xdg-open fails on Kububtu (Ubuntu with KDE desktop) only from Medley shell

[RyanBurnside]

Describe the bug
xdg-open fails when run from within Medley on Kubuntu 24.04.
Kubuntu is one of the forms of Ubuntu that ships with KDE as the desktop. Nothing too uncommon nor exotic.

I noticed this while troubleshooting the side documentation buttons on the desktop.
I walked down through the source code for the buttons until I reached a callback to "ShellCommand" which runs a concatenated form of the xdg-open location and the url (which I verified to both be correct).

I reconstructed the command manually and tried it from the real Linux Bash shell and it ran just fine. I do have xdg-utils installed and can run xdg-open from the host.

ShellBrowser-warnings-17650.txt

To Reproduce
Click one of the documentation calling buttons on the side in Kubuntu.
Check the error logs of the /tmp directory which it writes to.

Expected behavior
I would have expected it to open my system set default browser to the documentation pdf.

Screenshots

Context (please complete the following information):

• Are you using online.interlisp.org? [no]
• OS: Kubuntu 24.04, KDE Plasma Version 5.27.12, Graphics Platform: X11
• OS Version: 24.04
• Display/window system: X11
• Host arch: x86_64
• Maiko version: Latest packaged version from Website
• IL:MAKESYSDATE: [ date ] or (il:print-lisp-information): copy-paste or screenshot this

Additional context
I'm not sure if it's a KDE issue or if it also applies to Gnome as well.
xdg-open DOES run from the host Bash shell.
The version is xdg-open 1.1.3

[RyanBurnside]

I spent (much) more time today trying to get to the root of this issue.
I believe the problem lies in a bad "snap" installation of Firefox and Chrome.
"snap" is one packaging system that Ubuntu among others are moving to.

I ended up doing some battle with snapd (the snap manager) and after much fussing managed to remove Firefox and reinstall it from the Kubuntu graphical front end.

It now seems to work with the existing code, helpfully bringing up the various documents.

I believe we can mark this as "closed" but perhaps snap configurations may give us trouble in the future. Something to keep in mind.

[nbriggs]

Well, it's just another thing to blame when things go wrong. Did you try rebooting? Turning it off and on again? Did you try recompiling? Have you got spaces in your directory name? Are you using snap packaging? ;-)

[fghalasz]

Realize this issue is closed. But documenting my findings on the issue here just in case we need the information in the future.

Removing and reinstalling Firefox (and installing Chromium) on Kubuntu 24.04 did not fix this for me. I did the removal and reinstall from the command line, not from GUI. Always using the snap versions.

Spent a lot of time looking into this issue. In the end it does appear to be a bug in Kubuntu 24.04, specifically in kde-open (which is what xdg-open on KDE calls to do its work).

Here is some of what I discovered:

1. (ShellBrowse) and (ShellOpen) work fine on Kubuntu 25.10 (without any interventions).

2. On 24.04, running xdg-open /home/frank/test.html within a (CHAT 'SHELL) window works just fine.

3. On 24.04, (ShellCommand "xdg-open /home/frank/test.html") fails. (Not all that surprising since (CHAT 'SHELL) and (CREATE-PROCESS-STREAM) - which is the core of (ShellOpen), (ShellBrowse) and (ShellCommand) - use different code in Maiko to fork the shell and in many installations will invoke different shells (e.g. bash versus dash on standard Kubuntu).

4. On 24.04, (ShellCommand "kde-open /home/frank/test.html") also fails. BUT both (ShellCommand "firefox /home/frank/test.html") and (ShellCommand "chromium /home/frank/test.html") both succeed.

5. On 24.04, if the shell is controlled (both use bash or both use dash), the printenv for (CHAT 'SHELL) and (ShellCommand "printenv") are the same in all ways that count - so difference between CHAT and ShellCommand is not in the env variables.

6. Workaround on 24.04: (SETQ ShellOpener "/usr/bin/firefox") and (SETQ ShellBrowser "/usr/bin/firefox") (or chromium equivs). This will bypass the brokenness of kde-open and just invoke firefox or chromium directly.

[masinter]

I think the issue can be closed once we update the Install and Run instructions for the workaround and the reasons for it.

[RyanBurnside]

@fghalasz I very much appreciate you going to the trouble to install my version of Kubuntu.
Hopefully it was a quick VM spinup to test. :)
Nice to see they fixed it in the next version.

Thank you.