create-react-native-library@latest: Modify turbo-modules generation

[jhugman]

Fixes #107

Now working with create-react-native-library@0.41.2

This adds kotlin detection and uses Kotlin if needed, or stays with Java: this adds two Kotlin files and an alternative build.gradle file.

It also adds more checks to the test-turbo-modules.sh script, tightening up podspec and Objective C files.

Finally we add documentation to getting-started.md and contributing-turbo-modules.md.

[jhugman]

@Johennes may also be interested in this PR.

[Johennes]

Thanks for taking this one. Looks like a lot of work. 💪

I tested this by regenerating @unomed/react-native-matrix-sdk with create-react-native-library@latest. The example app works for me on iOS but not on Android:

/Users/jm/Code/react-native-matrix-sdk/android/src/main/java/com/unomed/reactnativematrixsdk/ReactNativeMatrixSdkModule.java:11: error: cannot find symbol
public class ReactNativeMatrixSdkModule extends NativeReactNativeMatrixSdkSpec {

I do have the NativeReactNativeMatrixSdkSpec class output from RN's codegen though.

$ cat android/generated/java/com/unomed/reactnativematrixsdk/NativeReactNativeMatrixSdkSpec.java

/**
 * This code was generated by [react-native-codegen](https://www.npmjs.com/package/react-native-codegen).
 *
 * Do not edit this file as changes may cause incorrect behavior and will be lost
 * once the code is regenerated.
 *
 * @generated by codegen project: GenerateModuleJavaSpec.js
 *
 * @nolint
 */

package com.unomed.reactnativematrixsdk;

import com.facebook.proguard.annotations.DoNotStrip;
import com.facebook.react.bridge.ReactApplicationContext;
import com.facebook.react.bridge.ReactContextBaseJavaModule;
import com.facebook.react.bridge.ReactMethod;
import com.facebook.react.turbomodule.core.interfaces.TurboModule;
import javax.annotation.Nonnull;

public abstract class NativeReactNativeMatrixSdkSpec extends ReactContextBaseJavaModule implements TurboModule {
  ...

I didn't have a lot of time to dig into it tonight sadly.

[jhugman]

Hmm. This is annoying.

Could you run this from within your checked out ubrn directory, substituting the variables:

./scripts/test-turbo-modules.sh \
  --ubrn-config $YOUR_UBRN_CONFIG_FILE \
  --app-tsx $YOUR_APP_TSX_FILE \
  --builder-bob-version latest \
  --android \
  --ios \
  --keep-directory-on-exit \
  --force-new-directory \
  --slug @unomed/react-native-matrix-sdk \
  --ios-name ReactNativeMatrixSdk \
  "$DIRECTORY"

I am a bit confused why you're seeing java files in src/main/java/com/unomed/reactnativematrixsdk; I would expect you to see Kotlin.

[Johennes]

I am a bit confused why you're seeing java files in src/main/java/com/unomed/reactnativematrixsdk; I would expect you to see Kotlin.

Funnily I had the exact same thought overnight and dug into that this morning. What happened is I wanted to rm -r android/build before building the example app because I'm frequently getting build failures when switching between ubrn versions because of some cached build artifacts. However, I fat-fingered and deleted the entire android folder instead. That killed build.gradle which you're using to determine whether to generate Kotlin or Java.

I copied build.gradle over from a project freshly generated with create-react-native-library, reran the ubrn generation et voilà the Android build works. 🎉

So the issue was entirely on my part, apologies. 🤦‍♂️

It does feel slightly circular to read the Kotlin flag from a file that ubrn itself generates. I couldn't think of another way to do it either though and if people don't mess up the create-react-native-library generation like I did, things should be fine.

I also tested ubrn from this branch on the repo that I had generated with the old create-react-native-library version and things worked fine there on both platforms.

Thanks again for making ubrn work with the latest create-react-native-library!

[jhugman]

It does feel slightly circular to read the Kotlin flag from a file that ubrn itself generates. I couldn't think of another way to do it either though and if people don't mess up the create-react-native-library generation like I did, things should be fine.

I did consider checking in package.json for the creat-react-nativw-library version but couldn't see when they'd started adding versions. Also version number sniffing felt too much like useragent sniffing.

Thanks so much for re-testing. That is such a relief.

[jhugman]

Could you review this please @zzorba