Snapd error `cannot set "core.experimental.snapd-snap"` when repacking a core18 snap
Metadata
Current evaluation
Fixed by merged backport PR #5694 (cb5283b6a), which removed the obsolete snapd-snap setting; released in Snapcraft 7.5.9.
Resolution: closed resolved
Reason: Merged PR #5694, commit cb5283b6a, removed the unnecessary snapd_snap flag that triggered the unsupported core.experimental.snapd-snap error. The fix was released in Snapcraft 7.5.9.
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 | Fixed by merged backport PR #5694 (cb5283b6a), which removed the obsolete snapd-snap setting; released in Snapcraft 7.5.9. | |
| stealth/space-bunny-alpha | — | closed resolved | Duplicate of #5316. Removing the obsolete snapd_snap flag (PR #5689, commit 8f02d3d48) fixed it; backport PR #5694 landed for the 7.5 branch. Ships in Snapcraft 7.5.9. | |
| stealth/space-bunny-alpha | — | closed resolved | Fixed core18 repacking by merged backport PR #5694, removing the unnecessary snapd_snap flag; slated for release in Snapcraft 7.5.9. | |
| qwen/qwen3.6-35b-a3b | — | — | Fixed in PR #5694 and released in Snapcraft 7.5.9. Resolves a snapd error that failed on subsequent core18 LXD builds by correcting the experimental snapd-snap system option handling. | |
| qwen/qwen3.6-35b-a3b | — | — | Fixed in PR #5694 and released in Snapcraft 7.5.9. Resolved a snapd error that occurred when rebuilding core18 snaps on a second run by correcting the unsupported experimental system option configuration. | |
| qwen/qwen3.6-35b-a3b | — | — | Fixed a snapd error preventing repeated core18 snap builds. The change was merged in pull request #5694 and shipped in Snapcraft 7.5.9. | |
| qwen3.6-35b-a3b-mtp-q6 | — | — | Fixed in PR #5694 and released in Snapcraft 7.5.9. Resolves a duplicate bug where repacking a core18 snap twice triggered a snapd error when setting an unsupported experimental option. |
Update history
No update history recorded yet.
Related work
-
Likely Fixed By:
canonical/snapcraft#5694
(confidence 100%)
Merged Snapcraft 7.5 backport that removed the snapd_snap flag.
-
Duplicate Of:
canonical/snapcraft#5316
(confidence 100%)
The maintainer explicitly identified this core18 report as a duplicate, with the same Snapd configuration error.
-
Related To:
canonical/snapcraft#5689
(confidence 95%)
Original fix for the duplicate issue, later backported for Snapcraft 7 by #5694.
Related issues
| Issue | Project | State | Summary | Similarity |
|---|---|---|---|---|
| #5316 Snapd error `cannot set "core.experimental.snapd-snap"` when repacking a core20 snap | snapcraft | closed | Snapcraft stopped setting the removed snapd option in #5689 (8f02d3d48), fixing core20 builds in Snapcraft 8.12. | |
| #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. | |
| #2444 snap: move to core18 | snapcraft | closed | Superseded by merged PR #2712, which moved Snapcraft's snap from core to core18 in commit bd5be51a3. | |
| #1886130 snapd snap not being pulled as prereq of core18 snap if core snap is installed first | snapcraft (launchpad) | closed | Closed Wont Fix (2020-07-07) by ~anonymouse67: not having the snapd snap is expected when the core snap is installed, as snapd re-execs via core; users should use classic, not devmode confinement. | |
| #2712 snap: migrate to core18 | snapcraft | merged | Merged PR #2712 by maintainer sergiusens moved Snapcraft's own snap from base core to core18, landing as commit bd5be51a3 (8 files, +95/-42); it superseded the earlier closed attempt PR #2444. |