[shared_preferences] Keep Kotlin classes used through JNI in Android release builds by ybeshkarov · Pull Request #13311 · flutter/packages

ybeshkarov · 2026-10-17T20:22:11Z

shared_preferences_android 2.5.0 calls its Kotlin code through JNI. The generated Dart bindings and package:jni look up some Kotlin standard library classes by name, but nothing keeps them, so R8 renames them in release builds. From mapping.txt of a release build with 2.5.0:

kotlin.Result -> l1.d:
kotlin.Result$Failure -> l1.c:
kotlin.Unit -> l1.g:
kotlin.coroutines.Continuation -> o1.d:
kotlin.coroutines.intrinsics.CoroutineSingletons -> p1.a:

The generated classes are kept by @Keep, but R8 rewrites their method descriptors with the renamed Continuation. So every call fails with a NoSuchMethodError, for example:

NoSuchMethodError: no non-static method "Lio/flutter/plugins/sharedpreferences/SharedPreferencesAsyncApiRegistrar;.getAll(Ljava/util/List;Lio/flutter/plugins/sharedpreferences/SharedPreferencesPigeonOptions;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;"

and SharedPreferences.getInstance(), SharedPreferencesAsync and SharedPreferencesWithCache.create() all throw. Debug and profile builds work.

This PR adds android/consumer-rules.pro with the six keep rules from Pigeon's native interop guide ("Step 5: Android Release Build Configuration (JNI)") and lists it in consumerProguardFiles, the same way packages/pigeon/platform_tests/test_plugin does. R8 then applies the rules to every app that uses the plugin. The six classes are the ones looked up by name: kotlin.coroutines.Continuation in the descriptors of the suspend methods and kotlin.Unit in messages*.g.dart, plus kotlin.Unit, kotlin.Result, kotlin.Result$Failure, kotlin.coroutines.Continuation, CoroutineSingletons and IntrinsicsKt in lib/src/kotlin.dart of jni 1.1.0. The other Kotlin types in the bindings (DefaultConstructorMarker, EnumEntries) only appear in synthetic constructors and getEntries, which the plugin never calls. A TODO in consumer-rules.pro and build.gradle.kts points to dart-lang/native#3732, so the rules can be removed once jni ships them.

Fixes flutter/flutter#194649

How I verified it: a fresh flutter create --platforms android app with shared_preferences: ^2.5.5 that calls SharedPreferencesWithCache.create() in main() and counts launches. I built it with flutter build apk --release --target-platform android-arm64 (Flutter 3.44.2, AGP 9.0.1, Gradle 9.1.0, R8 on by default) and ran it on an API 37 arm64 emulator.

With shared_preferences_android 2.5.0 from pub.dev, the app stays on the splash screen and logcat shows the NoSuchMethodError above from SharedPreferencesWithCache.create.
With a dependency_overrides path to this branch, configuration.txt of the build lists the rules from the plugin's consumer file, mapping.txt maps each class to itself (for example kotlin.coroutines.Continuation -> kotlin.coroutines.Continuation:), and the app starts. It logs launches=1, and launches=2 after a restart.
A second entry point that round-trips every value type, getKeys, getAll, remove and clear through SharedPreferencesAsync and the legacy SharedPreferences API fails for both APIs with 2.5.0 and passes for both with this branch.

I also ran flutter test in the package (39 tests pass) and validate --check-for-missing-changes, analyze, format, dart-test, publish-check and license-check of the repo tooling for the package. None of them reported an issue.

Test exemption: I'd like to request one. The change is build configuration that only affects R8 in an app's release build, and as far as I can tell no CI target runs a release build of a plugin. drive-examples, the native integration tests and Firebase Test Lab use debug builds, and android_build_all_packages builds the all_packages app in release but doesn't run it. If there is a place where a release-mode test would fit, I'm happy to add one.

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…builds shared_preferences_android 2.5.0 calls its Kotlin code through JNI. The generated Dart bindings and package:jni look up several Kotlin standard library classes by name, such as kotlin.coroutines.Continuation. R8 renames them in release builds, so every call fails with a NoSuchMethodError and SharedPreferences.getInstance() and SharedPreferencesWithCache.create() throw at startup. Adds consumer R8 rules that keep those classes, as Pigeon's native interop guide describes for plugins, until package:jni ships them (dart-lang/native#3732).

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flutter-dashboard · 2026-10-17T20:28:19Z

It looks like this pull request may not have tests. Please make sure to add tests or get an explicit test exemption before merging.

If you are not sure if you need tests, consider this rule of thumb: the purpose of a test is to make sure someone doesn't accidentally revert the fix. Ask yourself, is there anything in your PR that you feel it is important we not accidentally revert back to how it was before your fix?

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing. If both you and the PR author believe this PR qualifies for a test exemption, escalate to the tech lead for the changed area to review and apply the test-exempt label. All reviewers should feel empowered to ask for tests before escalating.

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Code Review

This pull request updates the shared_preferences_android package to version 2.5.1. It introduces a consumer-rules.pro file with Proguard/R8 keep rules for specific Kotlin classes, including kotlin.Unit, kotlin.Result, and coroutine-related classes, to prevent them from being stripped or renamed in release builds. It also configures build.gradle.kts to apply these consumer Proguard files, and updates pubspec.yaml and CHANGELOG.md accordingly. There are no review comments, and I have no feedback to provide.

…n integrated into the package yet (flutter/packages#13311). Without this patch, the R8 obfuscates methods and the app throws "NoSuchMethod" errors on startup which hang the app because the calls are awaited (even if it did bypass the wait, the shared preferences wouldn't work correctly anyway).

… JNI Kotlin classes, verifier refuses renamed ones alpha.125's pub wave took shared_preferences_android to 2.5.0, whose Pigeon JNI bindings resolve kotlin.coroutines.Continuation/Unit/Result by name. R8 renamed them in the release APK, the first prefs read before runApp threw NoSuchMethodError, and the app never left the Android splash. - pubspec: shared_preferences_android '>=2.4.28 <2.5.0' (pre-JNI impl) - android/app/proguard-rules.pro keeps the six JNI-resolved classes - verify_android_apk.py: inspect_dex_keeps refuses an APK where any of the three was renamed (+3 tests); receipt gains kept_jni_classes - CLAUDE.md: root cause + verification record Upstream: flutter/flutter#194649, flutter/packages#13311. Co-Authored-By: Claude Fable 5.1 <[email protected]>

…in-keep-rules # Conflicts: # packages/shared_preferences/shared_preferences_android/CHANGELOG.md

mboetger

LGTM aside from todo update

tarrinneal

Thank you for throwing this together so quickly

auto-submit · 2026-10-20T18:45:56Z

autosubmit label was removed for flutter/packages/13311, because - This pull request has the missing-tests label and does not have the test-exempt label. Please add tests or obtain a test exemption from a tech lead before re-applying the autosubmit label.

ybeshkarov · 2026-10-20T18:50:04Z

@tarrinneal, @mboetger thanks for the approval! Looks like the bot pulled autosubmit over missing-tests. Could you ask a tech lead for test-exempt? The reasoning is in the description: the rules only matter in release builds, and CI never runs a plugin in release. If you'd rather have a test, just point me to a spot and I'll add one.

ybeshkarov · 2026-10-21T02:18:16Z

@tarrinneal @mboetger thanks for merging! The release run for the merge commit failed at "Wait for test check-in", since the LUCI check it waits for didn't show up within 60 seconds (https://github.com/flutter/packages/actions/runs/39526055358). So 2.5.2 isn't on pub.dev yet. Could one of you re-run it once post-submit has run?

flutter/packages@618afba...1383427 2026-10-21 [email protected] [shared_preferences] Keep Kotlin classes used through JNI in Android release builds (flutter/packages#13311) 2026-10-20 [email protected] [webview_flutter_wkwebview] Roll back iOS and macOS versions (flutter/packages#13354) 2026-10-20 [email protected] [camera]fix resolution test failure due to hardware restriction (flutter/packages#13356) 2026-10-20 [email protected] [google_maps_flutter_web] Fail fast and deduplicate map setup in integration tests (flutter/packages#13092) 2026-10-20 [email protected] [camera_avfoundation] Fix Swift analyzer issues in tests (flutter/packages#13340) 2026-10-20 [email protected] Sync release-material_ui-1.8.0 to main (flutter/packages#13346) 2026-10-20 [email protected] [material_ui] add a `barFocusNode` to `SearchAnchor.bar` (ref: flutter#186073) (flutter/packages#12863) 2026-10-20 [email protected] [in_app_purchase_storekit] Expose sk2Transaction on SK2PurchaseDetails (flutter/packages#13341) 2026-10-20 [email protected] Sync release-cupertino_ui-1.1.4 to main (flutter/packages#13350) 2026-10-20 [email protected] [google_maps_flutter_web] Don't hang `onMapCreated` when tiles fail to load (flutter/packages#13059) 2026-10-20 [email protected] [material_ui] Unskip web tests that pass on CanvasKit and Skwasm: adaptive_text_selection_toolbar_test, material_button_test, outlined_button_test, text_button_test (flutter/packages#13335) 2026-10-20 [email protected] Sync release-go_router-18.1.1 to main (flutter/packages#13347) 2026-10-20 [email protected] [camera] Add zero-shutter-lag support to camera_android_camerax and camera_avfoundation (flutter/packages#13199) If this roll has caused a breakage, revert this CL and set the roller to dry run mode using the controls here: https://autoroll.skia.org/r/flutter-packages-flutter-autoroll Please CC [email protected] on the revert to ensure that a human is aware of the problem. To file a bug in Flutter: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

2.5.0 (resolved into the lockfile on 2026-10-17) moved to Pigeon JNI interop, and R8 renames the kotlin.coroutines classes it calls, so SharedPreferences.getInstance() in main() throws NoSuchMethodError before runApp() ever renders — the release APK hangs on the splash screen while debug builds work (flutter/flutter#194649, upstream fix flutter/packages#13311). Pin until a fixed version ships, then drop the constraint. The jni FFI plugin leaves the generated plugin lists with the older version.

flutter/packages@618afba...1383427 2026-10-21 [email protected] [shared_preferences] Keep Kotlin classes used through JNI in Android release builds (flutter/packages#13311) 2026-10-20 [email protected] [webview_flutter_wkwebview] Roll back iOS and macOS versions (flutter/packages#13354) 2026-10-20 [email protected] [camera]fix resolution test failure due to hardware restriction (flutter/packages#13356) 2026-10-20 [email protected] [google_maps_flutter_web] Fail fast and deduplicate map setup in integration tests (flutter/packages#13092) 2026-10-20 [email protected] [camera_avfoundation] Fix Swift analyzer issues in tests (flutter/packages#13340) 2026-10-20 [email protected] Sync release-material_ui-1.8.0 to main (flutter/packages#13346) 2026-10-20 [email protected] [material_ui] add a `barFocusNode` to `SearchAnchor.bar` (ref: flutter#186073) (flutter/packages#12863) 2026-10-20 [email protected] [in_app_purchase_storekit] Expose sk2Transaction on SK2PurchaseDetails (flutter/packages#13341) 2026-10-20 [email protected] Sync release-cupertino_ui-1.1.4 to main (flutter/packages#13350) 2026-10-20 [email protected] [google_maps_flutter_web] Don't hang `onMapCreated` when tiles fail to load (flutter/packages#13059) 2026-10-20 [email protected] [material_ui] Unskip web tests that pass on CanvasKit and Skwasm: adaptive_text_selection_toolbar_test, material_button_test, outlined_button_test, text_button_test (flutter/packages#13335) 2026-10-20 [email protected] Sync release-go_router-18.1.1 to main (flutter/packages#13347) 2026-10-20 [email protected] [camera] Add zero-shutter-lag support to camera_android_camerax and camera_avfoundation (flutter/packages#13199) If this roll has caused a breakage, revert this CL and set the roller to dry run mode using the controls here: https://autoroll.skia.org/r/flutter-packages-flutter-autoroll Please CC [email protected] on the revert to ensure that a human is aware of the problem. To file a bug in Flutter: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

flutter-dashboard Bot added the missing-tests label Oct 17, 2026

github-actions Bot added platform-android p: shared_preferences labels Oct 17, 2026

ybeshkarov marked this pull request as ready for review October 17, 2026 20:28

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ybeshkarov mentioned this pull request Oct 19, 2026

[shared_preferences] shared_preferences_android 2.5.0 crashes release builds at start: NoSuchMethodError in SharedPreferencesAsyncApiRegistrar.getAll (R8) flutter/flutter#194649

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LinXunFeng mentioned this pull request Oct 19, 2026

[jni] Preserve Kotlin runtime classes used by suspend calls in Android release builds dart-lang/native#3747

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Merge remote-tracking branch 'upstream/main' into fix-release-r8-kotl…

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…in-keep-rules # Conflicts: # packages/shared_preferences/shared_preferences_android/CHANGELOG.md

ybeshkarov mentioned this pull request Oct 20, 2026

[shared_preferences] configure consumer rules to fix R8 breakage #13343

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mboetger requested changes Oct 20, 2026

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Comment thread packages/shared_preferences/shared_preferences_android/android/build.gradle.kts Resolved

mboetger requested a review from camsim99 October 20, 2026 16:59

Point the TODOs at the jni issue instead of a person

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ybeshkarov requested a review from mboetger October 20, 2026 18:07

mboetger approved these changes Oct 20, 2026

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Merge branch 'main' into fix-release-r8-kotlin-keep-rules

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tarrinneal added the autosubmit Merge PR when tree becomes green via auto submit App label Oct 20, 2026

auto-submit Bot removed the autosubmit Merge PR when tree becomes green via auto submit App label Oct 20, 2026

mboetger added test-exempt Exempt from tests. Overrides `missing-tests` label autosubmit Merge PR when tree becomes green via auto submit App labels Oct 20, 2026

auto-submit Bot merged commit 1383427 into flutter:main Oct 21, 2026
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saurabh-mirajkar mentioned this pull request Oct 21, 2026

await SharedPreferences.getInstance() blocks the app flutter/flutter#194879

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engine-flutter-autoroll mentioned this pull request Oct 21, 2026

Roll Packages from 618afba31419 to 138342751909 (13 revisions) flutter/flutter#194956

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ybeshkarov deleted the fix-release-r8-kotlin-keep-rules branch October 22, 2026 14:32

ybeshkarov mentioned this pull request Oct 22, 2026

fix(shared_preferences): allow shared_preferences_android 2.5.2, which keeps the Kotlin classes that release builds need saymyframe/smf_flutter_cli#252

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amake mentioned this pull request Oct 26, 2026

2.7.0 Android doesn't launch correctly amake/orgro#223

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tarrinneal mentioned this pull request Oct 30, 2026

[shared_preferences] Update shared_preferences_android and shared_preferences_foundation to Pigeon 29.0.13 and jni 1.1.1 #13497

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swaiku mentioned this pull request Nov 4, 2026

🐛 Fix release builds hanging at startup swaiku/pigeon-finder#29

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Akhrameev mentioned this pull request Nov 13, 2026

[url_launcher] Migrate android/ios to Pigeon native interop #13642

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[shared_preferences] Keep Kotlin classes used through JNI in Android release builds - #13311

[shared_preferences] Keep Kotlin classes used through JNI in Android release builds#13311
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