Default Android configuration fails out of the box

Environment

Tried on both a Pixel 3 XL and a Zebra TC52 (android) device.

“dependencies”: { “react”: “17.0.1”, “react-native”: “0.64.2” }, “devDependencies”: { “@babel/core”: “^7.12.9”, “@babel/runtime”: “^7.12.5”, “@callstack/nativepack”: “^1.4.2”, “@react-native-community/eslint-config”: “^2.0.0”, “babel-jest”: “^26.6.3”, “babel-loader”: “^8.2.2”, “eslint”: “7.14.0”, “jest”: “^26.6.3”, “metro-react-native-babel-preset”: “^0.64.0”, “react-test-renderer”: “17.0.1”, “terser-webpack-plugin”: “^5.1.3”, “webpack”: “^5.38.1” },

node version 15.3.0

Description

If I configure a new project for Windows/Android as described here: https://reactnative.dev/docs/environment-setup

Then make the changes described here: https://github.com/callstack/nativepack#installation--setup

I paste in the webpack.config.js template from here: https://github.com/callstack/nativepack/blob/main/templates/webpack.config.js

I can run the bundling server normally and create a bundle without any errors. However, when the app starts, I will receive the following error:

06-04 19:06:02.565  8033 10134 E unknown:ReactNative: Exception in native call from JS
06-04 19:06:02.565  8033 10134 E unknown:ReactNative: com.facebook.react.devsupport.JSException: Unexpected token '='. Expected an opening '(' before a method's parameter list.
06-04 19:06:02.565  8033 10134 E unknown:ReactNative:   at com.facebook.react.bridge.queue.NativeRunnable.run(Native Method)
06-04 19:06:02.565  8033 10134 E unknown:ReactNative:   at android.os.Handler.handleCallback(Handler.java:938)
06-04 19:06:02.565  8033 10134 E unknown:ReactNative:   at android.os.Handler.dispatchMessage(Handler.java:99)
06-04 19:06:02.565  8033 10134 E unknown:ReactNative:   at com.facebook.react.bridge.queue.MessageQueueThreadHandler.dispatchMessage(MessageQueueThreadHandler.java:27)
06-04 19:06:02.565  8033 10134 E unknown:ReactNative:   at android.os.Looper.loop(Looper.java:223)
06-04 19:06:02.565  8033 10134 E unknown:ReactNative:   at com.facebook.react.bridge.queue.MessageQueueThreadImpl$4.run(MessageQueueThreadImpl.java:226)
06-04 19:06:02.565  8033 10134 E unknown:ReactNative:   at java.lang.Thread.run(Thread.java:923)
06-04 19:06:02.565  8033 10134 E unknown:ReactNative: Caused by: com.facebook.jni.CppException: Unexpected token '='. Expected an opening '(' before a method's parameter list.
06-04 19:06:02.565  8033 10134 E unknown:ReactNative:
06-04 19:06:02.565  8033 10134 E unknown:ReactNative: no stack

If I then put the app into debug mode using the regular devtools menu, it will load fine. I believe this means that the react-native javascript engine is choking on something that Chrome thinks is fine?

Does this mean the babel loader configuration on the default template webpack.config.js is missing some important library? I don’t know how to run something like that down or I would try for you.

If I switch to the Hermes engine, the crash is fatal, killing the app and giving no useful (to me) information in the log.

I can run the same app in metro with no problems.

I went through this exercise because the other app I have been developing suddenly developed a fatal (Hermes) crash for no obvious reason. Turns out it was because I turned the devtools debug mode off . In other words, this same exact error. If I change that app from hermes to the default engine, I get the exact error and stack above.

Reproducible Demo

https://github.com/DaveWelling/reproNativePack.git

It looks like you can reproduce this error simply by following the default android configuration instructions (as I did in the repro above) and making sure your devtools debug mode is turned off on your device.

I also ran the repro above on a completely different windows machine this morning and reproduced the problem. I would try it on a Mac or Ubuntu, but I don’t have one here at my house.

[zamotany]

If you’re on Windows then this regex is not matching: https://github.com/callstack/nativepack/blob/main/templates/webpack.config.js#L183 Can you try replacing it with /node_modules(.*[/\\])+@callstack[/\\]nativepack/ and see if that helps?

[zamotany]

The PR is merged, so closing the issue.