Themes apply non-existent Yaru variants and invalid accent-color (Ubuntu 26.04)

[AdrianRiao]

NOTE: Tested only on Ubuntu 26.04, but the bug is very likely broader

I'm aware Omakub is officially tested on Ubuntu 24.04 LTS and that 26.04 is out of scope for this project. I'm reporting from a 26.04 install because that's where I hit the problem, but I have good reason to believe at least the icon-rendering symptom also
affects 24.04:

• Yaru-green, Yaru-orange, Yaru-grey are not present in any version of the yaru-theme-icon package that I could find on packages.ubuntu.com. They appear to be names that have never existed in the official Yaru icon set, so osaka-jade, matte-black
  and ristretto would be broken on 24.04 as well.
• Yaru-bark does exist in yaru-theme-icon on Noble (24.04) but not on Resolute (26.04), so everforest is the one theme that may regress specifically with the version bump.
• The accent-color symptom is GNOME 47+ only, so it would not reproduce on 24.04 (which ships GNOME 46) — but it would on any distro shipping GNOME 47 or newer.

A confirmation (or refutation) from someone on a stock 24.04 install for the osaka-jade / matte-black / ristretto icon rendering would help narrow the scope. Either way, the underlying coupling (Omakub assumes every $OMAKUB_THEME_COLOR maps to a real Yaru
variant) is fragile and worth fixing regardless of the target Ubuntu version.

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Summary

On Ubuntu 26.04 with GNOME Shell 50.1, several Omakub themes silently fail to apply correctly. They reference Yaru icon/GTK variants that don't exist in the system and accent-color values outside the GNOME enum.

Concretely, 4 of 10 themes break icon rendering (Yaru-green, Yaru-orange, Yaru-grey, Yaru-bark are not packaged), and 5 of 10 themes leave accent-color unchanged between theme switches because the assigned value is rejected by GSettings and the
error is swallowed.

Only 4 of 10 themes (kanagawa, nord, rose-pine, tokyo-night) work end-to-end on a stock Ubuntu 26.04 install.

Environment

• Ubuntu 26.04 LTS (Resolute Raccoon)
• GNOME Shell 50.1
• yaru-theme-icon 26.04.5.1ubuntu (from universe)
• Omakub stable, current HEAD 68a7d00

Symptoms

Missing icons after theme switch

Applications using icons from the active GTK/icon theme render some icons blank or fall back to wrong icons. The most visible case is GNOME Calls, where the navigation tabs (recents / contacts / dialpad) appear empty. Cause: org.gnome.desktop.interface.icon-theme
points to a directory that doesn't exist in /usr/share/icons/, so GTK falls back to hicolor, which doesn't carry most of the symbolic icons apps request.

accent-color stuck on previous value

The top-right Quick Settings panel and the Alt+Esc window selection border keep the color of the previously applied theme. The new accent-color is never applied.

Root cause

themes/set-gnome-theme.sh concatenates $OMAKUB_THEME_COLOR blindly:

gsettings set org.gnome.desktop.interface gtk-theme "Yaru-$OMAKUB_THEME_COLOR-dark"
gsettings set org.gnome.desktop.interface icon-theme "Yaru-$OMAKUB_THEME_COLOR"
gsettings set org.gnome.desktop.interface accent-color "$OMAKUB_THEME_COLOR" 2>/dev/null || true

Two assumptions that don't hold on Ubuntu 26.04:

1. Every $OMAKUB_THEME_COLOR has a corresponding Yaru-<color> directory in /usr/share/icons/ and /usr/share/themes/. Not true for green, orange, grey, bark.
2. $OMAKUB_THEME_COLOR is a valid value for org.gnome.desktop.interface.accent-color. Not true: GNOME 47+ restricts this key to a closed enum, and the 2>/dev/null || true silently swallows the rejection for any non-conforming value.

Reference: valid values on Ubuntu 26.04

Yaru variants actually installed by yaru-theme-icon / yaru-theme-gtk:

Yaru, Yaru-dark, Yaru-blue(-dark), Yaru-magenta(-dark),
Yaru-olive(-dark), Yaru-prussiangreen(-dark), Yaru-purple(-dark),
Yaru-red(-dark), Yaru-sage(-dark), Yaru-wartybrown(-dark),
Yaru-yellow(-dark)

accent-color enum (from gsettings range org.gnome.desktop.interface accent-color):

blue, teal, green, yellow, orange, red, pink, purple, slate, brown

Per-theme audit

Theme	OMAKUB_THEME_COLOR	Yaru variant exists	Valid accent-color
catppuccin	magenta	yes	no
everforest	bark	no	no
gruvbox	sage	yes	no
kanagawa	purple	yes	yes
matte-black	orange	no	yes
nord	blue	yes	yes
osaka-jade	green	no	yes
ristretto	grey	no	no
rose-pine	red	yes	yes
tokyo-night	purple	yes	yes

Reproduction

omakub theme set osaka-jade   # or any of the affected themes
gsettings get org.gnome.desktop.interface icon-theme
# => 'Yaru-green'   ← directory does not exist under /usr/share/icons/
ls /usr/share/icons/Yaru-green
# => No such file or directory

gsettings get org.gnome.desktop.interface accent-color
# => previous theme's accent, unchanged

Proposed fix

Three options, in order of cleanliness:

1. Decouple OMAKUB_THEME_COLOR from the GNOME accent value by introducing a separate OMAKUB_GNOME_ACCENT variable per theme. Each theme's gnome.sh would set both. set-gnome-theme.sh consumes both, applying the Yaru color to gtk-theme/icon-theme and
   the GNOME enum value to accent-color. Cleanest separation of concerns; no implicit mapping table.
2. Map OMAKUB_THEME_COLOR to the closest GNOME accent in set-gnome-theme.sh via a small case statement (e.g. magenta → pink, sage → green, prussiangreen → green, wartybrown → brown, olive → green). Less invasive but couples the central script with
   a mapping table.
3. Per-theme override in each themes/<theme>/gnome.sh, adding an explicit gsettings set ... accent-color "<value>" after sourcing set-gnome-theme.sh, and updating OMAKUB_THEME_COLOR to an existing Yaru variant. This is the workaround I'm using locally.

Regardless of which option is picked, the 2>/dev/null || true on the accent-color line should be removed once the value is guaranteed to be valid — silent failure is what masked this bug for so long. Validating the target Yaru directory exists before calling
gsettings set for gtk-theme/icon-theme would also surface future drift between Omakub and the Yaru package.

Workaround for users hitting this today

Quick patch using option 3. Edit ~/.local/share/omakub/themes/<theme>/gnome.sh:

Theme	OMAKUB_THEME_COLOR →	Add line accent-color
catppuccin	(unchanged: magenta)	pink
everforest	olive	green
gruvbox	(unchanged: sage)	green
matte-black	yellow	(already a valid enum value)
osaka-jade	prussiangreen	green
ristretto	wartybrown	brown

Re-apply the theme with omakub theme set <theme> after editing.

[Kasui92]

Right now, Omakub doesn’t support Ubuntu 26.04 until this is merged... and even then, there’s no fallback mechanism for icons or accent colors, because the expectation is that 24.04 will remain supported.

It would need some further investigation.