Building snaps with `kde-neon` extension is not working
Metadata
Current evaluation
Snapcraft Docker images (ghcr.io/canonical/snapcraft:8_core22) fail to build snaps using the kde-neon extension: 'unable to determine source type of /usr/share/snapcraft/extensions/desktop/kde-neon'. Root cause is snapcraft's get_extensions_data_dir() hard-coding sys.prefix, which resolves to the wrong path in the Docker image. Confirmed still broken for core24/kde-neon-6 and GNOME in 2025.
Suggested action: keep open
Reason: A maintainer (tigarmo) acknowledged the report and confirmed extensions 'probably need to do some work to support', and the reporter traced the root cause to snapcraft's get_extensions_data_dir() hard-coding sys.prefix. The issue was re-confirmed still broken in 2025 (core24/kde-neon-6 and GNOME), so it remains a valid, open bug. It is not stale-irrelevant and not a support question, so it should stay open pending a fix.
Impact:
60
Quick Win:
27.0
Staleness:
45
Complexity:
55
Confidence:
70
Support Request:
15
Issue body
Hello, I recently found out about this repository and its intention to be the official way to build Snap packages in Docker.
I tried to build our Snap packages using `ghcr.io/canonical/snapcraft:8_core22` but sadly it did not work as expected.
The problem seems to be when using the `kde-neon` extension.
Consider the following `snap/snapcraft.yaml` example adapted from the [official guide for Qt5/KF applications](https://snapcraft.io/docs/qt5-kde-applications):
```yaml
name: kcalc
version: 19.08.0
grade: stable
adopt-info: kcalc
confinement: strict
base: core22
apps:
kcalc:
common-id: org.kde.kcalc.desktop
command: kcalc
extensions:
- kde-neon
plugs:
- home
- opengl
- network
- network-bind
- pulseaudio
slots:
session-dbus-interface:
interface: dbus
name: org.kde.kcalc.desktop
bus: session
parts:
kcalc:
parse-info:
- usr/share/metainfo/org.kde.kcalc.appdata.xml
plugin: cmake
build-snaps:
- kf5-5-111-qt-5-15-11-core22-sdk
build-packages:
- libmpfr-dev
- libgmp-dev
- libkf5doctools-dev
stage-packages:
- libmpfr6
- libgmp10
source: https://download.kde.org/stable/applications/19.08.0/src/kcalc-19.08.0.tar.xz
cmake-parameters:
- "-DKDE_INSTALL_USE_QT_SYS_PATHS=ON"
- "-DCMAKE_INSTALL_PREFIX=/usr"
- "-DCMAKE_BUILD_TYPE=Release"
- "-DENABLE_TESTING=OFF"
- "-DBUILD_TESTING=OFF"
- "-DKDE_SKIP_TEST_SETTINGS=ON"
```
The above Snapcraft file does not build using the `ghcr.io/canonical/snapcraft:8_core22` image:
```
$ docker run -it -v `pwd`:/project ghcr.io/canonical/snapcraft:8_core22
2024-04-28T21:36:27.568Z [pebble] Started daemon.
2024-04-28T21:36:27.598Z [pebble] POST /v1/services 18.095676ms 202
2024-04-28T21:36:27.599Z [pebble] Started default services with change 1.
2024-04-28T21:36:27.610Z [pebble] Service "snapcraft" starting: /bin/run-snapcraft.sh [ pack ]
2024-04-28T21:36:27.634Z [snapcraft]
2024-04-28T21:36:27.635Z [snapcraft] WARNING: apt does not have a stable CLI interface. Use with caution in scripts.
2024-04-28T21:36:27.635Z [snapcraft]
2024-04-28T21:36:27.925Z [snapcraft] Get:1 http://archive.ubuntu.com/ubuntu jammy InRelease [270 kB]
2024-04-28T21:36:27.983Z [snapcraft] Get:2 http://security.ubuntu.com/ubuntu jammy-security InRelease [110 kB]
2024-04-28T21:36:28.491Z [snapcraft] Get:3 http://archive.ubuntu.com/ubuntu jammy-updates InRelease [119 kB]
2024-04-28T21:36:28.640Z [snapcraft] Get:4 http://archive.ubuntu.com/ubuntu jammy-backports InRelease [109 kB]
2024-04-28T21:36:28.787Z [snapcraft] Get:5 http://archive.ubuntu.com/ubuntu jammy/multiverse amd64 Packages [266 kB]
2024-04-28T21:36:28.939Z [snapcraft] Get:6 http://archive.ubuntu.com/ubuntu jammy/universe amd64 Packages [17.5 MB]
2024-04-28T21:36:29.099Z [snapcraft] Get:7 http://security.ubuntu.com/ubuntu jammy-security/main amd64 Packages [1755 kB]
2024-04-28T21:36:32.254Z [snapcraft] Get:8 http://security.ubuntu.com/ubuntu jammy-security/multiverse amd64 Packages [44.7 kB]
2024-04-28T21:36:32.291Z [snapcraft] Get:9 http://security.ubuntu.com/ubuntu jammy-security/restricted amd64 Packages [2265 kB]
2024-04-28T21:36:32.380Z [snapcraft] Get:10 http://archive.ubuntu.com/ubuntu jammy/restricted amd64 Packages [164 kB]
2024-04-28T21:36:32.391Z [snapcraft] Get:11 http://archive.ubuntu.com/ubuntu jammy/main amd64 Packages [1792 kB]
2024-04-28T21:36:32.705Z [snapcraft] Get:12 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 Packages [2035 kB]
2024-04-28T21:36:33.301Z [snapcraft] Get:13 http://archive.ubuntu.com/ubuntu jammy-updates/universe amd64 Packages [1370 kB]
2024-04-28T21:36:33.528Z [snapcraft] Get:14 http://archive.ubuntu.com/ubuntu jammy-updates/restricted amd64 Packages [2339 kB]
2024-04-28T21:36:33.832Z [snapcraft] Get:15 http://archive.ubuntu.com/ubuntu jammy-updates/multiverse amd64 Packages [51.1 kB]
2024-04-28T21:36:33.846Z [snapcraft] Get:16 http://archive.ubuntu.com/ubuntu jammy-backports/main amd64 Packages [81.0 kB]
2024-04-28T21:36:33.846Z [snapcraft] Get:17 http://archive.ubuntu.com/ubuntu jammy-backports/universe amd64 Packages [31.9 kB]
2024-04-28T21:36:34.320Z [snapcraft] Get:18 http://security.ubuntu.com/ubuntu jammy-security/universe amd64 Packages [1077 kB]
2024-04-28T21:36:37.034Z [snapcraft] Fetched 31.4 MB in 9s (3359 kB/s)
2024-04-28T21:36:37.034Z [snapcraft] Reading package lists...
2024-04-28T21:36:39.910Z [snapcraft] Building dependency tree...
2024-04-28T21:36:40.215Z [snapcraft] Reading state information...
2024-04-28T21:36:40.273Z [snapcraft] 15 packages can be upgraded. Run 'apt list --upgradable' to see them.
2024-04-28T21:36:45.918Z [snapcraft] Starting Snapcraft 8.0.5
2024-04-28T21:36:45.918Z [snapcraft] Logging execution to '/root/.local/state/snapcraft/log/snapcraft-20240428-213645.910384.log'
2024-04-28T21:36:45.957Z [snapcraft] Running on amd64 for amd64
2024-04-28T21:36:45.966Z [snapcraft] Initializing parts lifecycle
2024-04-28T21:36:45.981Z [snapcraft] Failed to pull source: unable to determine source type of '/usr/share/snapcraft/extensions/desktop/kde-neon'.
2024-04-28T21:36:45.987Z [snapcraft] Full execution log: '/root/.local/state/snapcraft/log/snapcraft-20240428-213645.910384.log'
2024-04-28T21:36:46.344Z [pebble] Service "snapcraft" stopped unexpectedly with code 1
2024-04-28T21:36:46.344Z [pebble] Service "snapcraft" on-failure action is "shutdown", triggering failure shutdown
2024-04-28T21:36:46.344Z [pebble] Server exiting!
```
The same Snapcraft file does start building correctly in Ubuntu with the regular `snapcraft` command:
```
$ snapcraft --use-lxd --verbose
Starting Snapcraft 8.0.5
Logging execution to '/home/hhromic/.local/state/snapcraft/log/snapcraft-20240428-223554.190257.log'
Running on amd64 for amd64
Launching instance...
Starting instance
Starting Snapcraft 8.0.5
Logging execution to '/tmp/snapcraft.log'
Running on amd64 for amd64
Initializing parts lifecycle
Installing build-packages
Installing build-snaps
Pulling kcalc
Fetching stage-packages
Pulling kde-neon/sdk
Building kcalc
:: + cmake /root/parts/kcalc/src -G 'Unix Makefiles' -DKDE_INSTALL_USE_QT_SYS_PATHS=ON -DCMAKE_INSTALL_PREFIX=/usr -DCMAKE_BUILD_TYPE=Release -DENABLE_TESTING=OFF -DBUILD_TESTING=OFF -DKDE_SKIP_TEST_SETTINGS=ON
:: -- The C compiler identification is GNU 11.2.0
:: -- The CXX compiler identification is GNU 11.2.0
:: -- Detecting C compiler ABI info
:: -- Detecting C compiler ABI info - done
:: -- Check for working C compiler: /usr/bin/cc - skipped
:: -- Detecting C compile features
:: -- Detecting C compile features - done
:: -- Detecting CXX compiler ABI info
:: -- Detecting CXX compiler ABI info - done
...
```
> **Warning:** The kcalc build itself does not actually succeed in this example, but at least it does start building.
Is there something I'm doing wrong when using the `ghcr.io/canonical/snapcraft:8_core22` image or Snapcraft files using extensions is not yet supported by the images in this repository?
Evaluation history
| Date | Model | Scores | Action | Summary |
|---|---|---|---|---|
| qwen/qwen3.8-27b |
Impact:
60
Quick Win:
27.0
Staleness:
45
Complexity:
55
Confidence:
70
Support Request:
15
|
keep open | Snapcraft Docker images (ghcr.io/canonical/snapcraft:8_core22) fail to build snaps using the kde-neon extension: 'unable to determine source type of /usr/share/snapcraft/extensions/desktop/kde-neon'. Root cause is snapcraft's get_extensions_data_dir() hard-coding sys.prefix, which resolves to the wrong path in the Docker image. Confirmed still broken for core24/kde-neon-6 and GNOME in 2025. | |
| qwen/qwen3.6-35b-a3b |
Staleness:
75
Complexity:
30
Confidence:
85
Support Request:
10
|
needs triage | Reports kde-neon extension build failures in the snapcraft Docker image due to a hardcoded Python path mismatch. Confirmed unresolved in newer versions, awaiting maintainer investigation. | |
| qwen3.6-35b-a3b-mtp-q6 |
Staleness:
75
Complexity:
40
Confidence:
85
Support Request:
10
|
keep open | Bug in Snapcraft Docker/Rocks images where extensions fail to load due to incorrect Python sys.prefix path resolution. Validated across multiple extensions and Snapcraft versions, but remains unaddressed. | |
| qwen3.6-35b-a3b-mtp-q6 |
Staleness:
80
Complexity:
45
Confidence:
75
Support Request:
5
|
needs triage | Snapcraft Docker images fail to locate extensions due to incorrect sys.prefix path resolution. The issue persists across versions and remains open pending a fix. |
Update history
No update history recorded yet.
Related issues
| Issue | Project | State | Summary | Similarity |
|---|---|---|---|---|
| #1881963 extension: kde-neon fails on arm64 | snapcraft (launchpad) | closed | Abandoned due to inactivity. The kde-neon extension fails on arm64 because the kde-frameworks-5-core18 snap lacks arm64 builds, causing snapcraft to fail during prerequisite installation. | |
| #5128 KDE Neon 6 broken on arm64 | snapcraft | open | kde-neon-6 extension fails on arm64 because the kf6-core22 content snap is missing Qt6 libraries (73MB vs 2GB amd64). Filed 682 days ago, no maintainer response, only 1 user comment. Root cause is in the external KDE content snap, not snapcraft code. |