perf(android): APK size reduction phase 1

[priyavratuniyal]

Summary

• Split release APK per ABI (arm64 + x64 only), eliminating the 287 MB universal fat build
• Enable R8 minification and resource shrinking for release builds
• Exclude Vulkan debug validation layer (15 MB) from release packaging
• Exclude unused MediaPipe image generation libs (24 MB) from release packaging

Results

APK	Before	After
Universal (all ABIs)	287 MB	—
arm64-v8a	—	150.1 MB
x86_64	—	93.3 MB

Further reduction to ~35–45 MB requires replacing flutter_gemma with llama_cpp_dart (phase 2).

Test plan

• Release build on a real arm64 device
• PDF import and parsing works
• Chat / LLM inference works
• Biomarker dashboard renders correctly

Summary by CodeRabbit

Release Notes

Chores

• Optimized release builds to produce architecture-specific APKs for improved compatibility and reduced download sizes.
• Enabled code minification and resource shrinking to minimize overall app size.
• Streamlined native library packaging for more efficient builds.

[coderabbitai]

📝 Walkthrough

Walkthrough

The release build process has been updated to generate ABI-specific APKs for ARM64 and x64 architectures rather than a single universal APK. Additionally, code minification and resource shrinking have been enabled in the Android release build configuration, with specific native libraries excluded from packaging.

Changes

Cohort / File(s)	Summary
Release Workflow .github/workflows/release.yml	Modified flutter build apk command to generate ABI-split APKs using --split-per-abi flag; updated artifact renaming and GitHub Release upload to handle multiple ABI-specific APK files via glob patterns.
Android Build Configuration android/app/build.gradle.kts	Enabled code minification (isMinifyEnabled = true) and resource shrinking (isShrinkResources = true) for release builds; added packaging block to exclude specific native shared libraries (libVkLayer_khronos_validation.so, libmediapipe_tasks_vision_image_generator_jni.so, libimagegenerator_gpu.so) from bundling.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Poem

🐰 The APKs split with purpose and care,
Each platform gets its own perfect pair,
Code shrinks down, libraries fade away,
Release builds are swifter today! ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'perf(android): APK size reduction phase 1' accurately describes the main change—reducing Android APK size through ABI splitting, minification, resource shrinking, and exclusion of debug/unused libraries.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feature/apk-size-reduction

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[coderabbitai]

🧹 Nitpick comments (1)

.github/workflows/release.yml (1)

40-45: Consider adding error handling for the APK rename loop.

If the build fails silently or produces unexpected output, the glob app-*-release.apk won't match any files, and bash will iterate with the literal string, causing a confusing mv error.

🛠️ Suggested improvement with error handling

       - name: Rename APKs with version
         run: |
           cd build/app/outputs/flutter-apk
+          shopt -s nullglob
+          apks=(app-*-release.apk)
+          if [ ${`#apks`[@]} -eq 0 ]; then
+            echo "Error: No APKs found matching app-*-release.apk"
+            exit 1
+          fi
           for apk in app-*-release.apk; do
             mv "$apk" "koshika-${{ github.ref_name }}-${apk#app-}"
           done

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In @.github/workflows/release.yml around lines 40 - 45, The rename loop can run
with the literal glob when no APKs exist; modify the step so you first expand
the pattern into an array (files=(app-*-release.apk)) or enable nullglob (shopt
-s nullglob) and then check if the array is empty before the for loop; if empty,
emit an error message and exit non-zero, otherwise iterate over the array (for
apk in "${files[@]}") and run mv "koshika-${{ github.ref_name }}-${apk#app-}"
only for real files to avoid spurious mv errors.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In @.github/workflows/release.yml:
- Around line 40-45: The rename loop can run with the literal glob when no APKs
exist; modify the step so you first expand the pattern into an array
(files=(app-*-release.apk)) or enable nullglob (shopt -s nullglob) and then
check if the array is empty before the for loop; if empty, emit an error message
and exit non-zero, otherwise iterate over the array (for apk in "${files[@]}")
and run mv "koshika-${{ github.ref_name }}-${apk#app-}" only for real files to
avoid spurious mv errors.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: a1696475-d27d-4f8b-8039-55bdb048f148

📥 Commits

Reviewing files that changed from the base of the PR and between 6f533bc and 6b35f5a.

📒 Files selected for processing (2)

• .github/workflows/release.yml
• android/app/build.gradle.kts