User specific font configuration does not survive snap updates

Metadata

Project: snapcraft (launchpad)
Number: #1948980
Type: issue
State: open
Author: ~gunnarhj
Labels: —
Created: 2021-10-27 07:17 PM UTC
Updated: 2021-11-17 09:35 AM UTC
Closed: —

Current evaluation

User fontconfig settings in ~/.config/fontconfig are ignored by Firefox/Chromium snaps and wiped on updates due to snapd's per-revision home directory. Open ~4.8 years, no labels, no maintainer response.

Suggested action: needs triage

Reason: The issue has no labels, zero comments, and no assignee, showing it was never triaged or categorised. It is very old (last activity 1748 days ago), but close_stale is not justified because there is no evidence the per-revision home directory behaviour in snapd has changed, so the problem likely still applies. A maintainer needs to assess whether this belongs in snapd rather than snapcraft, since the fix would be in the snap runtime, not the build tool.

Impact: 45 Quick Win: 11.25 Staleness: 88 Complexity: 75 Confidence: 70 Support Request: 10

Issue body

After the merge of <https://github.com/snapcore/snapcraft/pull/3586>, the Firefox snap will hopefully soon see files in the /etc/fonts/conf.d directory. That directory basically consists of files (or symlinks) provided by packages installed on the host system. While it's possible for a user with admin privileges to add their own fontconfig config files to that directory, the natural place for user specific font configuration is $HOME. The user equivalent of /etc/fonts/conf.d is ~/.config/fontconfig/conf.d . fontconfig reads files in that directory as well as the file ~/.config/fontconfig/fonts.conf . But the instance of fontconfig used by the Firefox snap does not. Even if you can edit ~/snap/firefox/current/.config/fontconfig/fonts.conf or put files in ~/snap/firefox/current/.config/fontconfig/conf.d, your changes will be ignored as soon as the Firefox snap gets updated. This is an Ask Ubuntu question which points at the problem: https://askubuntu.com/questions/1368185/fontconfig-that-survives-firefox-snap-updates So we would need a way to make user specific font configuration persistent. While I wrote this bug with the Firefox snap in mind (since it has replaced the .deb by default in Ubuntu 21.10), I suppose this issue is a general snap issue. As an example it was mentioned for the Chromium snap at <https://forum.snapcraft.io/t/snap-package-cannot-read-fonts-conf/16657>.

Evaluation history

Date	Model	Scores	Action	Summary
2026-09-01 09:30 AM UTC	qwen/qwen3.8-27b	Impact: 45 Quick Win: 11.25 Staleness: 88 Complexity: 75 Confidence: 70 Support Request: 10	needs triage	User fontconfig settings in ~/.config/fontconfig are ignored by Firefox/Chromium snaps and wiped on updates due to snapd's per-revision home directory. Open ~4.8 years, no labels, no maintainer response.
2026-07-23 02:11 PM UTC	qwen/qwen3.6-35b-a3b	Staleness: 95 Complexity: 70 Confidence: 80 Support Request: 10	close stale	User-specific fontconfig settings in ~/.config/fontconfig are ignored by Firefox and Chromium snaps, resetting on updates. The issue is over 4.5 years old with zero maintainer response or activity.
2026-07-22 02:45 PM UTC	qwen/qwen3.6-35b-a3b	Staleness: 95 Complexity: 60 Confidence: 85 Support Request: 10	close stale	User-specific fontconfig settings are ignored by the Firefox snap and lost on updates. The issue highlights a broader snap confinement limitation regarding persistent user configuration paths.
2026-07-10 06:04 AM UTC	qwen3.6-35b-a3b-mtp-q6	Staleness: 98 Complexity: 65 Confidence: 85 Support Request: 15	close stale	User-specific fontconfig settings in ~/.config/fontconfig/ are ignored by Firefox and other snaps, as changes in ~/snap/... are overwritten during updates. The issue highlights a persistence gap for user font configurations across snap revisions.
2026-06-21 08:35 PM UTC	qwen3.6-35b-a3b-mtp-q6	Staleness: 95 Complexity: 60 Confidence: 85 Support Request: 10	close stale	User-specific fontconfig settings are ignored by snaps because updates overwrite revision-specific paths. The report requests a persistent configuration mechanism but has had no maintainer activity in over 4.5 years.

Update history

No update history recorded yet.

Related work

Related To: snapcore/snapcraft#3586 (confidence 75%)
PR explicitly cited in the issue body as the merge that added fontconfig files to the Firefox snap, which surfaced this user-config persistence problem.

Related issues

No related issues found above the similarity threshold.