Snapd error `cannot set "core.experimental.snapd-snap"` when repacking a core18 snap
Metadata
Current evaluation
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.
Suggested action: —
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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 |
|---|---|---|---|---|
| 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. | |
| qwen3.6-35b-a3b-mtp-q6 | — | — | Fixed in PR #5694 and released in Snapcraft 7.5.9. The snapd error during repeated core18 LXD builds was resolved by correcting the unsupported experimental system option configuration. |
Update history
No update history recorded yet.
Related issues
| Issue | Project | State | Summary | Similarity |
|---|---|---|---|---|
| #5316 Snapd error `cannot set "core.experimental.snapd-snap"` when repacking a core20 snap | snapcraft | closed | 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. |