[Bug] Icon theme lookup fails for app_icon parameter while image-path hint works

[shayonpal]

Description

When sending notifications via notify-send --icon=ICON_NAME, SwayNC displays a fallback text symbol (ⓘ) instead of the actual icon. However, using --hint=string:image-path:/path/to/icon.png with the same icon works perfectly.

Steps to Reproduce

# This fails - shows fallback symbol
notify-send "Test" "Icon name lookup" --icon=dialog-information

# This works - shows actual icon
notify-send "Test" "Direct path" --hint=string:image-path:/usr/share/icons/Adwaita/symbolic/status/dialog-information-symbolic.svg

Expected Behavior

Both methods should display the icon. The --icon parameter should resolve the icon name via GTK4's IconTheme lookup.

Actual Behavior

• --icon=dialog-information → Shows fallback text "ⓘ"
• --hint=string:image-path:/path → Shows actual icon correctly

Investigation Results

GTK4 icon lookup works outside SwayNC

import gi
gi.require_version('Gtk', '4.0')
from gi.repository import Gtk, Gdk

display = Gdk.Display.get_default()
theme = Gtk.IconTheme.get_for_display(display)
print(theme.get_theme_name())  # Colloid-Purple-Dark
print(theme.has_icon('dialog-information'))  # True

This confirms GTK4 can find the icons correctly.

D-Bus message inspection

The notification is sent correctly:

method call ... member=Notify
   string "notify-send"
   uint32 0
   string "dialog-information"  <-- app_icon parameter
   string "Test"
   string "Icon name lookup"
   ...

Code analysis

Looking at notification.vala, the app_icon handling differs from image_path:

// For image_path - checks if it's a theme icon:
if (!img_path_exists) {
    img_path_exists = icon_theme.has_icon(param.image_path);
    img_path_is_theme_icon = img_path_exists;
}

// For app_icon - only checks if it's a file:
app_icon_exists = File.new_for_path(app_icon_uri).query_exists();
// No theme icon check here!

In functions.vala, set_image_uri does try icon lookup as fallback:

if (img.storage_type == Gtk.ImageType.EMPTY) {
    unowned Gdk.Display display = Gdk.Display.get_default();
    unowned Gtk.IconTheme icon_theme = Gtk.IconTheme.get_for_display(display);
    if (icon_theme.has_icon(uri)) {
        img.set_from_icon_name(uri);
    }
}

However, this lookup appears to fail even though identical Python code succeeds. Possible causes:

1. Gdk.Display.get_default() returns different/null display in SwayNC context
2. IconTheme instance differs between notification widget context and default display
3. Timing issue where display isn't fully initialized when lookup occurs

Workaround

Created a wrapper script that resolves icon names to paths before calling notify-send:

#!/bin/bash
# Resolve icon name to path using GTK4
icon_path=$(python3 -c "
import gi
gi.require_version('Gtk', '4.0')
from gi.repository import Gtk, Gdk
display = Gdk.Display.get_default()
theme = Gtk.IconTheme.get_for_display(display)
icon = theme.lookup_icon('$1', None, 64, 1, Gtk.TextDirection.LTR, 0)
if icon and icon.get_file():
    print(icon.get_file().get_path())
")
notify-send "Title" "Body" --hint=string:image-path:"$icon_path"

Environment

• SwayNC version: 0.12.4
• OS: Fedora Asahi Remix 42 (Linux 6.17.12)
• Desktop: Hyprland 0.53.1 (Wayland)
• GTK4 version: 4.18
• Icon theme: Colloid-Purple-Dark (also tested with Adwaita)
• Display scaling: 1.6x HiDPI

Additional Notes

• Apps that send image-data or image-path hints (like Kitty terminal) display icons correctly
• Only app_icon parameter (icon name lookup) fails
• The icon files exist and are found by GTK4 Python - only SwayNC's internal lookup fails

[ErikReider]

Strange, works on my system for some reason... I'll have to investigate this further

Edit: Could you test setting your icon theme back to "Adwaita"?