java_resource_extractor exclusion lists miss entries that AGP strips by default (KMP klib metadata, root LICENSE/NOTICE files)

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
78/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Quiet
Tech stack
android, kotlin, python
Domain
build-system, mobile

Research direction

Start in src/tools/java_resource_extractor/resource_extractor.py by reading the existing resource exclusion lists and comparing them with the entries named in the issue. Update the filtering so .knm, .kotlin_metadata, linkdata/, and root LICENSE.txt/NOTICE.txt are excluded, while META-INF/*.kotlin_module remains included; verify the resulting APK contents.

Written by the indexing model from the issue text.

Description

src/tools/java_resource_extractor/resource_extractor.py filters out well-known junk from java resources, but its exclusion lists miss a few things that AGP's default packaging rules strip, so they end up in the final APK:

  • .knm files (Kotlin/Native klib metadata)
  • .kotlin_metadata files
  • linkdata/ directories (e.g. commonMain/.../linkdata/*)
  • root-level LICENSE.txt / NOTICE.txt from library jars (the META-INF copies are already covered by the meta-inf directory exclusion)

The klib metadata is only consumed by the Kotlin compiler when compiling against a library; nothing reads it at runtime, so in an APK it's dead weight. In the Gradle world it's common to exclude it via packaging options on top of AGP's defaults. With a KMP-heavy dependency tree (kotlinx-*, androidx KMP artifacts) it adds up — on our app stripping all of the above saved ~0.45 MiB uncompressed (~0.24 MiB compressed).

This deliberately does not touch META-INF/*.kotlin_module, which kotlin-reflect needs at runtime.

Patch: https://github.com/Dolfik1/rules_android/commit/ead968493476d45059224949ec2536755b1a8aab

Happy to send this as a PR.

Dominant language
Java
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