Fixed race condition in PollingDeviceDiscovery. #145506
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christopherfujino
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LGTM, nice! How did you find this bug, btw?
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FYI @vashworth |
There are two issues in the previous implementation: 1. `_populateDevices` will return the devices from `deviceNotifier` if it had been initialized, assuming that once it's initialized, it has been properly populated. That assumption is not true because calling getters like `onAdded` would initialize `deviceNotifier` without populating it. 2. `deviceNotifier` instance might be replaced in some cases, causing `onAdded` subscribers to lose any future updates. To fix (1), this commit added the `isPopulated` field in `deviceNotifier` as a more accurate flag to determine if we need to populate it. To fix (2), this commit made `deviceNotifier` a final member in `PolingDeviceDiscovery`.
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We found it because the tool is failing inconsistently for some of us internally, with an error message saying "device not found". For me, the reproduction rate is maybe ~10%, for some people it's higher (not sure why). The weird thing that caught our attention is that, even though it claimed that device is not found, the report generated right after the failure still contains that specific device id. So we traced the call stack and found this bug as a possible explanation. After this fix, I can no longer reproduce the issue by launching the app a bunch of times. So hopefully this is the only race condition :) |
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flutter/flutter@18340ea...14774b9 2024-03-22 engine-flutter-autoroll@skia.org Roll Flutter Engine from eba6e31498b8 to 09dadce76828 (1 revision) (flutter/flutter#145603) 2024-03-22 engine-flutter-autoroll@skia.org Roll Flutter Engine from f9a34ae0b14f to eba6e31498b8 (1 revision) (flutter/flutter#145598) 2024-03-22 nate.w5687@gmail.com Intensive `if` chain refactoring (flutter/flutter#145194) 2024-03-22 leroux_bruno@yahoo.fr Adds numpad navigation shortcuts for Linux (flutter/flutter#145464) 2024-03-22 engine-flutter-autoroll@skia.org Roll Flutter Engine from 5a12de1beab7 to f9a34ae0b14f (1 revision) (flutter/flutter#145581) 2024-03-22 engine-flutter-autoroll@skia.org Roll Flutter Engine from e2f324beac3b to 5a12de1beab7 (1 revision) (flutter/flutter#145578) 2024-03-22 31859944+LongCatIsLooong@users.noreply.github.com Replace `RenderBox.compute*` with `RenderBox.get*` and add `@visibleForOverriding` (flutter/flutter#145503) 2024-03-22 gspencergoog@users.noreply.github.com Add some cross references in the docs, move an example to a dartpad example (flutter/flutter#145571) 2024-03-22 bernaferrari2@gmail.com Fix `BorderSide.none` requiring explicit transparent color for `UnderlineInputBorder` (flutter/flutter#145329) 2024-03-22 engine-flutter-autoroll@skia.org Roll Flutter Engine from a46a7b273a5b to e2f324beac3b (1 revision) (flutter/flutter#145576) 2024-03-21 goderbauer@google.com Fix nullability of getFullHeightForCaret (flutter/flutter#145554) 2024-03-21 34871572+gmackall@users.noreply.github.com Add a `--no-gradle-generation` mode to the `generate_gradle_lockfiles.dart` script (flutter/flutter#145568) 2024-03-21 engine-flutter-autoroll@skia.org Roll Flutter Engine from 1b842ae58b3d to a46a7b273a5b (2 revisions) (flutter/flutter#145569) 2024-03-21 chingjun@google.com Fixed race condition in PollingDeviceDiscovery. (flutter/flutter#145506) 2024-03-21 engine-flutter-autoroll@skia.org Roll Flutter Engine from a2ed373fa70f to 1b842ae58b3d (1 revision) (flutter/flutter#145565) 2024-03-21 ian@hixie.ch Clarify AutomaticKeepAliveClientMixin semantics in build method (flutter/flutter#145297) 2024-03-21 goderbauer@google.com Eliminate more window singleton usages (flutter/flutter#145560) 2024-03-21 jacksongardner@google.com `flutter test --wasm` support (flutter/flutter#145347) 2024-03-21 engine-flutter-autoroll@skia.org Roll Flutter Engine from eb262e9c34db to a2ed373fa70f (2 revisions) (flutter/flutter#145556) 2024-03-21 engine-flutter-autoroll@skia.org Roll Flutter Engine from bad4a30e1c75 to eb262e9c34db (1 revision) (flutter/flutter#145555) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-packages Please CC camillesimon@google.com,rmistry@google.com,stuartmorgan@google.com on the revert to ensure that a human is aware of the problem. To file a bug in Packages: 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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There are two issues in the previous implementation:
_populateDeviceswill return the devices fromdeviceNotifierif it had been initialized, assuming that once it's initialized, it has been properly populated. That assumption is not true because calling getters likeonAddedwould initializedeviceNotifierwithout populating it.deviceNotifierinstance might be replaced in some cases, causingonAddedsubscribers to lose any future updates.To fix (1), this commit added the
isPopulatedfield indeviceNotifieras a more accurate flag to determine if we need to populate it.To fix (2), this commit made
deviceNotifiera final member inPolingDeviceDiscovery.Pre-launch Checklist
///).If you need help, consider asking for advice on the #hackers-new channel on Discord.