example exits without any error

[rezaxdi]

Hi everyone,

I can build the example successfully on ubuntu 18.04 but when I try to run it just exits immediately without any error. Has anyone faced the same situation ?

[CallumIddon]

Yes, I am currently investigating this issue. What is the hash of your Flutter clone?

[stuartmorgan-g]

The GLFW implementation has some error paths that didn't end up with any logging, so it could be a failure there (e.g., GLFW window creation). A good starting point in debugging would be to add logging to the early returns in the example embedder and the GLFW embedder.cc (which I won't be able to get to myself for a couple of days, but would be happy to take a PR for).

[CallumIddon]

That's what I was thinking of doing, just haven't gotten around to it yet. I know it has something to do with the Flutter clone as I experience this problem only some channels and not others.

[HazyFish]

Same problem on Windows 10
The program '[20168] GLFW Example.exe' has exited with code 1 (0x1).

[soyflourbread]

Can be produced in Arch Linux.

In line 75 of https://github.com/google/flutter-desktop-embedding/blob/master/example/linux/flutter_embedder_example.cc#L75 , the GLFW window created is nullptr, and the code exited with error code 1.

[stuartmorgan-g]

For anyone seeing this, please provide:

• The hash of your Flutter tree.
• Whether you've previously had the example working on your machine.

[stuartmorgan-g]

In line 75 of https://github.com/google/flutter-desktop-embedding/blob/master/example/linux/flutter_embedder_example.cc#L75 , the GLFW window created is nullptr, and the code exited with error code 1.

In CreateFlutterWindow, is the null return coming from glfwCreateWindow, or RunFlutterEngine (I would guess the latter given CallumIddon's comment above). If the latter, what is the result in the FlutterEngineRun error handling?

[soyflourbread]

Well, flutter engine.version is 7375a0f414bde4bc941e623482221db2fc8c4ab5.
flutter-desktop-embedding commit is 1d90f97.
I can confirm commit f490eb6 is working.

[HazyFish]

window is a null pointer
engine.version: 7375a0f414bde4bc941e623482221db2fc8c4ab5

[soyflourbread]

In line 75 of https://github.com/google/flutter-desktop-embedding/blob/master/example/linux/flutter_embedder_example.cc#L75 , the GLFW window created is nullptr, and the code exited with error code 1.

In CreateFlutterWindow, is the null return coming from glfwCreateWindow, or RunFlutterEngine (I would guess the latter given CallumIddon's comment above). If the latter, what is the result in the FlutterEngineRun error handling?

It's from flutter_desktop_embedding::CreateFlutterWindowInSnapshotMode, the code exited at line 79.

[stuartmorgan-g]

flutter-desktop-embedding commit is 1d90f97.
I can confirm commit f490eb6 is working.

Ah, if this is a regression due to FDE changes, then 3089a8b is almost certainly the culprit in that range.

It's from flutter_desktop_embedding::CreateFlutterWindowInSnapshotMode, the code exited at line 79.

1d90f97 doesn't have CreateFlutterWindowInSnapshotMode, since it was renamed in 3089a8b. I've occasionally seen stale library issues with both Linux (Make, not GN) and Windows, that haven't been tracked down yet, so if everyone seeing this previously had working builds it may just be that something isn't being rebuilt.

Does doing a clean build (specifically, deleting all .sos from the tree on Linux--make clean may or may not get everything, since it hasn't been audited in a while) fix it?

[CallumIddon]

I've occasionally seen stale library issues with both Linux (Make, not GN) and Windows, that haven't been tracked down yet, so if everyone seeing this previously had working builds it may just be that something isn't being rebuilt.

I can confirm this happens with both GN and Make and on a fresh clone. I will get back to you tomorrow with a list of Flutter trees that I can confirm work.

[CallumIddon]

All of these tests were done on Ubuntu 18.04.1 with a fresh clone of Flutter and FDE, using commit f26ec2e and built using Make (ninja behaved the same when I was playing around with it earlier). This issue is a side effect of 3089a8b and everything before this commit works fine.

Flutter Hash	Flutter Branch	Build Successful	Run Successful
2eee7b7e942f57cb76075bed5fda8e1a619e5295	master	Yes	Yes
1407091bfb5bb535630d4d596541817737da8412	dev	Yes	Yes
5391447fae6209bb21a89e6a5a6583cac1af9b4b	beta/stable	Yes	No

[stuartmorgan-g]

I see what happened; prior to flutter/engine#6973 the engine was erroring out if main_path and packages_path were null, even though snapshot mode didn't actually use them. It turns out that landed slightly after Flutter's stable branch was cut.

Since passing a non-null value would log warnings with master, there's no way to cleanly support both stable and master (and the code to pass something other than null in a way that would compile against either version would be ugly, since the fields were renamed). So this falls under https://github.com/google/flutter-desktop-embedding/tree/master/library#caveats, and the solution is to use something newer than Flutter stable with current versions of FDE.

Closing, since #241 is already tracking making this failure less mysterious.