[Crashlytics] com.google.mlkit:face-detection@@16.1.7 - com.google.mlkit.vision.face.bundled.internal.ThickFaceDetectorCreator.<clinit> #195

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1. stozo04

   added

   bugSomething isn't workingSomething isn't working

   crashlytics-auto

   on Sep 13, 2026
2. claude commented on Sep 13, 2026

   

   claudebot

   on Sep 13, 2026 – with Claude

   More actions

   Root-cause analysis

   MCP note: crashlytics_list_events returned an empty array (no sample events retrieved under this workflow's service-account auth — see issue #107). Triage is based on the issue metadata, the stacktrace in the title/subtitle, docs/lessons_learned/, and the source code.

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   Failing frame

   com.google.mlkit.vision.face.bundled.internal.ThickFaceDetectorCreator.<clinit>
   java.lang.UnsatisfiedLinkError: dlopen failed: library "libface_detector_v2_jni.so" not found
   

   Root cause

   FaceTracker initializes the ML Kit face detector at field-init time with no error handling.

   // camera/lens/FaceTracker.kt:50
   private val detector = FaceDetection.getClient(
       FaceDetectorOptions.Builder()…
   )

   When this field is initialized, ML Kit's ThickFaceDetectorCreator.<clinit> (the bundled model's static initializer) calls System.loadLibrary("face_detector_v2_jni"). On affected devices, dlopen cannot find libface_detector_v2_jni.so — most likely because that device's ABI is not covered by the bundled ML Kit 16.1.7 AAR, or the library fails 16 KB page-alignment mapping on an Android 15 device with 16 KB page size. The resulting UnsatisfiedLinkError propagates uncaught as ExceptionInInitializerError → fatal crash.

   Files involved

   • app/src/main/java/io/github/stozo04/openloop/camera/lens/FaceTracker.kt — missing LinkageError guard
   • app/src/main/java/io/github/stozo04/openloop/diagnostics/ReverseCrashlytics.kt — needs reportFaceTrackerUnavailable()

   Lesson 040 precedent

   HandTracker had the identical failure mode (MediaPipe's libmediapipe_tasks_jni.so absent / static initializer crash under R8), documented in docs/lessons_learned/040-run-the-release-apk-when-a-native-dependency-lands.md. The fix there: wrap tracker creation in try/catch (error: LinkageError), set a broken flag, report a non-fatal to Crashlytics, and degrade gracefully (camera still works, face lenses show pass-through).

   FaceTracker was introduced alongside HandTracker but was never given the same resilience.

   Fix

   1. Move FaceDetection.getClient() from a field initializer into an init {} block with try/catch (error: LinkageError).
   2. On failure: set broken = true, log, report non-fatal via ReverseCrashlytics.reportFaceTrackerUnavailable().
   3. analyze() bails early when broken — camera and other lenses continue working.
   4. Add reportFaceTrackerUnavailable() to ReverseCrashlytics.

   Confidence: HIGH — the same crash shape, the same library load path, the same missing guard, and an existing pattern in the codebase to follow. A draft PR with the minimal fix follows.
3. stozo04

   closed this as completedin #196on Sep 17, 2026
4. stozo04

   added a commit that references this issue on Sep 17, 2026

   fix(lens): survive a missing ML Kit face-detection native library

   ...

   This issue will close once commit 4c2b20a is merged into the 'main' branch.

   4c2b20a