Single-instance plugin D-Bus naming violates Flatpak/D-Bus conventions - causing Flathub rejections

[chrox]

Describe the bug

Summary

The Tauri single-instance plugin's D-Bus service naming pattern is incompatible with Flatpak/Flathub requirements and violates D-Bus naming conventions, causing Tauri apps to be rejected from Flathub.

Issue Details

Current Behavior

The single-instance plugin uses D-Bus service names in the format: org.{appId}.SingleInstance

For example, an app with:

• Flatpak ID: me.amankhanna.opendeck
• Tauri app ID: opendeck

Creates D-Bus service: org.opendeck.SingleInstance

Problem

Flathub's flatpak-builder-lint tool rejects this pattern because:

1. The D-Bus service name doesn't match the app's reverse-DNS Flatpak ID
2. It violates D-Bus naming conventions which require owned names to be under the application's namespace
3. It creates potential naming conflicts between different apps

Impact

• Flatpak maintainers have rejected exception requests for this pattern
• Two existing Tauri apps with exceptions (com.bilingify.readest and dev.mrquantumoff.mcmodpackmanager) will have their exceptions removed
• Flathub maintainers have stated they will block all Tauri apps if this isn't fixed
• Affects all Tauri apps using the single-instance plugin on Flatpak/Snap

References

• Original PR discussion: exceptions: allow finish-args-own-name-org.opendeck.SingleInstance for me.amankhanna.opendeck flathub-infra/flatpak-builder-lint#819
• Tauri single-instance docs: https://v2.tauri.app/plugin/single-instance/#usage-in-snap-and-flatpak
• D-Bus naming conventions: https://dbus.freedesktop.org/doc/dbus-specification.html#message-bus-names

Additional Context

Quote from Flathub maintainer (bbhtt):

"It needs to follow the appid not use a random dbus name that starts with org.. That's literally how everything else works including it is how things should be done per the dbus spec. [...] We will block all Tauri apps if we have to."

This is a critical issue for the Tauri ecosystem's Flatpak/Linux distribution story.

Reproduction

No response

Expected behavior

No response

Full tauri info output

[✔] Environment
    - OS: Mac OS 15.6.1 arm64 (X64)
    ✔ Xcode Command Line Tools: installed
    ✔ Xcode: 26.2
    ✔ rustc: 1.92.0 (ded5c06cf 2025-12-08)
    ✔ cargo: 1.92.0 (344c4567c 2025-10-21)
    ✔ rustup: 1.28.2 (e4f3ad6f8 2025-04-28)
    ✔ Rust toolchain: stable-aarch64-apple-darwin (default)
    - node: 22.9.0
    - pnpm: 10.25.0
    - yarn: 1.22.22
    - npm: 10.9.1

[-] Packages
    - tauri 🦀: 2.9.5
    - tauri-build 🦀: 2.5.3
    - wry 🦀: 0.53.5
    - tao 🦀: 0.34.5
    - @tauri-apps/api  ⱼₛ: 2.9.1
    - @tauri-apps/cli  ⱼₛ: 2.9.6

[-] Plugins
    - tauri-plugin-persisted-scope 🦀: 2.3.4
    - @tauri-apps/plugin-persisted-scope  ⱼₛ: not installed!
    - tauri-plugin-fs 🦀: 2.4.4
    - @tauri-apps/plugin-fs  ⱼₛ: 2.4.4
    - tauri-plugin-cli 🦀: 2.4.1
    - @tauri-apps/plugin-cli  ⱼₛ: 2.4.1
    - tauri-plugin-dialog 🦀: 2.4.2
    - @tauri-apps/plugin-dialog  ⱼₛ: 2.4.2
    - tauri-plugin-log 🦀: 2.7.1
    - @tauri-apps/plugin-log  ⱼₛ: 2.7.1
    - tauri-plugin-updater 🦀: 2.9.0
    - @tauri-apps/plugin-updater  ⱼₛ: 2.9.0
    - tauri-plugin-window-state 🦀: 2.4.1
    - @tauri-apps/plugin-window-state  ⱼₛ: not installed!
    - tauri-plugin-haptics 🦀: 2.3.2
    - @tauri-apps/plugin-haptics  ⱼₛ: 2.3.2
    - tauri-plugin-websocket 🦀: 2.4.1
    - @tauri-apps/plugin-websocket  ⱼₛ: 2.4.1
    - tauri-plugin-process 🦀: 2.3.1
    - @tauri-apps/plugin-process  ⱼₛ: 2.3.1
    - tauri-plugin-http 🦀: 2.5.4
    - @tauri-apps/plugin-http  ⱼₛ: 2.5.4
    - tauri-plugin-os 🦀: 2.3.2
    - @tauri-apps/plugin-os  ⱼₛ: 2.3.2
    - tauri-plugin-shell 🦀: 2.3.3
    - @tauri-apps/plugin-shell  ⱼₛ: 2.3.3
    - tauri-plugin-opener 🦀: 2.5.2
    - @tauri-apps/plugin-opener  ⱼₛ: 2.5.2
    - tauri-plugin-deep-link 🦀: 2.4.5
    - @tauri-apps/plugin-deep-link  ⱼₛ: 2.4.5
    - tauri-plugin-single-instance 🦀: 2.3.6
    - @tauri-apps/plugin-single-instance  ⱼₛ: not installed!

[-] App
    - build-type: bundle
    - CSP: frame-src 'self' blob: asset: http://asset.localhost https://*.stripe.com; font-src 'self' blob: data: asset: http://asset.localhost tauri: https://db.onlinewebfonts.com https://cdn.jsdelivr.net https://fonts.gstatic.com https://chinese-fonts-cdn.netlify.app https://cdnjs.cloudflare.com; default-src 'self' 'unsafe-inline' blob: data: customprotocol: asset: http://asset.localhost ipc: http://ipc.localhost; connect-src 'self' blob: data: asset: http://asset.localhost ipc: http://ipc.localhost http://*:* https://*:* https://*.sentry.io https://*.posthog.com https://*.deepl.com https://*.wikipedia.org https://*.wiktionary.org https://*.supabase.co https://*.readest.com wss://speech.platform.bing.com https://*.cloudflarestorage.com https://translate.googleapis.com https://translate.toil.cc https://*.microsofttranslator.com https://edge.microsoft.com https://*.googleusercontent.com; img-src 'self' blob: data: asset: http://asset.localhost https://* https://*:* http://* http://*:*; style-src 'self' 'unsafe-inline' blob: asset: http://asset.localhost https://cdn.jsdelivr.net https://fonts.googleapis.com https://chinese-fonts-cdn.netlify.app https://cdnjs.cloudflare.com; script-src 'self' 'unsafe-inline' 'unsafe-eval' blob: asset: http://asset.localhost https://*.sentry.io https://*.posthog.com  https://*.stripe.com
    - frontendDist: ../out
    - devUrl: http://localhost:3000/
    - framework: React (Next.js)
    - bundler: Webpack

Stack trace

Additional context

No response

[chrox]

@FabianLars Would you be able to take a look at this? This is blocking Flatpak distributions for Tauri apps. cc @nekename

[nekename]

Thanks @chrox for opening this!

I still don't know how this can be changed without breaking compatibility with older versions of the Tauri app in question.

It could possibly use a different service name when running in Flatpak, but then it wouldn't guarantee a single instance if you have both the unsandboxed and Flatpak versions installed.

[nekename]

If anyone implementing this needs a way to tell if running in Flatpak, here's a decent implementation: https://github.com/nekename/OpenDeck/blob/abd78ede7f08438d41ff325de92165d7736efb08/src-tauri/src/shared.rs#L56

[FabianLars]

Of course they'd lock the comments in the PR 🙄

Anyway, it's not that deep. We can quite easily fix this, we don't even need to care about flatpaks specifically in the plugin. Here's what i'll do:

1. fix the default dbus id/name. I don't know how i missed that org. prefix even though i approved the flatpak docs on that topic. This will only break the single instance mechanism if you have multiple installations of the same app with different versions which should be very rare.
2. for users like you that didn't use reverse domain name notation, or whatever reason they have for using a flatpak id different from the bundle id, i'll add a dbus_id setter function to the plugin.

[chrox]

You’re a true hero.

[nekename]

Of course they'd lock the comments in the PR 🙄

Yep ikr

Sounds good, can't think of a better way to do it

[nekename]

@FabianLars just an idea: you could check for the FLATPAK_ID environment variable instead of adding a dbus_id setter function.

This way, changes to the app source don't need to be made for Flatpak compatibility, and fewer changes need to be made to the plugin.

[FabianLars]

hmm guess we can do that. The setter function would have been the easiest part and i still think we'll need it but maybe i'll wait until it's requested.