Arch Linux User Repository

@juancarlospaco this is easily done on your own system, not in a PKGBUILD, given that building packages runs as root:

sudo groupadd unrealengine-users
sudo usermod -aG unrealengine-users (your-username)
sudo chown -R root:unrealengine-users /opt/unreal-engine
sudo chmod -R 775 /opt/unreal-engine

Permission issues like this are already mentioned on the UE Arch wiki page: https://wiki.archlinux.org/title/Unreal_Engine_4#Installing_from_the_AUR

This is a user system problem; I already did what I could without needing users to do the above by giving the 777 permissions. If it still gives you trouble, you'll have to use the example to solve it or change the install location to somewhere you have user permissions by default (as I cannot do this for you).

Will update to 5.0 when it is released.

Anyone else want to maintain it?

Disowning my maintainership because I moved away from Arch and honestly can't dedicate the resources to keep troubleshooting issues. I'm sure someone can package better than me anyway.

How can i fix this?

[2907/4264] Compile Module.LevelSnapshotsEditor.cpp Trace file written to /home/wild/Library/Logs/Unreal Engine/LocalBuildLogs/UBA-UnrealEditor-Linux-DebugGame.uba with size 605.3kb Total time in Unreal Build Accelerator local executor: 2617.28 seconds Total execution time: 2646.45 seconds Took 2,646.86s to run dotnet, ExitCode=6 UnrealBuildTool failed. See log for more details. (/home/wild/Library/Logs/Unreal Engine/LocalBuildLogs/UBA-UnrealEditor-Linux-DebugGame.txt) AutomationTool executed for 0h 44m 45s AutomationTool exiting with ExitCode=6 (6) RunUAT ERROR: AutomationTool was unable to run successfully. Exited with code: 6 Error: Build failed; try searching the output for suspicious messages. ==> Entering fakeroot environment... ==> Starting package()... cp: cannot stat '/home/wild/.cache/yay/unreal-engine/src/unreal-engine/LocalBuilds/Engine/Linux/*': No such file or directory ==> ERROR: A failure occurred in package(). Aborting... -> error making: unreal-engine-exit status 4 -> Failed to install the following packages. Manual intervention is required: unreal-engine - exit status 4

@Neko-san I just noticed that you build the engine as an Installed Build, but that means that we're forgoing the benefits that Unreal affords for source-built builds, while still having to compile.

This is of-course ok if the intention is to distribute a customized, pre-built version of the engine to team-members (non-customized would be better off w/ unreal-engine-bin), but I imagine that must be a relatively rare use-case for Linux users?

So I'm wondering then if targeting an "installed build" is perhaps a mistake? If it's intentional, then perhaps it would be good to point that out somewhere? (apologies if I simply missed it)

@KarthikJay I also get that problem; a faster way than compiling single-threaded is to re-run the compilation process several times, which eventually succeeded for me.

I keep getting generated.h file not found errors when compiling?:

.cache/paru/clone/unreal-engine/src/unreal-engine/Engine/Plugins/Experimental/LearningAgents/Source/Learning/Private/LearningAdamOptimizer.cpp:8:10: fatal error: 'Learning.ispc.generated.h' file not found
    8 | #include "Learning.ispc.generated.h"
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
 Compile Module.Learning.cpp: Exited with error code 1 . The build will fail.

Any ideas on how to get the build graph to build in the right way with multiple threads?

That's really strange because the correct archive URL does seem point to the proper filename (https://github.com/EpicGames/UnrealEngine/blob/cecad67fcf69f0bec08bda2e8d6e1801930962c0/Engine/Build/BatchFiles/Linux/SetupToolchain.sh#L28), but according what you've shown it just ignores it then tries to extract an HTML file instead with a filename missing the native-linux prefix from the cache... For now, I'll implement grabbing the SDK manually in the PKGBUILD.

I'm not sure anymore as I've fiddled a bit with everything but I believe the "cd" line may interfere with finding the scripts and their relative paths. (I can't check now as the build is going on now and I'd rather let it finish.) Here I've deleted that line.

Anyway your update fixes half of the problem.

In "SetupToolchain.sh" it does this:

Downloading toolchain.
Using cached toolchain.
Extracting toolchain.
tar: This does not look like a tar archive

gzip: stdin: not in gzip format
tar: Child returned status 1
tar: Error is not recoverable: exiting now

Debugging the script ...

TOOLCHAIN_VERSION=v22_clang-16.0.6-centos7
TOOLCHAIN_URL=http://cdn.unrealengine.com/Toolchain_Linux/native-linux-v22_clang-16.0.6-centos7.tar.gz
Downloading toolchain.
Using cached toolchain.
Extracting toolchain. '../.git/ue4-sdks/v22_clang-16.0.6-centos7.tar.gz'
cmd=tar -xvf ../.git/ue4-sdks/v22_clang-16.0.6-centos7.tar.gz -C Extras/ThirdPartyNotUE/SDKs/HostLinux/Linux_x64/
tar: This does not look like a tar archive

The relative path ../.git/ue4-sdks/v22_clang-16.0.6-centos7.tar.gz is correct as the cwd is "Engine".

The file however contains ...

<html>
<head><title>301 Moved Permanently</title></head>
<body>
<center><h1>301 Moved Permanently</h1></center>
<center>CloudFront</center>
</body>
</html>

I've downloaded the archive by hand myself (using wget) and it's a proper tar.gz but it's called native-linux-v22_clang-16.0.6-centos7.tar.gz

wget http://cdn.unrealengine.com/Toolchain_Linux/native-linux-v22_clang-16.0.6-centos7.tar.gz

I've removed the broken file and symbolically linked to the one I've downloaded myself and the build is going further.

So the culprit is thus SetupToolchain.sh and I'm surprised it works for anybody.

Thanks for your help.

Let me know if it does it again with this push, and I'll see what I can do from there

Okay, so I found the reason and it's pretty stupid. I'll update the PKGBUILD in a moment.