docs: core20->core22 migration guide should mention removing `passthrough`
Metadata
Current evaluation
Closed and assigned to a contributor for the requested documentation update. The core20 to core22 migration guide will be updated to warn against using the passthrough key for production snaps and provide the correct replacement structure.
Suggested action: —
No scores available.
Issue body
### Check existing issues
- [x] I've verified that this request isn't described by any existing issues.
### Request
The `passthrough` key was historically used for rapid development between snapcraft and snapd. Experimental data could be placed in `passthrough` and consumed by snapd, without requiring snapcraft to update its schema.
For core22 and higher, this key is flagged by review tools when uploading snaps to the store ([schema](https://git.launchpad.net/review-tools/tree/reviewtools/schemas/snap.json)). The [migration guide](https://documentation.ubuntu.com/snapcraft/stable/how-to/change-bases/change-from-core20-to-core22/) should inform users to not use it.
It should tell users to remove the `passthrough` key for production snaps. For example:
```yaml
hooks:
passthrough:
environment:
FOO: BAR
```
should become
```yaml
hooks:
environment:
FOO: BAR
```
A subsequent improvement would add a pre-lint rule for this.
### The problem it solves
To improve the docs.
source: https://chat.canonical.com/canonical/pl/6y69jfbhy7rczpj9xotbjjatdy
Evaluation history
| Date | Model | Scores | Action | Summary |
|---|---|---|---|---|
| qwen/qwen3.6-35b-a3b | — | — | Closed and assigned to a contributor for the requested documentation update. The core20 to core22 migration guide will be updated to warn against using the passthrough key for production snaps and provide the correct replacement structure. | |
| qwen/qwen3.6-35b-a3b | — | — | Closed and assigned to a contributor to update the core20-to-core22 migration guide. Documentation will explicitly warn against using the passthrough key for production snaps and show the correct replacement structure. | |
| qwen/qwen3.6-35b-a3b | — | — | The documentation update request regarding the deprecated passthrough key was assigned to a contributor and closed, pending implementation via a separate pull request. | |
| qwen3.6-35b-a3b-mtp-q6 | — | — | Closed and resolved via documentation update. A contributor volunteered to update the core20 to core22 migration guide, instructing users to remove the deprecated passthrough key for production snaps. | |
| qwen3.6-35b-a3b-mtp-q6 | — | — | Fixed by updating the core20 to core22 migration guide to warn users to remove the passthrough key and show the correct replacement structure. Assigned to a contributor for implementation. |
Update history
No update history recorded yet.
Related issues
| Issue | Project | State | Summary | Similarity |
|---|---|---|---|---|
| #6124 docs: mention removing passthrough in core20 to core22 migration | snapcraft | merged | Merged documentation update clarifying that the passthrough key must be removed for production snaps targeting core22+. Adds a migration example for hook environment data and closes issue 5986. Review comments were addressed. |