UltiMaker Cura is not a proper AppImage

[HarlemSquirrel]

Cura Version

5.6.0

Operating System

Pop!_OS 22.04

Printer

Lulzbot TAZ 6

Reproduction steps

1. Use appimaged to manage AppImages
2. Place Cura AppImage in ~/Applications/
3. Observe appimaged set the system shortcut for Cura
4. Launch Cura from system applications

Actual results

See system notice

UltiMaker Cura is not a proper AppImage
Too short Please ask author to fix it

Cura runs fine otherwise except the changelog splash screen appears at every launch.

Expected results

No system notice

Add your .zip and screenshots here ⬇️

cura.log

[Steve-Tech]

I get the same message also, on Debian Testing with appimaged 817. Cura does run fine though.

[nallath]

Uh. That's a very... helpfull message from the OS. Is there any way that it can tell us why it believes it to be an invalid appimage?

[HarlemSquirrel]

Looks like the message is coming from here:

https://github.com/probonopd/go-appimage/blob/09fd0186774aefa2351c42b4bb22f92ce0c4f235/src/appimaged/appwrapper.go#L35-L49

[Steve-Tech]

This file seems to throw the error: https://github.com/probonopd/go-appimage/blob/09fd0186774aefa2351c42b4bb22f92ce0c4f235/internal/helpers/updateinformation.go

It seems to be related to update information, so yeah it has no impact on usability, but also seems like a simple fix (but I have no experience with building AppImages).

Edit: Line 92 specifically which get called when updateinformation != "": https://github.com/probonopd/go-appimage/blob/09fd0186774aefa2351c42b4bb22f92ce0c4f235/internal/helpers/updateinformation.go#L92

[Steve-Tech]

So the .upd_info section seems to contain guess while other appimages leave it blank. According to the AppImage spec the correct options are zsync, gh-releases-zsync, pling-v1-zsync, or bintray-zsync.

stephen@Stephens-PC:~/Applications$ readelf -p .upd_info UltiMaker-Cura-5.6.0-linux-X64.AppImage

String dump of section '.upd_info':
[     0]  guess

stephen@Stephens-PC:~/Applications$ readelf -p .upd_info balenaEtcher-1.7.9-x64.AppImage

String dump of section '.upd_info':
No strings found in this section.

Although I feel like appimaged should skip validation when the method isn't supported, unless guess is documented somewhere, I think the bug is in Cura.

[Steve-Tech]

GitHub's search reveals this line to be the likely problem:

Cura/packaging/AppImage-builder/AppImageBuilder.yml.jinja

Line 78 in 234a811

update-information: guess

I'd recommend removing it, or setting it to "", depending on if it's actually required or not. Or alternatively implementing the creation of a .zsync file and using something like gh-releases-zsync|Ultimaker|Cura|latest|UltiMaker-Cura-*-linux-X64.AppImage.zsync