R8 build failure with StreamPreviewDataUtils classes referenced from ComposableSingletons

[matteinn]

Describe the bug
When building with R8 enabled, I encounter build failures due to missing preview data utilities. The library includes stream-video-android-previewdata as compileOnly, but Compose generates ComposableSingletons classes that reference these preview utilities in production code.

ERROR: R8: Missing class io.getstream.video.android.mock.StreamPreviewDataUtils (referenced from: void io.getstream.video.android.compose.ui.components.call.renderer.internal.ComposableSingletons$ScreenShareVideoRendererKt$lambda-2$1.invoke(androidx.compose.runtime.Composer, int))

Missing class io.getstream.video.android.mock.StreamPreviewDataUtilsKt (referenced from: void io.getstream.video.android.compose.ui.components.call.ComposableSingletons$CallAppBarKt$lambda-7$1.invoke(androidx.compose.runtime.Composer, int) and 35 other contexts)

The automatically generated missing_rules.txt file doesn't work:

# Please add these rules to your existing keep rules in order to suppress warnings.
# This is generated automatically by the Android Gradle plugin.
-dontwarn io.getstream.video.android.mock.StreamPreviewDataUtils
-dontwarn io.getstream.video.android.mock.StreamPreviewDataUtilsKt

The only workaround I've found so far is including the preview module in runtime dependencies of the consumer app, even though it adds unnecessary code:

implementation("io.getstream:stream-video-android-previewdata:same-version")

Kotlin generates ComposableSingletons classes that contain lambda references to all Composable functions in a file, including those marked with @Preview. Even though preview functions like ScreenShareVideoRendererPreview() are marked private, the compiler still generates references to them that are accessible from production code.

Suggested Solutions

1. Move all preview-specific code to dedicated files in a preview source set that can be excluded from release builds
2. Change compileOnly dependency on stream-video-android-previewdata to api to ensure it's available in production
3. Modify the library to avoid using Preview Data Utils directly in Compose Previews, or provide comprehensive ProGuard rules

👉 The first approach is recommended to avoid shipping unnecessary code in production apps.

SDK version

• 1.6.3

To Reproduce
Steps to reproduce the behavior:

1. Include the Stream Video Compose UI library in an Android app
2. Enable R8
3. Try to build the app

Expected behavior
App builds fine.

Device:
Any

Screenshots
None

[aleksandar-apostolov]

Hi,

Thanks for the detailed report, we are partially aware of this issue.
We are planning on moving the previews outside of the implementation i.e. approach 1 in your comment.
This is a bit low on our priority list, I'll keep you posted.

Regards,
Alex

[matteinn]

@aleksandar-apostolov thank you!