Snapd error `cannot set "core.experimental.snapd-snap"` when repacking a core20 snap
Metadata
Current evaluation
Snapcraft stopped setting the removed snapd option in #5689 (8f02d3d48), fixing core20 builds in Snapcraft 8.12.
Resolution: closed resolved
Reason: Snapd 2.68.4 removed core.experimental.snapd-snap, but Snapcraft continued setting it. PR #5689 removed the obsolete setting, and the maintainer confirmed the core20 fix shipped in Snapcraft 8.12.
Evaluated by: mr-cal-bot
No scores available.
Issue body
### Bug Description
When building a core18 snap, the second run errors out. It works for a single build again after cleaning
### To Reproduce
1. Clone a core18 snap
2. `snapcraft --use-lxd`
3. `snapcraft --use-lxd`
### Environment
Kubuntu 25.04
### snapcraft.yaml
```yaml
name: git-nuke
base: core18
version: '0.1'
summary: The best thing since sliced bread
description: |
Too many branches? NOT ANY MORE!
grade: devel # must be 'stable' to release into candidate/stable channels
confinement: classic # use 'strict' once you have the right plugs and slots
parts:
my-part:
plugin: dump
source: .
apps:
git-nuke:
command: /snap/core18/current/usr/bin/python3 $SNAP/git-nuke
```
### Relevant log output
```shell
$ snapcraft_7 --use-lxd
Launching a container.
Waiting for container to be ready
Waiting for network to be ready...
error: cannot perform the following tasks:
- Run configure hook of "core" snap (run hook "configure": cannot set "core.experimental.snapd-snap": unsupported system option)
An error occurred when trying to execute 'snap set system experimental.snapd-snap=true' with 'LXD': returned exit code 1.
```
### Additional context
_No response_
Evaluation history
| Date | Model | Scores | Action | Summary |
|---|---|---|---|---|
| stealth/space-bunny-alpha | — | closed resolved | Snapcraft stopped setting the removed snapd option in #5689 (8f02d3d48), fixing core20 builds in Snapcraft 8.12. | |
| stealth/space-bunny-alpha | — | closed resolved | Removed the obsolete snapd-snap setting in #5689 (8f02d3d48), fixing core20 builds in Snapcraft 8.12; the core18/Snapcraft 7 variant was backported by #5694 in 7.5.9. | |
| stealth/space-bunny-alpha | — | closed resolved | Fixed by merged PR #5689 (8f02d3d48), which removed the obsolete snapd-snap setting. Released in Snapcraft 8.12; backported by PR #5694 for 7.5.9. | |
| qwen/qwen3.6-35b-a3b | — | — | Fixed in Snapcraft 8.12. The failure resulted from snapd 2.68.4 removing the core.experimental.snapd-snap flag. Snapcraft now conditionally applies the flag based on the snapd version, resolving the build error for core20 and core18 environments. | |
| qwen/qwen3.6-35b-a3b | — | — | Fixed in Snapcraft 8.12. Snapd 2.68.4 removed the core.experimental.snapd-snap option, causing build failures. Snapcraft now conditionally sets the flag based on the snapd version, resolving the issue for core20 and core18 builds. | |
| qwen3.6-35b-a3b-mtp-q6 | — | — | Fixed in Snapcraft 8.12. The build now conditionally sets the core.experimental.snapd-snap flag only when snapd is below version 2.68.4, resolving the unsupported system option error. |
Update history
No update history recorded yet.
Related work
-
Likely Fixed By:
canonical/snapcraft#5689
(confidence 99%)
Merged as commit 8f02d3d48, removing the unnecessary snapd_snap flag.
-
Related To:
canonical/snapcraft#5693
(confidence 99%)
Core18 and Snapcraft 7 counterpart; fixed by backport #5694 in Snapcraft 7.5.9.
-
Related To:
canonical/snapcraft#5694
(confidence 98%)
Backport removing the obsolete setting for Snapcraft 7.
Related issues
| Issue | Project | State | Summary | Similarity |
|---|---|---|---|---|
| #5693 Snapd error `cannot set "core.experimental.snapd-snap"` when repacking a core18 snap | snapcraft | closed | Fixed by merged backport PR #5694 (cb5283b6a), which removed the obsolete snapd-snap setting; released in Snapcraft 7.5.9. | |
| #5003 Building snap with `core20` failed with non-informative error message | snapcraft | open | The misleading core20 snapcraft-pack error was fixed by merged PR #5616 (commit b511004af), which ran the lifecycle for legacy core20 snaps. | |
| #1866300 snapcraft fails to build core20 snap | snapcraft (launchpad) | closed | Closed without a documented fix after core20 Multipass/LXD failures; core20 build-base support was unavailable and the workaround was destructive mode. | |
| #5694 fix(backport): remove unnecessary snapd_snap flag (#5689) | snapcraft | merged | Merged backport #5694 (cb5283b6a) removed obsolete snapd_snap handling for Snapcraft 7.5, fixing core20 repacking failure #5316; original fix was #5689. |