waylnd: [FATAL:flutter/shell/common/display_manager.cc(32)] Check failed: displays_.empty().

[angelobt]

we are using weston compositor with kiosk shell.

We have a flutter application using flutter-wayland-client.

updating from 05b0377d52662a33d53370f745e2f127d4ec0248 to head (1 sept 2023) we run into this error

[FATAL:flutter/shell/common/displaymanager.cc(32)] Check failed: displays.empty().

that happens if an other application (like gstreamer) wants to render something through wayland.

[HidenoriMatsubayashi]

I feel https://github.com/sony/flutter-embedded-linux/pull/374 is probably the cause.

[HidenoriMatsubayashi]

that happens if an other application (like gstreamer) wants to render something through wayland.

Specifically, can you please tell me how to reproduce this issue?

[HidenoriMatsubayashi]

This issue shouldn't occur in release flavor.

https://github.com/flutter/engine/blob/main/shell/common/display_manager.cc#L27C15-L27C23

void DisplayManager::HandleDisplayUpdates(
    std::vector<std::unique_ptr<Display>> displays) {
  FML_DCHECK(!displays.empty());
  std::scoped_lock lock(displays_mutex_);
  displays_ = std::move(displays);
}

[angelobt]

Thanks for the support. As soon as possible we will try the release flavor

[HidenoriMatsubayashi]

This failure is really strange. It can't happen as I've implemented UpdateDiplayInfo API call with display_count = 1.

https://github.com/sony/flutter-embedded-linux/blob/master/src/flutter/shell/platform/linux_embedded/flutter_elinux_view.cc#L578:

void FlutterELinuxView::UpdateDisplayInfo(double refresh_rate,
                                          size_t width_px,
                                          size_t height_px,
                                          double pixel_ratio) {
  const FlutterEngineDisplaysUpdateType update_type =
      kFlutterEngineDisplaysUpdateTypeStartup;
  const FlutterEngineDisplay displays = {
      .struct_size = sizeof(FlutterEngineDisplay),
      .display_id = 0,
      .single_display = true,
      .refresh_rate = refresh_rate,
      .width = width_px,
      .height = height_px,
      .device_pixel_ratio = pixel_ratio,
  };
  const size_t display_count = 1;
  engine_.get()->UpdateDisplayInfo(update_type, &displays, display_count);
}

[FATAL:flutter/shell/common/displaymanager.cc(32)] Check failed: displays.empty().

Also, this error shows the line number is 32, but it should be line 27. https://github.com/flutter/engine/blob/main/shell/common/display_manager.cc#L27C15-L27C23

@angelobt What flutter/engine version are you using? Also, are you using this software (flutter-embedded-linux) as is?

[omarhogni]

+1 for this issue, same setup weston, kiosk shell

[HidenoriMatsubayashi]

Can you please share the detailed steps to reproduce this crash?

[omarhogni]

Switching to 7f83ccb9a9790ab31758e76b3b5498be2af32af7 it looks like the error is gone.

[omarhogni]

For me this is not a crash but just at startup. But I am consuming this project through meta-flutter and using that project to build the engine and do the heavy lifting. then I just start it.

What kind of steps are you looking for?

[HidenoriMatsubayashi]

What version of flutter/engine are you using?

What kind of steps are you looking for?

Just how to reproduce this issue / your steps. I have never used weston + kiosk shell. Also, can this issue be reproduced on desktop PCs?

[HidenoriMatsubayashi]

Just in case, FlutterEngineDisplay API of flutter/engine's embedder has been supported since flutter 3.13.0. If you use the latest this software, you need to use flutter version 3.13.0 or higher.

[omarhogni]

I am using 3.7.7 so that might be it.

[HidenoriMatsubayashi]

Definitely, yes. Please use 3.13.0 or higher. I'll close this issue. Please let me know if you get this error even if you use the correct versions. I'll re-open it.

[angelobt]

I'm using flutter-engine 3.3.10. So it makes sense