Error: Bundles must have unique names

[jsjoeio]

🐛 bug report

During the migration from v1 to v2, Parcel seems to be unhappy with my bundles and I'm not sure why (nor sure how to fix them).

🎛 Configuration (.babelrc, package.json, cli command)

Not using a .babelrc file but heres' the code:

v1

  parcel build \
    --public-url "." \
    --out-dir dist \
    $([[ $MINIFY ]] || echo --no-minify) \
    src/browser/register.ts \
    src/browser/serviceWorker.ts \
    src/browser/pages/login.ts \
    src/browser/pages/vscode.ts

v2

  parcel build \
    --public-url "." \
    --dist-dir dist \
    $([[ $MINIFY ]] || echo --no-optimize) \
    src/browser/register.ts \
    src/browser/serviceWorker.ts \
    src/browser/pages/login.ts \
    src/browser/pages/vscode.t

🤔 Expected Behavior

Parcel 2 should bundle the files like Parcel 1 did (assuming the correct changes have been made).

😯 Current Behavior

Parcel is spitting out an error.

🚨 Build failed.
Error: Bundles must have unique names
AssertionError [ERR_ASSERTION]: Bundles must have unique names
    at BundlerRunner.nameBundles (/Users/jp/Dev/code-server/node_modules/@parcel/core/lib/requests/BundleGraphRequest.js:482:23)
    at processTicksAndRejections (internal/process/task_queues.js:95:5)
    at async BundlerRunner.bundle (/Users/jp/Dev/code-server/node_modules/@parcel/core/lib/requests/BundleGraphRequest.js:434:5)
    at async RequestTracker.runRequest (/Users/jp/Dev/code-server/node_modules/@parcel/core/lib/RequestTracker.js:694:20)
    at async Parcel._build (/Users/jp/Dev/code-server/node_modules/@parcel/core/lib/Parcel.js:661:25)
    at async Parcel.run (/Users/jp/Dev/code-server/node_modules/@parcel/core/lib/Parcel.js:510:18)
    at async run (/Users/jp/Dev/code-server/node_modules/parcel/lib/cli.js:367:7)

💁 Possible Solution

We thought it was because we had this line inside register.ts

import "./pages/error.css"
import "./pages/global.css"
import "./pages/login.css"

Sadly removing that did not solve the issue.

🔦 Context

We're trying to migrate from v1 to v2 because there are vulnerabilities in v1 and fixing them causing v1 to break so we're in a pickle 😅

💻 Code Sample

We use Parcel to bundle files for code-server (see here).

🌍 Your Environment

Software	Version(s)
Parcel	^2.0.0-beta.3.1
Node	v14.17.0
npm/Yarn	1.22.10
Operating System	macOS Big Sur 11.3

[mischnic]

Please tell me what commands I need to run after cloning your PR to reproduce this. I'm getting all sorts of errors when running yarn build

[jsjoeio]

I figured it might be easier to record a Loom and show the error and explain some context too (though it is not captioned. if that doesn't work, happy to write out more context here).

I'm getting all sorts of errors when running yarn build

Apologies about that. I don't want to have to ask you to work through various code-server issues to help us figure this out.

If the Loom video doesn't work, I would be happy to try and isolate this in a small repo. Let me know!

[mischnic]

The reason I tried to reproduce it is that the error message doesn't really say which bundles are involved. So in that sense, a small repo would be great.

What you could also do is adding a console.log just before the failing assertion:

parcel/packages/core/core/src/requests/BundleGraphRequest.js

Line 336 in 1ba0bd1

assert.deepEqual(

and retrieve the bundle names that way.

[jsjoeio]

What you could also do is adding a console.log just before the failing assertion:

That helped! For some reason, it's giving the bundles the same name using a filename in another part of the codebase 🤔

/Users/jp/Dev/code-server/out/node/entry.js

Reproduction

In other good news, I was able to create a small reproducible example.

1. git clone https://github.com/jsjoeio/parcel-v2-build-error.git
2. yarn
3. yarn build

[mischnic]

In case of your reproduction, the problem was this

diff --git package.json package.json
index 7978540..ac50166 100644
--- package.json
+++ package.json
@@ -1,7 +1,6 @@
 {
   "name": "parcel-v2-build-error",
   "version": "1.0.0",
-  "main": "index.js",
   "license": "MIT",
   "scripts": {
     "build": "./build.sh"

The "main" field should only be set if you're building a library. And in this case all of the entry points passed to Parcel were assigned index.js as output.

Not sure if that is also causing your original problem though

[jsjoeio]

Ah, interesting! We set the "main" field because we publish code-server as an npm package.

But we have a build script that copies the package.json and makes some changes so we can work around this v2 change.

FWIW, Parcel v1 didn't care about the "main" field (or at least this way worked). (see parcel-v1 branch in repro)

Thanks for helping us figure that out! Feel free to close this issue.

Also happy to submit another PR to the migration guide on the website if that would be helpful.

[mischnic]

FWIW, Parcel v1 didn't care about the "main" field

Correct

You can do this

{
  "main": "unrelated.js",
  "targets": {
    "main": false
  }
}

to make Parcel 2 ignore the main field:
https://v2.parceljs.org/configuration/package-json/#main-%2F-module-%2F-browser

[mischnic]

Also happy to submit another PR to the migration guide on the website if that would be helpful.

Would a short note about targets: {main: false} in https://v2.parceljs.org/getting-started/migration/#package.json%23main have helped you?

[jsjoeio]

FWIW, Parcel v1 didn't care about the "main" field

Correct

You can do this

{
  "main": "unrelated.js",
  "targets": {
    "main": false
  }
}

to make Parcel 2 ignore the main field:
https://v2.parceljs.org/configuration/package-json/#main-%2F-module-%2F-browser

Oh wow, that's even easier! Thanks for the tip!

[jsjoeio]

Would a short note about targets: {main: false} in https://v2.parceljs.org/getting-started/migration/#package.json%23main have helped you?

Definitely! That would have at least told me where our setup might break with V2.