[HamzaHassanM]

Summary

On modern Linux distributions such as Ubuntu 24.04 LTS, Electron Snap applications experience broken font rendering where UI text (such as system tray context menus and dialogs) renders as square boxes (tofu □□□□).

Root Cause

1. electron-builder's core22 snap launcher runs desktop-common.sh, which defines make_user_fontconfig and unconditionally emits <cachedir>$REALHOME/.cache/fontconfig</cachedir>.
2. The bundled snap runtime uses gnome-3-28-1804 (fontconfig 2.12.6, cache format 7), whereas modern host systems run fontconfig 2.15.0+ (cache format 11/12).
3. The Snap's fontconfig attempts to parse host cache files with incompatible binary formats, failing glyph resolution and falling back to tofu boxes.
4. Clearing host/snap caches manually is only a temporary workaround because the host system regenerates modern cache files as soon as fonts or packages update on the host.

Fix

• In scripts/patchSnapDesktopLauncher.js, patch desktop-common.sh at build time to remove the $REALHOME/.cache/fontconfig reference from make_user_fontconfig. The snap now strictly uses its own isolated cache path (<cachedir prefix="xdg">fontconfig</cachedir>), mapped to $SNAP_USER_COMMON/.cache/fontconfig.
• Clear stale snap font caches ($XDG_CACHE_HOME/fontconfig) when SNAP_DESKTOP_COMPONENTS_NEED_UPDATE="true" so existing installations upgrading to this revision automatically purge corrupt/incompatible cache.

closes #3092
refs #1105, #357

Testing

• npm run lint (required)
• npm run test:unit
• Ran the app manually and exercised the affected path
• Tested directly on Ubuntu 24.04 LTS: verified font cache isolation in snap and confirmed tray context menu renders correctly instead of tofu boxes.

Documentation

• Updated docs-site/docs/troubleshooting.md
• No new PII added to logs (see CLAUDE.md "Logging Guidelines")

Notes for reviewers

Unit tests were added in tests/unit/snapDesktopLauncherPatch.test.js to ensure the patch removes the host cache directory, adds the cache purge on update, and remains strictly idempotent.

Confidence Score: 5/5

The PR appears safe to merge.

Summary

The PR isolates the Snap font cache from the host cache and clears stale Snap caches on revision updates.

• Snap launches now keep font lookups inside the Snap’s own cache.

_{Reviews (3) · Last reviewed commit: "test(snap): clean up redundant inline co..." · Reviewed by Greptile}

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[Copilot]

🔵 Needs a closer look

Compatibility with downloaded architecture-specific launcher templates remains unverified.

0 open findings

What changed in this PR

Addresses square-box text in Snap menus and dialogs by isolating fontconfig caches from the host.

Changes:

• Removes host cache references and clears stale Snap caches on updates.
• Adds regression coverage for isolation, cleanup, and idempotency.
• Documents automatic isolation and older-version workarounds.

File	Description
tests/​unit/​snapDesktopLauncherPatch.test.js	Tests cache isolation, cleanup, and repeat patching.
scripts/​patchSnapDesktopLauncher.js	Patches the launcher to isolate and refresh font caches.
docs-site/​docs/​troubleshooting.md	Clarifies when manual workarounds remain necessary.

🧠 Review effort: Balanced

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📦 PR Snap Build Artifacts

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🐧 Linux Snap Packages

x86_64 (108.20 MB)

• teams-for-linux-snap-x64

arm64 (105.53 MB)

• teams-for-linux-snap-arm64

armv7l (105.27 MB)

• teams-for-linux-snap-armv7l

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📦 PR Build Artifacts

✅ Build successful! Download artifacts:

🐧 Linux

x86_64 (436.54 MB) - Contains: .deb, .rpm, .tar.gz, .AppImage

• teams-for-linux-linux-x64

arm64 (428.80 MB) - Contains: .deb, .rpm, .tar.gz, .AppImage

• teams-for-linux-linux-arm64

armv7l (430.56 MB) - Contains: .deb, .rpm, .tar.gz, .AppImage

• teams-for-linux-linux-armv7l

🍎 macOS

x86_64 (Intel) (126.01 MB) - Contains: .dmg

• teams-for-linux-macos-x64

arm64 (Apple Silicon) (119.11 MB) - Contains: .dmg

• teams-for-linux-macos-arm64

🪟 Windows

x86_64 (111.42 MB) - Contains: .exe installer

• teams-for-linux-windows-x64

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🕐 Last updated: 2026-10-15 06:42 UTC

[IsmaelMartinez]

Thanks a lot @HamzaHassanM. The squares-instead-of-text bug in the snap has come back on and off for years (#357, #865, #1105, #1328, #1336, #3092), and this is the first fix that addresses the cause rather than asking people to clear caches by hand. Running the actual launcher code under bash in the test is a nice touch. We also checked the patch against the downloaded x64 and armhf launcher templates and the bundled arm64 one, and it applies cleanly to all three. Merging.

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