JS bundle isn't included in Android production build with Gradle 3.4

[thib92]

React Native version: 0.59.8

Steps To Reproduce

1. Open Android-Studio and update com.android.tools.build:gradle to 3.4.1 in the main Gradle file
2. Sync Gradle
3. Try to build an APK and install it on an Android Simulator (adb install)
4. See the app crash
5. Run adb logcat to get the logs of the Android Simulator
6. See the exception saying Unable to load script from assets 'index.android.bundle'

I encountered the issue and it was fixed by downgrading to 3.3 (see this reply).

Reason of the issue

The explanation in this comment:

Apparently, Gradle 3.2.0 changed the location to which it generates asset bundles. RN expects its JS asset bundle to be in a specific path, which is the path used by Gradle 3.1.4. Because G3.2.0 puts them in a different spot, RN cannot find the JS asset bundle, and thus the files with the Javascript to run. Ergo, the crash in release mode.

Possible fix

I think it would be a good idea to change the default JS bundle path in react.gradle.

WDYT? If this is a good fix, I'd be happy to try and implement it.

[wildseansy]

My workaround for this was to move the index.android.bundle from app/build/generated to app/src/main/assets, and then run gradle again to bundle this in.

Do this at your own risk, it definitely took some pain to figure this out, and may have unforeseen consequences

I run this to generate a release:

# Run in android directory:
rm -rf ./app/build/outputs/apk/production
rm -rf ./app/build/generated/assets
./gradlew assembleRelease
cp ./app/build/generated/assets/react/production/release/index.android.bundle ./app/src/main/assets/index.android.bundle
./gradlew assembleRelease

[thib92]

@wildseansy I’ve seen this workaround as well, but I’m not a big fan as you’re adding a bundle to the src directory, which is in source control, which mean you have to modify your gitignore file etc.

[wildseansy]

@thib92 - for sure. I just haven't found a better way yet, and downgrading will come at a cost to me after having integrated some React Hooks. Hope this can be resolved 👍

[thib92]

I use hooks in my app and downgrading to Gradle 3.1.4 didn't cause any problem 😊
But anyway I think it would be great if this could be fixed on the RN side!

[wildseansy]

Ah, I see - I had assumed downgrading Gradle would mean also bumping RN down, which would cascade to React being bumped down.

[thib92]

Fortunately it doesn't look like it 😄

[guhungry]

Duplicated with #24854
As #24854 (comment) said it was fixed in master.

[thib92]

@guhungry I didn’t see it had been fixed on master! Thanks!

[anmol-appzoy]

Hi folks, having the same issue with react-native - 0.58.6 and Gradle version - 4.7. Can someone please look into the issue and help me out in this.

[guhungry]

It was fixed in 0.59 so you have to upgrade React Native or search for workaround which i can't remember where i found it.