[Parcel 2]: Bundle group cannot have more than one entry bundle of the same type

[TobiasSchikora]

🐛 bug report

Hi together,

I am switching from Parcel 1 to Parcel 2 with a larger project. With Parcel 1 there are no problems. Parcel 2 shows the following error message: Bundle group cannot have more than one entry bundle of the same type.

My entrypoints are assets/src/*/*.js. There are 3 folders in src: mobile, desktop and shared. When I try to import the same file from assets/src/shared folder in assets/src/desktop/aaa.js as well as in assets/src/mobile/bbb.js, then the error occurs.

I saw the following code part:

(0, _assert().default)(entryBundlesOfType.length === 1, // Otherwise, we'd end up naming two bundles the same thing.
      'Bundle group cannot have more than one entry bundle of the same type');

which aborts the bundle. Why? And why does this work in parcel 1 without any problems? What can I do?

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

"scripts": {
    "start": "npx parcel watch assets/src/*/*.js --public-url ../ --no-hmr",
    "build": "npx parcel build assets/src/*/*.js --no-source-maps --public-url ../"
  }

There is no difference if I use the --dist-dir cli option or the target in package.json.

🤔 Expected Behavior

The bundle should be created without any error messages. The files which were shared between desktop and mobile entrypoints should be in both entry output files. Parcel 1 does exactly what I expected.

😯 Current Behavior

The bundle aborts with an error message as follows:

AssertionError [ERR_ASSERTION]: Bundle group cannot have more than one entry bundle of the same type
    at Object.name (C:\mf\node_modules\@parcel\namer-default\lib\DefaultNamer.js:94:29)
    at BundlerRunner.nameBundle (C:\mf\node_modules\@parcel\core\lib\requests\BundleGraphRequest.js:494:39)
    at C:\mf\node_modules\@parcel\core\lib\requests\BundleGraphRequest.js:470:50
    at Array.map (<anonymous>)
    at BundlerRunner.nameBundles (C:\mf\node_modules\@parcel\core\lib\requests\BundleGraphRequest.js:470:31)
    at runMicrotasks (<anonymous>)
    at processTicksAndRejections (internal/process/task_queues.js:93:5)
    at async BundlerRunner.bundle (C:\mf\node_modules\@parcel\core\lib\requests\BundleGraphRequest.js:434:5)
    at async RequestTracker.runRequest (C:\mf\node_modules\@parcel\core\lib\RequestTracker.js:694:20)
    at async Parcel._build (C:\mf\node_modules\@parcel\core\lib\Parcel.js:661:25). 

🔦 Context

I try to share some modules between desktop and mobile (different) entrypoints. I have much entrypoints which are sharing some modules.

💻 Code Sample

assets/src/desktop/main.js import '../shared/components/autologin';

assets/src/mobile/main.js import '../shared/components/autologin';

assets/src/shared/components/autologin.js // some code

🌍 Your Environment

Software	Version(s)
Parcel	2.0.0-nightly.674
npm/Yarn	6.14.8 (npm)
Operating System	Windows 10 Pro (20H2)

[TobiasSchikora]

No, unfortunately this was not the problem :( Everytime when I inport the same file in more than one entrypoint, I got this message.

[mischnic]

Please provide a complete code example that produces this error

[TobiasSchikora]

That is, what causes the problem:

a.js

import { FuncOne } from './legacy/legacy';
import AnotherFunc from 'another.js';

b.js

import { FuncTwo } from './legacy';`

legacy.js

import AnotherFunc from 'another.js';
export FuncOne;
export FuncTwo;

CLI-Command is: npx parcel watch a.js b.js

[TobiasSchikora]

Is there a command or cli parameter to debug where exactly it crashes?

[TobiasSchikora]

Can somebody explain in which cases the message „Bundle group cannot have more than one entry bundle of the same type“ appears? Still looking for a solution :(

[TobiasSchikora]

Hi together,

I have uploaded a simplyfied version of my code which is not usable with parcel 2. My parcel cli command is: parcel watch src/*/*.js --dist-dir www/dist

The following link opens Google Drive (directory listing + download option):

https://drive.google.com/file/d/12A43L1qET1WjhY_uVGglF4yXAqzZTvfr/view?usp=sharing

I don't know if I do something wrong or this is a parcel 2 bug. In parcel 1 this example runs without any errors. Thanks for your help!

[TobiasSchikora]

It seems to be the same problem as described in https://github.com/parcel-bundler/parcel/discussions/5074

[lgarron]

I tried converting a project back to Parcel and am running into this. :-/

The output is really unhelpful, so I'm at a loss.

Repro:

git clone https://github.com/cubing/cubing.js && cd cubing.js
git checkout parcel-yet-again-again # 4a71add2091da6ab46dbf493f83a16d6d4d71428
npm install
make build-search-worker
npx parcel build src/sites/experiments-cubing-net/cubing-js/index.html

Output:

🚨 Build failed.

@parcel/namer-default: Bundle group cannot have more than one entry bundle of the same type

  AssertionError [ERR_ASSERTION]: Bundle group cannot have more than one entry bundle of the same type
  at Object.name
  (/Users/lgarron/Code/git/github.com/cubing/cubing.js/node_modules/@parcel/namer-default/lib/DefaultNamer.js:82:29)
  at BundlerRunner.nameBundle
  (/Users/lgarron/Code/git/github.com/cubing/cubing.js/node_modules/@parcel/core/lib/requests/BundleGraphRequest.js:346:39)
  at
  /Users/lgarron/Code/git/github.com/cubing/cubing.js/node_modules/@parcel/core/lib/requests/BundleGraphRequest.js:322:50
  at Array.map (<anonymous>)
  at BundlerRunner.nameBundles
  (/Users/lgarron/Code/git/github.com/cubing/cubing.js/node_modules/@parcel/core/lib/requests/BundleGraphRequest.js:322:31)
  at async BundlerRunner.bundle
  (/Users/lgarron/Code/git/github.com/cubing/cubing.js/node_modules/@parcel/core/lib/requests/BundleGraphRequest.js:283:5)
  at async RequestTracker.runRequest
  (/Users/lgarron/Code/git/github.com/cubing/cubing.js/node_modules/@parcel/core/lib/RequestTracker.js:711:20)
  at async Object.run
  (/Users/lgarron/Code/git/github.com/cubing/cubing.js/node_modules/@parcel/core/lib/requests/ParcelBuildRequest.js:57:21)
  at async RequestTracker.runRequest
  (/Users/lgarron/Code/git/github.com/cubing/cubing.js/node_modules/@parcel/core/lib/RequestTracker.js:711:20)
  at async Parcel._build
  (/Users/lgarron/Code/git/github.com/cubing/cubing.js/node_modules/@parcel/core/lib/Parcel.js:397:11)

Note that this works just fine for development:

npx parcel serve src/sites/experiments-cubing-net/cubing-js/index.html

(Also, the build process (but not the dev server) also runs into issues when folders have periods, so I renamed them for this repro.)

[lgarron]

I tried converting a project back to Parcel and am running into this. :-/

The output is really unhelpful, so I'm at a loss.

This is still a major issue for us.

I just tried 2.0.0-nightly.850 and we still get the same issue.

[TobiasSchikora]

Same here. Major issue. We can't update :'(

[jlkawlfj]

My files(entry points) were in the /src/pages/ folder and I was getting the this error, but when I moved all the entry points to /src/ it worked. I waiting fix.

before: "build": "parcel build src/pages/.jsx " after: "build": "parcel build src/.jsx "

[TobiasSchikora]

In the meantime it is the end of 2021 and there is still no feedback. We still have to use Parcel 1 because of this bug.

I have uploaded a code example to https://drive.google.com/file/d/12A43L1qET1WjhY_uVGglF4yXAqzZTvfr/view?usp=sharing.

My Parcel command is: parcel watch src/*/*.js --dist-dir www/dist.

Please help! We would love to update to Parcel 2.

[mischnic]

In @TobiasSchikora's case the problem is that it generates a shared CSS bundle, and one CSS bundle specific to just one of the entries. And because doing parcel build something.js generates something.js and something.css if there is a CSS import inside, there would be two something.css in this case.

[TobiasSchikora]

How does Parcel 1 handle this? (There are no problems). Do you think that this issue can be solved? I really love Parcel.

[mischnic]

Apparently it doesn't create a shared bundle.

[2silver]

Do you have any - maybe the same - browserlist/target configurations?

package.json

  "targets": {
    "mobile": {
      "engines": {
        "browsers": "> 0.5%, last 2 versions, not dead"
      }
    },
    "desktop": {
      "engines": {
        "browsers": "> 0.5%, last 2 versions, not dead"
      }
    }
  },

[windware-ono]

Is there a way to avoid this error?

I have this package.json targets with no other directives than package dependencies,

	"targets": {
		"site": {
			"source": "site/bundle.js",
			"distDir": "site/root/asset/",
			"publicUrl": "/asset/"
		},
		"admin": {
			"source": "admin/bundle.js",
			"distDir": "admin/root/asset/",
			"publicUrl": "/asset/"
		}
	},

and both of bundle.js have these lines

require('../style/*.styl')
require('./style/*.styl')

The former is a shared style files pointing to a same folder for both targets and the latter is local style files which differs for each targets.

Funny thing is that if there are no files in the local ./style/ folder, then somehow it bundles without an error but if I have a file in there, it errors with group bundle error but in that case if I remove the former shared style from being bundled, it works.

[jptissot]

Just ran into this as well. My setup is a bit different.

I was trying to use a glob pattern to build multiple package.json files under a folder.

 "scripts": {
    "watch": "parcel build apps/*'",

This gave the error above. The same thing occurs if I have a single package.json that has multiple targets.

[danbrellis]

Same issue for me as well with parcel 2.6.2

cli parcel watch 'modules/*.(js|scss)'

modules/a.js

import "./styles/a.scss
import * as helper from "components/helper";

helper.helper();

modules/b.js

import "./styles/b.scss
import * as helper from "components/helper";

helper.helper();

components/helper.js

import "./x-scroll.scss";
 exports.helper = () => {}
exports.helper();

When I remove the scss import from either a.js or b.js the error goes away.

[TobiasSchikora]

It seems that there is no interest to fix this :'(

[danbrellis]

@mischnic - do you have thoughts on a workaround (somehow disable shared bundles) or some indication if this would be addressed? Happy to help in any way I can!

[judd-pathoftrees]

I came across this issue when debugging a similar problem: I have two targets with different sources; js modules imported into each source were added to a shared bundle and only written to the output directory of the first target.

I was able to work around the problem by increasing the value of minBundles, as described under shared bundle configuration, to prevent the shared bundle being created (hat tip to @danbrellis for the 'disable shared bundles' idea).

This doesn't fix the original bug report, though I did get @TobiasSchikora's example to run by inlining the shared css import using transformer-inline as described at bundle inlining. However, running parcel build on this edited example causes Terser to throw a 'no file' error unless --no-optimize is used. It's hard to tell from the example if this is a viable workaround, but it could be worth exploring.

[richardkmichael]

I have this problem migrating a project to Parcel 2 as well.

I'm not familiar with the project's entry points, but based on @2silver hint, I naively removed the package.json browserslist config and now Parcel runs. I guess that's my starting point for entry point investigation.

[dsibinski]

I'm also facing this issue. The scenario is a bit different, but it's probably the same cause.

I have several sources defined in package.json:

"source": [
    "src/appsEntries/app1.ts",
    "src/appsEntries/app2.ts",
    "src/appsEntries/app3.ts"
  ]

Now I have two React files:

• Layout.tsx, which is used by all sources
• Component.tsx, which is used in the tree by app1.ts and app2.ts

In Layout.tsx I import a common.styles.scss file:

// Layout.tsx
import "./common.styles.scss";

and in Component.tsx file I import a different styles file, another.scss:

// Component.tsx
import "../../assets/another.scss";

when building with parcel I'm getting an error:

🚨 Build failed.

@parcel/namer-default: Bundle group cannot have more than one entry bundle of the same type

  AssertionError [ERR_ASSERTION]: Bundle group cannot have more than one entry bundle of the same type
      at Object.name (C:\my-web-app\node_modules\@parcel\namer-default\lib\DefaultNamer.js:82:29)
      at BundlerRunner.nameBundle (C:\my-web-app\node_modules\@parcel\core\lib\requests\BundleGraphRequest.js:402:39)
      at C:\my-web-app\node_modules\@parcel\core\lib\requests\BundleGraphRequest.js:378:50
      at Array.map (<anonymous>)
      at BundlerRunner.nameBundles (C:\my-web-app\node_modules\@parcel\core\lib\requests\BundleGraphRequest.js:378:31)
      at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
      at async BundlerRunner.bundle (C:\my-web-app\node_modules\@parcel\core\lib\requests\BundleGraphRequest.js:341:7)
      at async Object.run (C:\my-web-app\node_modules\@parcel\core\lib\requests\BundleGraphRequest.js:156:17)
      at async RequestTracker.runRequest (C:\my-web-app\node_modules\@parcel\core\lib\RequestTracker.js:756:20)
      at async Object.run (C:\my-web-app\node_modules\@parcel\core\lib\requests\ParcelBuildRequest.js:56:7)

I'm attaching a sample app which reproduces this error: parcel-scss-issue.zip

Run npm install, then npm run build to see the error.

This is problematic, as it doesn't allow splitting styles in this use scenario 😥 It would be great if there's a configuration option to either disable the same bundles names for specific cases or somehow override it.

[crummy]

For what it's worth, I've changed to Vite which seems to support this relatively easily.

Here's my vite.config.ts:

import {defineConfig} from 'vite'
import react from '@vitejs/plugin-react-swc'
import * as path from "path";

// https://vitejs.dev/config/
export default defineConfig(({mode}) => ({
    plugins: [react()],
    build: {
        manifest: true,
        rollupOptions: {
            input: {
                foo: __dirname + '/src/foo/index.tsx',
                bar: __dirname + '/src/bar/index.tsx',
                // ...etc
            },
        },
    },
}))

We have a dozen or so entry points and it's all straightforward.

[lol768]

We also unfortunately moved to Vite.

[jondlm]

#9023 might fix this issue also.

[tcmulder]

Any progress on this? Running into the same issue: "Bundle group cannot have more than one entry bundle of the same type" when trying to import the same file via separate entry points.

[lol768]

Hate to say it, but my solution was just to move to Vite

[tcmulder]

For now, I'm bypassing the issue by creating a separate file that imports the file I'm after. Using @TobiasSchikora 's filename examples, assets/src/shared still contains the shared things I want in both aaa and bbb, but I don't import them directly into assets/src/desktop/aaa.js and assets/src/desktop/bbb.js: instead, assets/src/desktop/aaa.js imports assets/src/desktop/aaa-shared.css and assets/src/desktop/bbb.js imports assets/src/desktop/bbb-shared.css, both of which are simply:

@import "../shared/*.css";

Parcel seems fine with this since both imports get to the same files via different paths 🤷‍♂️

It works for my use case which is just for reused CSS files (haven't tried this with JavaScript), though it's a bit ugly, and may not work for more complex needs. Still, it lets me just write my shared code once and import into aaa and bbb (with only a couple new lines/files I set up once and don't need to touch again) which is what I'm after.