Summary:
- Using "System.getenv" allows to specify any entry file using environment variables and without modifying gradle file. Example:
export ENTRY_FILE="another_entry_file.js"
./gradlew assembleDebug
- This functionality is also more align with iOS implementation that uses 'if [[ "$ENTRY_FILE" ]]; then'. See https://github.com/facebook/react-native/pull/23667 for more details.
- Possibility to define entry file on CI without modifying sources (Example: project like [pixels-catcher](https://www.npmjs.com/package/pixels-catcher) requires different entry file)
## Changelog:
[Android] [Added] - Custom entry file on android using `ENTRY_FILE` environment variable
Pull Request resolved: https://github.com/facebook/react-native/pull/26769
Test Plan:
- Create a project from template
- Define `ENTRY_FILE` environment variable
```
export ENTRY_FILE="anotherIndexFile.js"
```
- Build android
```
./gradlew assembleDebug
```
Expected result: App contains bundle file that starts from `anotherIndexFile.js` file.
Differential Revision: D17903165
Pulled By: cpojer
fbshipit-source-id: 6b7cdf229918d101c170aa5fbdca6f3ef293d41c