTelemetry code, causing the bundle to throw:

  Uncaught ReferenceError: exports is not defined
  at dist-test/index.browser.js:298:24

  ReferenceError: exports is not defined
      at dist-test/index.browser.js:298:24
      at dist-test/index.browser.js:3:2
      at dist-test/index.browser.js:4:2

The stack trace refers to the line:

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

On this line, exports is not bound to any variable declaration. The module that generated this line comes from a type-only module, and this is the only line of code in the module (other than "use strict";).

Additional Information

I have provided a reproduction of this issue with some instructions at https://github.com/willmtemple/ot-commonjs-repro. UPDATE: This bug apparently occurs with any type only modules, so I renamed the issue accordingly, and I changed the repro repo to use an example dependency package that has only a type-only module. @opentelemetry/api just happens to be such a module.

The repro repo contains instructions and a few notes about things I've (unsuccessfully) tried. My guess is that this is tied up in the logic that plugin-commonjs uses to decide that the module is a "restorable" ESM using the __esModule sentinel.

[niklasf]

This bug applies to IIFE bundles as well.

[witemple-msft]

CC @bterlson

[shellscape]

We're using BuilderProgram so that must be outputting something that commonjs is picking up on. That's the only idea I have for you at the moment.

[witemple-msft]

@shellscape Did some digging through the code and found that this was fixed in #816. Is there a timeline for releasing this?

[shellscape]

At the moment plugin publishes are performed when we have a moment to do them. You'll notice by the commit history in the repo that we had a spate of them not too long ago, followed by a recent merge party of PRs. In the future we might implement a more on-demand publishing setup, but right now we do some auditing for each version. Consult the commit history for typical times between merge and publish.

[benduran]

Subscribed for updates. Trying to migrate a multi-application monorepo away from CRA to using Vite, and this is a blocker for us at the moment 🤕 (since Vite is using Rollup under the hood)

[stale]

Hey folks. This issue hasn't received any traction for 60 days, so we're going to close this for housekeeping. If this is still an ongoing issue, please do consider contributing a Pull Request to resolve it. Further discussion is always welcome even with the issue closed. If anything actionable is posted in the comments, we'll consider reopening it. ⓘ

[canadaduane]

This was fixed by #816 (I'm not sure what version of @rollup/plugin-commonjs that was merged in to, but I've tested 21.0.1 and it works).