`snaphelpers` getting snap config can fail when `snapd` is unavailable`

Metadata

Project: charmcraft
Number: #921
Type: issue
State: open
Author: mr-cal
Labels: —
Created: 2022-11-04 10:16 AM UTC
Updated: 2025-08-15 03:18 PM UTC
Closed: —

Current evaluation

snaphelpers calls in charmcraft's configure hook can raise unhelpful errors when snapd is unavailable. Maintainer acknowledged as low priority (2024-08); only the configure hook still uses snaphelpers directly. Code still lacks the try/except fix.

Suggested action: keep open

Reason: Maintainer @lengau triaged this as low priority (2024-08-16), noting only the configure hook still uses snaphelpers directly. The code in charmcraft/snap.py still only catches UnknownConfigKey, not SnapCtlError/AttributeError, so the issue remains valid. It is a small, well-scoped fix that should stay open for eventual completion.

Impact: 15 Quick Win: 13.5 Staleness: 65 Complexity: 10 Confidence: 78 Support Request: 5

Issue body

This is a [suggestion](https://github.com/snapcore/snapcraft/pull/3971#pullrequestreview-1165612553) from @cmatsuoka to port some error handling from snapcraft to charmcraft: When charmcraft uses the `snaphelpers` library calls to fetch the snap config (e.g. `snap get charmcraft`), it can raise an `AttributeError` or `snaphelpers.SnapCtlError` if `snapd` is unavailable. The error messages are very unhelpful. Snapcraft solved this by wrapping the `snaphelpers` calls in a try/except block and a better error message ([source](https://github.com/snapcore/snapcraft/blob/main/snapcraft/snap_config.py))

Evaluation history

Date	Model	Scores	Action	Summary
2026-09-01 12:44 AM UTC	qwen/qwen3.8-27b	Impact: 15 Quick Win: 13.5 Staleness: 65 Complexity: 10 Confidence: 78 Support Request: 5	keep open	snaphelpers calls in charmcraft's configure hook can raise unhelpful errors when snapd is unavailable. Maintainer acknowledged as low priority (2024-08); only the configure hook still uses snaphelpers directly. Code still lacks the try/except fix.
2026-07-22 11:48 AM UTC	qwen/qwen3.6-35b-a3b	Staleness: 90 Complexity: 20 Confidence: 85 Support Request: 10	close stale	Suggestion to improve error handling for snaphelpers snap config calls when snapd is unavailable. Marked low priority by a maintainer as the affected code path is now largely obsolete due to architectural changes.
2026-07-08 12:13 AM UTC	qwen3.6-35b-a3b-mtp-q6	Staleness: 85 Complexity: 15 Confidence: 90 Support Request: 10	close stale	Suggestion to improve error handling for snaphelpers snap config calls when snapd is unavailable. Marked low priority by a maintainer as direct usage is now limited to the configure script, with other paths handled by craft-application.
2026-07-05 05:45 AM UTC	qwen3.6-35b-a3b-mtp-q6	Staleness: 92 Complexity: 18 Confidence: 85 Support Request: 10	close stale	Suggestion to improve error handling for snaphelpers when snapd is unavailable. Maintainer marked it low priority, noting direct usage is now limited to a configure script and abstracted via craft-application.
2026-06-16 03:14 AM UTC	qwen3.6-35b-a3b-mtp-q6	Staleness: 85 Complexity: 20 Confidence: 75 Support Request: 10	close stale	Improve error handling for snaphelpers snap config calls when snapd is unavailable. Currently low priority as snaphelpers is only used in one legacy script. Internal tracking ticket CRAFT-3252 created.

Update history

No update history recorded yet.

Related work

Related To: canonical/snapcraft#3971 (confidence 90%)
Referenced in the issue body as the source of the error-handling pattern to port; that PR fixed the same class of crash in snapcraft's snap_config.py.

Related issues

No related issues found above the similarity threshold.