Failed to pull source: unable to determine source type of '/usr/share/snapcraft/extensions/ros2'
Metadata
Current evaluation
The :8_core22 image stages extensions under site-packages while Snapcraft expects them under /usr/share; the mismatch remains open, with a symlink workaround reported.
Suggested action: keep open
Reason: Maintainer @lengau confirmed that the image is "not organizing the extension scripts to somewhere where they'd be expected," and current code still resolves them under sys.prefix/share rather than the reported site-packages location. The exact image digest and reproduction are clear, although a complete ROS build remains unsupported there because the plugin depends on build snaps.
Evaluated by: mr-cal-bot
Impact:
58
Quick Win:
35
Complexity:
30
Confidence:
91
Actionability:
86
Issue body
Initially opened this issue https://github.com/canonical/snapcraft/issues/5721
Since I did not get any response I suspect it was the wrong repository to address the docker issue.
### Bug Description
Snapcraft fails to find its own extensions:
```
2025-08-22T07:04:11.745Z [snapcraft] Initializing parts lifecycle
2025-08-22T07:04:13.827Z [snapcraft] **Failed to pull source: unable to determine source type of '/usr/share/snapcraft/extensions/ros2'.**
2025-08-22T07:04:13.828Z [snapcraft] Full execution log: '/root/.local/state/snapcraft/log/snapcraft-20250822-070411.734995.log'
2025-08-22T07:04:13.956Z [pebble] Service "snapcraft" stopped unexpectedly with code 1
```
extensions path is hardcoded here:
`usr/share/snapcraft/extensions`
https://github.com/canonical/snapcraft/blob/df4ec6775a28d4a345c93d9f83a1193c0abc1c9d/snapcraft/extensions/extension.py#L135
but in latest docker container for snapcraft 8, ghcr.io/canonical/snapcraft:8_core22 (24050a02f9fe)
extensions are located here:
`/usr/lib/python3.10/site-packages/extensions/ros2`
### To Reproduce
```bash
git clone https://github.com/snapcraft-docs/ros2-talker-listener-core22.git
cd ros2-talker-listener-core22
docker run -v $(pwd):/project ghcr.io/canonical/snapcraft:8_core22
```
### Environment
Ubuntu 22.04 LTS, Docker 28.3.1
### snapcraft.yaml
```yaml
name: ros2-talker-listener
version: '0.1'
summary: ROS 2 Talker/Listener Example
description: |
This example launches a ROS 2 talker and listener.
confinement: devmode
base: core22
parts:
ros-demos:
plugin: colcon
source: https://github.com/ros2/demos.git
source-branch: humble
source-subdir: demo_nodes_cpp
stage-packages: [ros-humble-ros2launch]
apps:
ros2-talker-listener:
command: opt/ros/humble/bin/ros2 launch demo_nodes_cpp talker_listener.launch.py
extensions: [ros2-humble]
```
### Relevant log output
```shell
docker run -v $(pwd):/project ghcr.io/canonical/snapcraft:8_core22
2025-08-22T07:04:05.252Z [pebble] Started daemon.
2025-08-22T07:04:05.284Z [pebble] POST /v1/services 16.330855ms 202 (http+unix)
2025-08-22T07:04:05.300Z [pebble] Service "snapcraft" starting: /bin/run-snapcraft.sh [ pack ]
2025-08-22T07:04:05.305Z [snapcraft]
2025-08-22T07:04:05.305Z [snapcraft] WARNING: apt does not have a stable CLI interface. Use with caution in scripts.
2025-08-22T07:04:05.305Z [snapcraft]
2025-08-22T07:04:05.777Z [snapcraft] Get:1 http://archive.ubuntu.com/ubuntu jammy InRelease [270 kB]
2025-08-22T07:04:05.922Z [snapcraft] Get:2 http://security.ubuntu.com/ubuntu jammy-security InRelease [129 kB]
2025-08-22T07:04:05.938Z [snapcraft] Get:3 http://archive.ubuntu.com/ubuntu jammy-updates InRelease [128 kB]
2025-08-22T07:04:05.981Z [snapcraft] Get:4 http://archive.ubuntu.com/ubuntu jammy-backports InRelease [127 kB]
2025-08-22T07:04:06.031Z [snapcraft] Get:5 http://archive.ubuntu.com/ubuntu jammy/restricted amd64 Packages [164 kB]
2025-08-22T07:04:06.080Z [snapcraft] Get:6 http://archive.ubuntu.com/ubuntu jammy/main amd64 Packages [1792 kB]
2025-08-22T07:04:06.249Z [snapcraft] Get:7 http://archive.ubuntu.com/ubuntu jammy/multiverse amd64 Packages [266 kB]
2025-08-22T07:04:06.272Z [snapcraft] Get:8 http://archive.ubuntu.com/ubuntu jammy/universe amd64 Packages [17.5 MB]
2025-08-22T07:04:06.298Z [snapcraft] Get:9 http://security.ubuntu.com/ubuntu jammy-security/multiverse amd64 Packages [48.5 kB]
2025-08-22T07:04:06.317Z [pebble] GET /v1/changes/1/wait 1.032101461s 200 (http+unix)
2025-08-22T07:04:06.318Z [pebble] Started default services with change 1.
2025-08-22T07:04:06.408Z [snapcraft] Get:10 http://security.ubuntu.com/ubuntu jammy-security/universe amd64 Packages [1271 kB]
2025-08-22T07:04:06.948Z [snapcraft] Get:11 http://security.ubuntu.com/ubuntu jammy-security/restricted amd64 Packages [5235 kB]
2025-08-22T07:04:07.779Z [snapcraft] Get:12 http://security.ubuntu.com/ubuntu jammy-security/main amd64 Packages [3253 kB]
2025-08-22T07:04:08.583Z [snapcraft] Get:13 http://archive.ubuntu.com/ubuntu jammy-updates/restricted amd64 Packages [5430 kB]
2025-08-22T07:04:09.285Z [snapcraft] Get:14 http://archive.ubuntu.com/ubuntu jammy-updates/universe amd64 Packages [1575 kB]
2025-08-22T07:04:09.452Z [snapcraft] Get:15 http://archive.ubuntu.com/ubuntu jammy-updates/multiverse amd64 Packages [75.9 kB]
2025-08-22T07:04:09.465Z [snapcraft] Get:16 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 Packages [3569 kB]
2025-08-22T07:04:09.856Z [snapcraft] Get:17 http://archive.ubuntu.com/ubuntu jammy-backports/main amd64 Packages [83.2 kB]
2025-08-22T07:04:09.860Z [snapcraft] Get:18 http://archive.ubuntu.com/ubuntu jammy-backports/universe amd64 Packages [35.2 kB]
2025-08-22T07:04:09.986Z [snapcraft] Fetched 40.9 MB in 5s (8818 kB/s)
2025-08-22T07:04:09.986Z [snapcraft] Reading package lists...
2025-08-22T07:04:10.683Z [snapcraft] Building dependency tree...
2025-08-22T07:04:10.813Z [snapcraft] Reading state information...
2025-08-22T07:04:10.827Z [snapcraft] 8 packages can be upgraded. Run 'apt list --upgradable' to see them.
2025-08-22T07:04:11.745Z [snapcraft] Initializing parts lifecycle
2025-08-22T07:04:13.827Z [snapcraft] Failed to pull source: unable to determine source type of '/usr/share/snapcraft/extensions/ros2'.
2025-08-22T07:04:13.828Z [snapcraft] Full execution log: '/root/.local/state/snapcraft/log/snapcraft-20250822-070411.734995.log'
2025-08-22T07:04:13.956Z [pebble] Service "snapcraft" stopped unexpectedly with code 1
2025-08-22T07:04:13.956Z [pebble] Service "snapcraft" on-failure action is "shutdown", triggering failure shutdown
2025-08-22T07:04:13.956Z [pebble] Server exiting! Reason: <nil>
```
### Additional context
_No response_
Evaluation history
| Date | Model | Scores | Action | Summary |
|---|---|---|---|---|
| stealth/space-bunny-alpha |
Impact:
58
Quick Win:
35
Complexity:
30
Confidence:
91
Actionability:
86
|
keep open | The :8_core22 image stages extensions under site-packages while Snapcraft expects them under /usr/share; the mismatch remains open, with a symlink workaround reported. | |
| qwen/qwen3.6-35b-a3b |
Impact:
30
Quick Win:
13
Complexity:
30
Confidence:
70
Actionability:
60
|
keep open | Snapcraft Docker image fails to locate extensions because get_extensions_data_dir() returns /usr/share/snapcraft/extensions but extensions are installed in site-packages. | |
| qwen/qwen3.8-27b |
Impact:
50
Quick Win:
30
Staleness:
55
Complexity:
40
Confidence:
80
Support Request:
10
|
keep open | Snapcraft 8 Docker image (ghcr.io/canonical/snapcraft:8_core22) fails to resolve ros2 extension: get_extensions_data_dir() returns /usr/share/snapcraft/extensions but extensions live in site-packages. Triaged, acknowledged by maintainer, workaround shared, still open. | |
| qwen/qwen3.8-27b |
Impact:
45
Quick Win:
27
Staleness:
50
Complexity:
40
Confidence:
75
Support Request:
10
|
keep open | Snapcraft 8 Docker image (snapcraft-rocks) installs extensions under site-packages but code expects /usr/share/snapcraft/extensions, breaking all extension usage. Triaged, acknowledged by maintainer, workaround via symlink provided, no fix yet. | |
| qwen/qwen3.6-35b-a3b |
Staleness:
55
Complexity:
20
Confidence:
85
Support Request:
0
|
keep open | Bug report for snapcraft Docker image where extension paths are misconfigured, causing build failures. Triaged and acknowledged by maintainers, with a community workaround provided but no official fix yet. | |
| qwen3.6-35b-a3b-mtp-q6 |
Staleness:
60
Complexity:
30
Confidence:
85
Support Request:
10
|
keep open | Snapcraft fails to locate extensions in Docker due to a hardcoded path mismatch. Triaged and acknowledged by maintainers, with a community workaround provided but no official fix yet. |
Update history
No update history recorded yet.
Related work
-
Duplicate Of:
canonical/snapcraft#5721
(confidence 99%)
The reporter explicitly identifies this as the same issue in the main Snapcraft repository, which remains open with the same path mismatch.
Related issues
| Issue | Project | State | Summary | Similarity |
|---|---|---|---|---|
| #5721 Failed to pull source: unable to determine source type of '/usr/share/snapcraft/extensions/ros2'. | snapcraft | open | Snapcraft's 8_core22 container resolves extension data under /usr/share while the image installs it in site-packages, breaking ROS 2 builds; the path mismatch remains in current code. |