Parcel: Watch hangs / doesn't watch anymore in [email protected]

[ThreadPitt]

🐛 bug report

We use "parcel watch" with one entry point
All works fine, but seemingly at random, the watcher doesn't watch anymore, e.g. does not re-bundle when files are changed. There's no error message.

Mostly it seems to happen when previously there was an error while bundling.

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

"parcel watch .\js\main.js"

"devDependencies": {
"@babel/cli": "^7.2.3",
"@babel/core": "^7.3.4",
"@babel/plugin-proposal-class-properties": "^7.3.4",
"@babel/plugin-transform-strict-mode": "^7.2.0",
"@babel/preset-env": "^7.3.4",
"@babel/preset-react": "^7.0.0",
"babel-plugin-styled-components": "^1.10.0",
"browser-sync": "^2.26.3",
"react": "^16.8.4",
"react-dom": "^16.8.4"
},
"dependencies": {
"ag-grid-community": "^20.1.0",
"ag-grid-react": "^20.1.1",
"es6-promise": "^4.2.6",
"normalize.css": "^8.0.1",
"office-ui-fabric-react": "^6.151.0",
"prop-types": "^15.7.2",
"react-router-dom": "^4.3.1",
"styled-components": "^4.1.3",
"whatwg-fetch": "^3.0.0",
"yup": "^0.26.10"
}

{
"presets": [ "@babel/preset-env", "@babel/preset-react" ],
"plugins": [
"@babel/plugin-proposal-class-properties",
"babel-plugin-styled-components",
"@babel/plugin-transform-strict-mode"
]
}

💁 Possible Solution

We kill the process and start "parcel watch" again.

🌍 Your Environment

| Software | Version(s) |
| ---------------- | ---------- |
| Parcel | [email protected]
| Node | 8.12.0
| npm/Yarn | npm 6.4.1
| Operating System | Windows Server 2016

[garthenweb]

Can you try running it with the environment UV_THREADPOOL_SIZE=16? If this helps, it should be fixed with the next release. See https://github.com/parcel-bundler/parcel/pull/2452 for more information.

[WayneHiller]

I am having this issue too with a small vue.js project in VS 2019. It stops working after only a couple minutes. No errors. Like it stops detecting file changes.

Edit: I updated to parcel 1.12.0 and now I am getting this error after a few file change saves.

Building... at Bundler.createBundleTree (E:\Development\AIN 2\ABS\Setup\ABS Setup\node_modules\parcel-bundler\src\Bundler.js:719:12) at Bundler.createBundleTree (E:\Development\AIN 2\ABS\Setup\ABS Setup\node_modules\parcel-bundler\src\Bundler.js:719:12) at Bundler.bundle (E:\Development\AIN 2\ABS\Setup\ABS Setup\node_modules\parcel-bundler\src\Bundler.js:298:14) at process._tickCallback (internal/process/next_tick.js:68:7)

[ThreadPitt]

Can you try running it with the environment UV_THREADPOOL_SIZE=16? If this helps, it should be fixed with the next release. See #2452 for more information.

Thanks for the fast reply! I am not 100% sure where to set the environment variable in Windows so that it works with node.js/parcel properly.

I put it in Control Panel\System and Security\System -> [Advanced System Settings] -> [Environment Variables], but that does not seem to have resolved the issue 100%

[ThreadPitt]

Here a sample after which parcel hangs and doesn't "watch" anymore: I made an error when using the object syntax for styled components. The error is recognized properly and after that no more files are compiled/bundled.

(XXX) Unexpected token, expected "," (23:23)
const fileContainer = {
padding: '4px 10px';
^
};

[ThreadPitt]

Another hint that might be helpful: We are using Visual Studio (not VS Code), which probably also has watchers on the files and maybe they do interfere?

[WayneHiller]

Another hint that might be helpful: We are using Visual Studio (not VS Code), which probably also has watchers on the files and maybe they do interfere?

I found down grading to version 1.10.3 helped a lot. Now it only stops working when there is an error.

Edit: Well 1.10.3 does run for a bit longer but it still stops responding to file changes after a while. It is surprising how much more difficult development is without the watch feature :(

[ThreadPitt]

UPDATE: Using the latest version 1.12.3 we now do get an error every now and then:

Cannot read property 'type' of undefined
at Bundler.createBundleTree (C:\Users\xxx\AppData\Roamingnpmnode_modules\parcel-bundler\src\Bundler.js:654:54)
at Bundler.createBundleTree (C:\Users\xxx\AppData\Roamingnpmnode_modules\parcel-bundler\src\Bundler.js:721:12)
at Bundler.createBundleTree (C:\Users\xxx\AppData\Roamingnpmnode_modules\parcel-bundler\src\Bundler.js:721:12)
at Bundler.bundle (C:\Users\op.DEV\xxx\Roamingnpmnode_modules\parcel-bundler\src\Bundler.js:298:14)
at process._tickCallback (internal/process/next_tick.js:68:7)

Maybe this can help?

[jehkinen]

Have the same issue for Win10 and parcel-bundler 1.11.1

[ratfactor]

I my error is (nearly) identical to that posted by @ThreadPitt

$ parcel --version
1.12.3
$ parcel index.html
Server running at http://localhost:1234 
🚨  Cannot read property 'type' of undefined
    at Bundler.createBundleTree (/usr/lib/node_modules/parcel-bundler/src/Bundler.js:654:54)
    at Bundler.createBundleTree (/usr/lib/node_modules/parcel-bundler/src/Bundler.js:721:12)
    at Bundler.bundle (/usr/lib/node_modules/parcel-bundler/src/Bundler.js:298:14)
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:189:7)

The page serves fine at first, then I can cause the error with trivial changes (like commenting out a console.log() statement).

Platform: Slackware Linux and editing with Vim.

I see that /usr/lib/node_modules/parcel-bundler/src/Bundler.js:654:54 is in the if statement here:

// If the common bundle's type matches the asset's, move the asset to the common bundle.
// Otherwise, proceed with adding the asset to the new bundle below.
if (asset.parentBundle.type === commonBundle.type) {
    this.moveAssetToBundle(asset, commonBundle);
    return;
}

Thanks!

[dharmax]

Same issue.... Grrr

[WayneHiller]

@dharmax What editor are you using?

[dharmax]

Webstorn

On Mon, Jul 22, 2019, 10:46 PM Wayne Hiller [e-mail]
wrote:

@dharmax https://github.com/dharmax What editor are you using?

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[jehkinen]

This issue is not related to parcel bundler, it's related to safe-write on the webstorm IDE, I fixed that just
disabled safewrite
who faced with issue please read

https://github.com/parcel-bundler/parcel/issues/221

[WayneHiller]

@jehkinen It is related to parcel because parcel should be able to handle safe-writes, many system save that way. Webpack handles it no problem. Hopefully version 2.0 will fix the issue with the new c++ file monitor. Unfortunately we don't really know how long it will take for version 2.0 to get finished. I am ready to test version 2.0 as soon as it is at least somewhat operational.

[jehkinen]

@WayneHiller I agree, thank you

[DeMoorJasper]

Parcel 2 will no longer use chokidar... and U can work around this so no reason to keep this open afaik

[joestant]

We've just moved to the latest Version of Visual Studio 2019 Preview to work on .Net 5 and experiencing this issue. We didn't encounter this before in 2019. Is anyone else finding this?