program/theme: Fix process invoked by systemd have no effects Even though running command manually (via terminal emulator) works, systemd service does not actually change theme. Set function succeeds, no panic, and still the actual value does not get the new value. I tried configuring dbus env vars and using `new_full` function to match function calls to `gsettings` CLI, but neither fixed the situation. I have completely no idea why changes through C API does not work.

Changes

3 changed files (+37/-31)

• programs/theme/build.zig
  • @@ -57,8 +57,6 @@
    exe.root_module.addOptions("config", config); exe.linkLibC(); - exe.linkSystemLibrary2("gobject-2.0", .{}); - exe.linkSystemLibrary2("gio-2.0", .{}); b.installArtifact(exe);
• programs/theme/src/gnome.zig
  • @@ -18,14 +18,6 @@ const std = @import("std");
    const Variant = @import("./variant.zig").Variant; - const gio = @cImport({ - @cInclude("gio/gio.h"); - }); - - const gobject = @cImport({ - @cInclude("glib-object.h"); - }); - const GnomeColorScheme = enum(c_int) { default = 0, @"prefer-dark" = 1,
  • @@ -41,33 +33,49 @@ }
    }; pub const ApplyError = error{ - FailedToWriteGSettings, + FailedToSpawnProcess, + GsettingsCommandUnexpectedlyTerminated, }; - pub fn apply(variant: Variant) ApplyError!void { + pub fn apply(allocator: std.mem.Allocator, variant: Variant) ApplyError!void { const gnome_color_scheme = GnomeColorScheme.from_variant(variant); - const gsettings = gio.g_settings_new("org.gnome.desktop.interface"); - defer gobject.g_object_unref(gsettings); - - const gsettings_wrote = gio.g_settings_set_enum( - gsettings, - "color-scheme", - @intFromEnum(gnome_color_scheme), - ); + const run_result = std.process.Child.run(.{ + .allocator = allocator, + .argv = &.{ + "gsettings", + "set", + "org.gnome.desktop.interface", + "color-scheme", + @tagName(gnome_color_scheme), + }, + }) catch |err| { + std.log.err("Failed to run gsettings command: {s}", .{@errorName(err)}); + return ApplyError.FailedToSpawnProcess; + }; + defer allocator.free(run_result.stdout); + defer allocator.free(run_result.stderr); - if (gsettings_wrote == 0) { - std.log.warn( - "Unable to set GNOME color scheme to {s}", - .{@tagName(gnome_color_scheme)}, - ); - return ApplyError.FailedToWriteGSettings; + if (run_result.stderr.len > 0) { + std.io.getStdErr().writeAll(run_result.stderr) catch {}; } - // https://docs.gtk.org/gio/class.Settings.html#delay-apply-mode - // > ...these writes may not complete by the time that g_settings_set() - // > returns; see g_settings_sync()). - gio.g_settings_sync(); + switch (run_result.term) { + .Exited => |code| { + if (code != 0) { + std.log.err("Non zero exit: {d}", .{code}); + return ApplyError.GsettingsCommandUnexpectedlyTerminated; + } + }, + .Signal => |sig| { + std.log.err("Signal ({d})", .{sig}); + return ApplyError.GsettingsCommandUnexpectedlyTerminated; + }, + else => { + std.log.err("Process terminated abnormally", .{}); + return ApplyError.GsettingsCommandUnexpectedlyTerminated; + }, + } std.log.info("Set GNOME color scheme to {s}", .{@tagName(gnome_color_scheme)}); }
• programs/theme/src/main.zig
  • @@ -85,7 +85,7 @@ std.log.err("Too many arguments.", .{});
    return ExitCode.incorrect_usage.to_u8(); } - gnome.apply(variant) catch {}; + gnome.apply(allocator, variant) catch {}; return ExitCode.ok.to_u8(); }