Add Flatpak packaging for Bazzite/SteamOS

[Copilot]

• Create pkg/flatpak/ directory with Flatpak manifest (net.jdiskmark.JDiskMark.yml)
• Create AppStream metadata file (net.jdiskmark.JDiskMark.metainfo.xml)
• Create XDG desktop entry (net.jdiskmark.JDiskMark.desktop)
• Create launcher shell script (jdiskmark.sh)
• Add PNG icons from existing macOS ICNS
• Add create-flatpak ant target to build.xml
• Create GitHub Actions workflow (.github/workflows/flatpak-build.yml)
• Fix CI failure: replace Ant <delete> with rm -rf for cleanup of flatpak-build/ and flatpak-repo/ directories (flatpak-builder creates special files like var/run/adduser that Ant cannot delete)
• Remove --runtime-repo from flatpak build-bundle (the dl.flathub.org CDN returns HTTP 403 when Flatpak tries to auto-fetch the runtime); users must install org.freedesktop.Platform//24.08 from Flathub explicitly before installing the bundle
• Add INSTALL.md to the CI artifact (alongside the .flatpak bundle) documenting the correct three-step install process: add Flathub remote, install the required runtime (org.freedesktop.Platform//24.08), then run flatpak install --user ./jdiskmark-<version>.flatpak — and noting that flatpak install --from must not be used with .flatpak bundles

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Flatpak for Bazzit / SteamOS</issue_title>
<issue_description>Bazzite and SteamOS are linux gaming distros that have standardized on the Flatpak format.

A jdiskmark flatpak release would be helpful for gamers because we can help them validate their SD and SSD upgrades or high end NVMe performance.

objectives:

• create a Flatpak installer that can be used on a distro like Bazzite.
• create ant targets or maven goals to create and package the Flatpak

create new issues if not done:

• optional: create a gitlab workflow that will create a flatpak release on commit
• optional: successful Flathub submission</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Flatpak for Bazzit / SteamOS #115

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

[jamesmarkchan]

@copilot please try and resolve the build error that was encountered:
https://github.com/JDiskMark/jdm-java/actions/runs/22759478452/job/66134984705?pr=148

[Copilot]

@copilot please try and resolve the build error that was encountered:
https://github.com/JDiskMark/jdm-java/actions/runs/22759478452/job/66134984705?pr=148

Fixed in commit 10ff075.

The Flatpak bundle itself built successfully — the failure was only in the cleanup step. flatpak-builder creates special files like var/run/adduser inside the build directory that Ant's <delete> task can't remove. Replaced both <delete dir="..."/> calls with <exec executable="rm"> (rm -rf) which handles those files without issue.

[jamesmarkchan]

@copilot the uploaded flatpack from your workflow indicated this error when it was installed:

james@james-Blade:~/Downloads/jdiskmark-flatpak$ flatpak install --user ./jdiskmark-0.7.0.flatpak

Note that the directories 

'/var/lib/flatpak/exports/share'
'/home/james/.local/share/flatpak/exports/share'

are not in the search path set by the XDG_DATA_DIRS environment variable, so
applications installed by Flatpak may not appear on your desktop until the
session is restarted.

error: The application net.jdiskmark.JDiskMark/x86_64/master requires the runtime org.freedesktop.Platform/x86_64/24.08 which was not found

Is this something we should improve in the flatpack or is there something i need to do differently to install?

I have installed flatpak 1.14.6 on Ubuntu 24.04.4 LTS

[Copilot]

@copilot the uploaded flatpack from your workflow indicated this error when it was installed:

...

This is expected Flatpak behavior — a .flatpak bundle doesn't embed the runtime, so the system needs the org.freedesktop.Platform 24.08 runtime available locally.

Fixed in commit 14e0a1c by adding --runtime-repo=https://dl.flathub.org/repo/ to the flatpak build-bundle command. This embeds the Flathub URL into the bundle's metadata, so Flatpak can automatically offer to fetch the missing runtime from Flathub during install instead of just failing.

After the next CI run, the new bundle should install without that error on any system that has Flathub configured. For Ubuntu where Flathub may not be pre-configured, you can add it first with:

flatpak remote-add --user --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo

[JasmineRRod]

Is this expected? Can we improve the installer?

After reboot, I got this.

[jamesmarkchan]

@copilot look at feedback from @JasmineRRod above and advise.

#148 (comment)

[Copilot]

@copilot look at feedback from @JasmineRRod above and advise.

#148 (comment)

The error @JasmineRRod hit is caused by using the wrong install command. flatpak install --from is for .flatpakref text reference files — not .flatpak bundles. The correct command is:

flatpak install --user ./jdiskmark-0.7.0.flatpak

Fixed in commit 937370b by adding an INSTALL.md to the artifact (alongside the .flatpak bundle) that explains the correct command and common pitfalls. After the next CI run the downloaded zip will include both jdiskmark-0.7.0.flatpak and INSTALL.md.

[jamesmarkchan]

@copilot is this expected behavior?

[Copilot]

@copilot is this expected behavior?

Yes, that 403 is caused by the --runtime-repo=https://dl.flathub.org/repo/ flag I added — Flatpak tries to auto-fetch the runtime directly from the Flathub CDN, but that endpoint returns 403.

Fixed in commit 812c6d5:

• Removed --runtime-repo from the flatpak build-bundle command in build.xml
• Updated INSTALL.md to include an explicit prerequisite step — install the runtime from your locally-configured Flathub remote before installing the bundle:

flatpak remote-add --user --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
flatpak install --user flathub org.freedesktop.Platform//24.08
flatpak install --user ./jdiskmark-0.7.0.flatpak