[Karataso]

What

Fixes the native crash that closes the app silently when sending the first message of a
Local Platform chat in any release build (F-Droid / Play).

Two files:

1. app/proguard-rules.pro — the fix

# LiteRT-LM (on-device inference)
# The litertlm-android AAR ships no consumer ProGuard rules, but its native layer
# resolves Java members by name through JNI. LiteRtLmJni.nativeCreateConversation
# calls SamplerConfig.getTopK()/getTopP()/getTemperature() via CallIntMethod, and
# the streaming path calls MessageCallback.onMessage/onDone/onError. R8 full mode
# strips these members because nothing in Java references them, GetMethodID
# returns null, and ART aborts the process with
# "JNI DETECTED ERROR IN APPLICATION: mid == null" on the first local message.
# Keeping the package also preserves the names of this app's MessageCallback and
# OpenApiTool implementations, which must match the interfaces they override.
-keep class com.google.ai.edge.litertlm.** { *; }

2. LiteRtLmAdapter.kt — defensive hardening

catch (error: Exception) → catch (error: Throwable) in three places (streamRound,
loadEngineOrFallback, and its inner CPU-fallback catch), with CancellationException
rethrown first. LiteRT-LM can surface Errors (UnsatisfiedLinkError,
OutOfMemoryError) that Exception handlers never see; those currently escape the adapter
and kill the process instead of producing an in-chat error.

This is not what caused the reported SIGABRT (a native signal cannot be caught from
Kotlin), it just closes the same class of "app dies with no message" failures.

Why

Crash report:

signal 6 (SIGABRT)
Abort message: 'JNI DETECTED ERROR IN APPLICATION: mid == null
    in call to CallIntMethodV
    from long com.google.ai.edge.litertlm.LiteRtLmJni.nativeCreateConversation(...)'

JNI-resolved member	in liblitertlm_jni.so	in shipped classes.dex
getTopK / getTopP / getTemperature	yes	no
onMessage / onDone / onError	yes	no
litertlm/SamplerConfig (class)	—	yes (kept by the native method descriptor)

litertlm-android-0.11.0.aar ships no proguard.txt, so nothing tells R8 that these members
are referenced from native code. Debug builds never reproduce it because they are not minified.

Testing

• ./gradlew assembleRelease, confirm getTopK and onMessage are present in the
  release classes.dex (they were absent before the rule).
• Install the release build on device, download a local model, send the first message.
• Confirm the reply streams and the app survives multi-turn chat.
• ./gradlew test / ktlint unchanged (no Kotlin source touched except LiteRtLmAdapter).

Summary by CodeRabbit

• Bug Fixes
  • Improved compatibility of local inference in optimized app builds, preventing required model-integration methods from being removed.
  • Engine loading still falls back to CPU when loading with a requested accelerator fails, and reports an error if CPU loading also fails. Fatal system-level errors are no longer handled as recoverable failures.

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Reviewing files that changed from the base of the PR and between ff55d7e and ed53cb8.

📒 Files selected for processing (1)

• app/src/main/kotlin/dev/chungjungsoo/gptmobile/data/agent/provider/LiteRtLmAdapter.kt

🚧 Files skipped from review as they are similar to previous changes (1)

• app/src/main/kotlin/dev/chungjungsoo/gptmobile/data/agent/provider/LiteRtLmAdapter.kt

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📝 Walkthrough

Walkthrough

The changes add a ProGuard keep rule for LiteRT-LM classes and broaden failure handling in LiteRtLmAdapter for inference and engine loads. Existing cancellation handling remains in place.

Changes

LiteRT-LM integration

Layer / File(s)	Summary
Preserve LiteRT-LM classes app/proguard-rules.pro	Adds a keep rule for the com.google.ai.edge.litertlm.** package. Comments describe JNI methods resolved by name and the app implementations that the rule preserves.
Handle inference and engine-load failures app/src/main/kotlin/dev/chungjungsoo/gptmobile/data/agent/provider/LiteRtLmAdapter.kt	streamRound catches Throwable for otherwise-unhandled failures. Requested-engine and CPU-fallback loads also catch Throwable; cancellation remains rethrown. Existing failure handling remains in place.

Priority: ➖ Normal

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

Suggested reviewers: taewan-p

Merge Risk: ⚪ Minimal · up to ed53c

No actionable merge-blocking issue was found. The planned release-build and device checks remain to be completed.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 3 functions across 1 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the primary change: preserving LiteRT-LM members so local inference works in release builds.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

• Fix all pre-merge checks with AI

✨ Finishing Touches 💡 1

🛠️ Fix failing CI checks 💡

• Commit to this branch
• Create a new PR

🧪 Generate unit tests (beta)

• Create a new PR

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Actionable comments posted: 1

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• 🪄 Fix CodeRabbit comments on this PR

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Inline comments:
In
`@app/src/main/kotlin/dev/chungjungsoo/gptmobile/data/agent/provider/LiteRtLmAdapter.kt`:
- Line 247: Update all three Throwable handlers in the LiteRT-LM adapter,
including the handler around loadEngine(requested), to rethrow
VirtualMachineError and ThreadDeath before applying existing recovery or failure
handling. Preserve the current handling for recoverable LiteRT-LM errors.

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Reviewing files that changed from the base of the PR and between 9808262 and ff55d7e.

📒 Files selected for processing (2)

• app/proguard-rules.pro
• app/src/main/kotlin/dev/chungjungsoo/gptmobile/data/agent/provider/LiteRtLmAdapter.kt

Included review availability: Your plan provides up to 4 included reviews per hour; 3 remain after this review.

[Karataso]

Note on the failing Build debug APK check

It fails for a reason unrelated to this PR:

##[error] Refusing to check out fork pull request code from a 'pull_request_target' workflow.

.github/workflows/debug-build.yml triggers on pull_request_target while actions/checkout@v6 is pointed at the fork's ref and repo:

on:
  pull_request_target:
...
      - uses: actions/checkout@v6
        with:
          ref: ${{ github.event.pull_request.head.ref }}
          repository: ${{ github.event.pull_request.head.repo.full_name }}

checkout refuses that by default (https://gh.io/securely-using-pull_request_target), so every PR from a fork hits it — same-repo branches are unaffected. This job only runs ./gradlew assembleDebug and posts an artifact link, and the workflow already ignores .github/**, so switching the trigger to plain pull_request should make it work for external contributors.

The other three checks (Kotlin Lint Check, CodeQL Advanced, Pull request validation) are action_required, i.e. waiting for maintainer approval for a first-time contributor — that part is expected.

Validation done locally on this revision

• ./gradlew assembleDebug — OK
• ./gradlew assembleRelease + apksigner — OK, and getTopK, getTopP, getTemperature, onMessage, onDone, onError are now present in the release classes.dex (all absent before the keep rules)
• ktlint 1.3.1 (android_studio style) over app/src/main/kotlin — 0 findings
• Device: Pixel 7 Pro / Android 16 — the release build loads DeepSeek-R1-Distill-Qwen-1.5B and streams replies with an empty crash buffer, where F-Droid 0.9.0 aborted with JNI DETECTED ERROR: mid == null on every attempt

Reported the root cause upstream as well: google-ai-edge/LiteRT-LM#3739

[Taewan-P]

@codex review

[Taewan-P]

LGTM! Thanks for the contribution 👍