The barcode model is two thirds of a default tool's APK

[jedbridges]

Noticed this while trimming my own tool and it seems worth flagging, since it
affects everything built on the SDK.

:sdk:ui includes LightQrCodeScanner, which pulls in ML Kit's barcode model.
libbarhopper_v3.so is 19.3MB of a 29MB release APK — about two thirds of the
download — and it ships for four ABIs on a phone that's arm64 only.

My tool doesn't scan anything, so I excluded it:

implementation(project(":sdk:client")) {
    exclude(group = "com.google.mlkit")
    exclude(group = "com.google.android.gms", module = "play-services-mlkit-barcode-scanning")
}

That took the APK from 29MB to 8.5MB and native libs from 19.51MB to 233KB. I
went through every screen on a debug build and again on a minified release
build — no missing classes, no crashes.

Two questions. Is excluding it reasonable, or am I working around something I
shouldn't be? And would it make sense for the scanner to be opt-in, so tools
that don't scan don't carry the model?

[dupontgu]

• excluding it is totally reasonable while we work towards the real solution
• and yes, we're going to move dependencies declaration from the build.gradle into lighttool.toml so they get added dynamically. End goal is to make it so tool devs don't mess with gradle at all. This has been on my personal todo list forever but I'll convert this into an issue.