index.tsx breaks release build of example app

[bllanos]

Environment

Output of react-native info (probably not relevant):

System:
    OS: Linux 5.4 Ubuntu 20.04.1 LTS (Focal Fossa)
    CPU: (12) x64 Intel(R) Core(TM) i7-10710U CPU @ 1.10GHz
    Memory: 340.42 MB / 15.34 GB
    Shell: 5.0.17 - /bin/bash
  Binaries:
    Node: 10.19.0 - /usr/bin/node
    Yarn: 1.22.4 - /usr/local/bin/yarn
    npm: 6.14.4 - /usr/bin/npm
    Watchman: Not Found
  SDKs:
    Android SDK: Not Found
  IDEs:
    Android Studio: Not Found
  Languages:
    Java: 14.0.1 - /usr/bin/javac
    Python: 2.7.18 - /usr/bin/python
  npmPackages:
    @react-native-community/cli: Not Found
    react: 16.11.0 => 16.11.0 
    react-native: 0.62.2 => 0.62.2 
  npmGlobalPackages:
    *react-native*: Not Found

Description

The example Android app builds in debug mode, but not in release mode. I get the following error when running yarn example android --variant=release:

yarn run v1.22.4
$ yarn --cwd example android --variant=release
$ react-native run-android --variant=release
info Running jetifier to migrate libraries to AndroidX. You can disable it using "--no-jetifier" flag.
Jetifier found 958 file(s) to forward-jetify. Using 12 workers...
info JS server already running.
info Installing the app...

> Task :app:bundleReleaseJsAndAssets FAILED
warning: the transform cache was reset.
Error: The resource `PROJECT_ROOT/example/index.js` was not found.
    at fs.realpath.err (PROJECT_ROOT/example/node_modules/metro/src/IncrementalBundler.js:157:26)
    at gotStat (fs.js:1600:21)
    at FSReqWrap.oncomplete (fs.js:153:21)

Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
Use '--warning-mode all' to show the individual deprecation warnings.
See https://docs.gradle.org/6.5/userguide/command_line_interface.html#sec:command_line_warnings
5 actionable tasks: 2 executed, 3 up-to-date
error The resource `PROJECT_ROOT/example/index.js` was not found. Run CLI with --verbose flag for more details.

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:bundleReleaseJsAndAssets'.
> Process 'command 'npx'' finished with non-zero exit value 1

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 6s

error Failed to install the app. Make sure you have the Android development environment set up: https://reactnative.dev/docs/environment-setup. Run CLI with --verbose flag for more details.
Error: Command failed: ./gradlew app:installRelease -PreactNativeDevServerPort=8081
error The resource `PROJECT_ROOT/example/index.js` was not found. Run CLI with --verbose flag for more details.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

Workaround/Solution

Rename example/index.tsx to example/index.js.

The reasoning behind this is that, "You should leave the ./index.js entrypoint file as it is otherwise you may run into an issue when it comes to bundling a production build." (https://reactnative.dev/docs/typescript)

Reproducible Demo

1. Run npx @react-native-community/bob create react-native-awesome-module and enter the following choices:

? What is the name of the npm package? react-native-awesome-module
? What is the description for the package? Description
? What is the name of package author? Name
? What is the email address for the package author? email@domain.com
? What is the URL for the package author? https://www.github.com/author
? What is the URL for the repository? https://www.github.com/author/repository
? What type of package do you want to develop? JavaScript module with native example

2. cd react-native-awesome-module/
3. Fix Android build fails #65
4. Run yarn bootstrap
5. Run yarn example android --variant=release

[bllanos]

Tangentially-related pull request: #6

[satya164]

The reasoning behind this is that, "You should leave the ./index.js entrypoint file as it is otherwise you may run into an issue when it comes to bundling a production build

That sounds more like an issue than a reasoning. I think we need to set the entryFile option in android/app/build.gradle