[Android] Upcoming changes for libraries in React Native 0.73

[cortinico]

TL;DR

React Native 0.73 will depend on Android Gradle Plugin (AGP) 8.x. This will require all the libraries to specify a namespace in their build.gradle file. We added a compatibility layer for libraries that haven't specified a namespace, but please consider updating your libraries nonetheless.

Details

I'd like to share some of the upcoming changes that will happen in 0.73, which is still a bit far, but we'd rather start earlier rather than later.

React Native 0.73 will depend on Android Gradle Plugin (AGP) 8.x, which brings a lot of improvements for Android apps but also a series of notable changes.

Most importantly:

• App/Library Developers will now have to install and use Java 17
• Library Developers will have to specify a namespace in their build.gradle file.

Specifically, the last change is a breaking change and will make libraries that are not specifying a namespace incompatible with React Native 0.73 (your project won't build).

Support for namespace was added in AGP 7.3.x, which ships with React Native 0.71. Libraries that published a new version with a namespace declared for 0.71 or 0.72 don't need further update. So we invite library authors to do those changes as soon as possible so by the time 0.73 is out, most of the apps are adapted.

What you need to change

Library authors will have to update their android/build.gradle file as follows:

android {
+   namespace = "com.example.mylibrary"
    ...
}

and remove the package definition from their AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
-          package="com.example.mylibrary">
+          >
...
</manifest>

Compatibility Layer

We added a compatiblity layer inside React Native 0.73, that will make sure that namespace is configured for each libraries, even if you don't update the library. This will make sure 0.73 works also with older libraries that are not receiving may updates.
Still consider updating your library to keep up to date with the Android best practices.

Further reading

Official Google documentation on namespaces is here.

---

Please update your libraries whenever possible, adding the namespace declaration and let us know if this is creating any issues for you.

[a7medev]

@cortinico Does removing the package="com.example.mylibrary" part affect support for older versions of React Native?

[ngocle2497]

@cortinico Does removing the package="com.example.mylibrary" part affect support for older versions of React Native?

I tried to patch react-native-bootsplash package. it's work (RN 0.71.8)

[a7medev]

@MasonLe2497 What about versions older than that? RN 0.71 is already the latest available release. What about versions before 0.69?

[RafikiTiki]

@a7medev I verified this by using updated version of Repack in the Release & Debug builds of apps using RN71.x and RN67.x. So far no problems :)

EDIT: I take that back – I messed up while pointing to the new local build of Repack in RN67.x project. In RN67.x the build of the test app using Repack version with this change fails with the following bug (which, tbh, makes sense):

In the generated PackageList.java file instead of a valid import of Repack, undefined is placed as a package namespace:

- import com.callstack.repack.ScriptManagerPackage;
+ import undefined.ScriptManagerPackage;

This then leads to the next error: cannot find symbol ScriptManagerPackage

[ngocle2497]

@cortinico which min RN version can use this change?

[RafikiTiki]

Hey everybody, I double-checked the compatibility of this change with older versions of React Native, and unfortunately, it's not compatible with RN67.x. Sorry for the confusion 😞 . I already updated my old comment with details of what exactly fails.

This looks like a breaking change, and libraries should release a new major version targeting RN71 and higher.

[thymikee]

@RafikiTiki thanks for coming back with the feedback. This is likely due to the RN CLI not able to parse namespace for RN 0.67, as it was added for CLI v10 which targets RN 0.71: react-native-community/cli@5fbb536

If we want to stay compatible with RN version policy, we likely need to backport this to 0.70 at least. We could go further I guess, but I'd need @cortinico let me know if this even makes sense.

[a7medev]

@thymikee We develop an SDK for React Native and leaving all these versions behind can be a bit risky.
What is the best approach for supporting 0.73 while still being backward-compatible?

[cortinico]

What about versions older than that? RN 0.71 is already the latest available release. What about versions before 0.69?

For completeness, by the time 0.73 will be out, 0.72 and 0.71 will also be out which supports the namespace directive. I've been discussing with other library maintainers to understand if we want to recommended a snippet that would allow to selectively call namespace only on RN >= 0.71.

And yes, removing package="com.example.mylibrary" from the Manifest also has impact on libraries which are running on RN < 71. If you wish to retain the highest compatibility it's better to don't remove the package directive from the Manifest and add the namespace directive.
Sadly users on 0.71+ will see a warning on console mentioning that package="com.example.mylibrary" can be removed from the library manifest's file which is not really actionable.

[androideveloper]

Nice! Thanks for starting this @cortinico .
What about the R class being non-transitive by default? Have already caught a couple of libraries with incorrect refs.

The good part is that it helps to reduce the app size, especially for big projects 🎉

[gkasireddy202]

Hi,
I upgraded my project from 0.68.7 to 0.73.2. I am getting the below error on Android.
I do not want to upgrade my libraries in package.json
The project is using an incompatible version (AGP 8.1.1) of the Android Gradle plugin. Latest supported version is AGP 7.2.1.