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[shared_preferences] Defer SharedPreferences fetch in LegacySharedPreferencesPlugin until first use on Android - #13431
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This pull request defers the initialization of SharedPreferences in LegacySharedPreferencesPlugin until its first use to avoid main-thread disk I/O during plugin registration, and adds a corresponding unit test to verify this behavior. Feedback suggests using Kotlin's idiomatic by lazy delegate for thread-safe lazy initialization instead of manual double-checked locking.
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…gacySharedPreferencesPlugin` executing synchronous disk I/O on Android main thread during startup Fixes eager SharedPreferences fetch in `LegacySharedPreferencesPlugin` executing synchronous disk I/O on Android main thread during startup by deferring the fetch until first use. Fixes flutter/flutter#195313
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flutter/packages@23a05b6...a8549ae 2026-10-27 [email protected] [material_ui] Deprecate the black/white parameters in `Typography.material2021` (flutter/packages#13443) 2026-10-27 [email protected] [shared_preferences] Defer SharedPreferences fetch in `LegacySharedPreferencesPlugin` until first use on Android (flutter/packages#13431) 2026-10-27 [email protected] [material_ui] Fix MenuAnchor non-Unicode shortcut labels on JS web (flutter/packages#13370) 2026-10-27 [email protected] [material_ui] Add Checkbox.markInsets (flutter/packages#12690) 2026-10-27 [email protected] [vector_graphics_compiler] Handle coordinate lists on text and tspan (flutter/packages#13287) 2026-10-27 [email protected] [cupertino_ui] Unskip web tests that pass on CanvasKit and Skwasm: nav_bar_transition_test, refresh_test, route_test, text_field_cursor_test (flutter/packages#13439) 2026-10-27 [email protected] [material_ui] Fix `TextTheme` and `Typography` `debugFillProperties` defaults (flutter/packages#13374) 2026-10-27 [email protected] [material_ui] Update out-of-date typography documentation (flutter/packages#13372) 2026-10-27 [email protected] [shared_preferences_foundation] Fix web compilation of apps that import the package (flutter/packages#13447) 2026-10-26 [email protected] Fix AI guidelines link in PR template (flutter/packages#13411) 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
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flutter/packages@23a05b6...a8549ae 2026-10-27 [email protected] [material_ui] Deprecate the black/white parameters in `Typography.material2021` (flutter/packages#13443) 2026-10-27 [email protected] [shared_preferences] Defer SharedPreferences fetch in `LegacySharedPreferencesPlugin` until first use on Android (flutter/packages#13431) 2026-10-27 [email protected] [material_ui] Fix MenuAnchor non-Unicode shortcut labels on JS web (flutter/packages#13370) 2026-10-27 [email protected] [material_ui] Add Checkbox.markInsets (flutter/packages#12690) 2026-10-27 [email protected] [vector_graphics_compiler] Handle coordinate lists on text and tspan (flutter/packages#13287) 2026-10-27 [email protected] [cupertino_ui] Unskip web tests that pass on CanvasKit and Skwasm: nav_bar_transition_test, refresh_test, route_test, text_field_cursor_test (flutter/packages#13439) 2026-10-27 [email protected] [material_ui] Fix `TextTheme` and `Typography` `debugFillProperties` defaults (flutter/packages#13374) 2026-10-27 [email protected] [material_ui] Update out-of-date typography documentation (flutter/packages#13372) 2026-10-27 [email protected] [shared_preferences_foundation] Fix web compilation of apps that import the package (flutter/packages#13447) 2026-10-26 [email protected] Fix AI guidelines link in PR template (flutter/packages#13411) 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
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Defers
getSharedPreferencesinLegacySharedPreferencesPluginout ofonAttachedToEngineuntil first use, avoiding synchronous disk I/O on the Android main thread during startup.The following screenshot shows that the time taken for
RegisterFlutterPluginsignificantly decreases with the change, which validates the fix:I also previously implemented this in my app, which was later negated by an upgrade of the shared_preferences packages into g3 and caused cold startup latency regression alerts on my app. Hoping to upstream the fix to get this optimization to all Flutter users.
flutter/flutter#195313 will be fixed by this PR.
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