DisplaySettings: Stop using DeprecatedString

This also further improves error propagation in cases where String
demands it.

13 files changed, 217 insertions, 116 deletions

diff --git a/Userland/Applications/DisplaySettings/BackgroundSettingsWidget.cpp b/Userland/Applications/DisplaySettings/BackgroundSettingsWidget.cpp
index cd48d92011..1ceada02c9 100644
--- a/Userland/Applications/DisplaySettings/BackgroundSettingsWidget.cpp
+++ b/Userland/Applications/DisplaySettings/BackgroundSettingsWidget.cpp
@@ -34,9 +34,9 @@ ErrorOr<NonnullRefPtr<BackgroundSettingsWidget>> BackgroundSettingsWidget::try_c
 {
     auto background_settings_widget = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) BackgroundSettingsWidget(background_settings_changed)));
 
-    TRY(background_settings_widget->m_modes.try_append("Tile"));
-    TRY(background_settings_widget->m_modes.try_append("Center"));
-    TRY(background_settings_widget->m_modes.try_append("Stretch"));
+    TRY(background_settings_widget->m_modes.try_append(TRY(String::from_utf8("Tile"sv))));
+    TRY(background_settings_widget->m_modes.try_append(TRY(String::from_utf8("Center"sv))));
+    TRY(background_settings_widget->m_modes.try_append(TRY(String::from_utf8("Stretch"sv))));
 
     TRY(background_settings_widget->create_frame());
     TRY(background_settings_widget->load_current_settings());
@@ -59,12 +59,15 @@ ErrorOr<void> BackgroundSettingsWidget::create_frame()
     m_wallpaper_view->set_model(GUI::FileSystemModel::create("/res/wallpapers"));
     m_wallpaper_view->set_model_column(GUI::FileSystemModel::Column::Name);
     m_wallpaper_view->on_selection_change = [this] {
-        DeprecatedString path;
-        if (m_wallpaper_view->selection().is_empty()) {
-            path = "";
-        } else {
+        String path = String::from_utf8_short_string(""sv);
+        if (!m_wallpaper_view->selection().is_empty()) {
             auto index = m_wallpaper_view->selection().first();
-            path = static_cast<GUI::FileSystemModel*>(m_wallpaper_view->model())->full_path(index);
+            auto path_or_error = String::from_deprecated_string(static_cast<GUI::FileSystemModel*>(m_wallpaper_view->model())->full_path(index));
+            if (path_or_error.is_error()) {
+                GUI::MessageBox::show_error(window(), "Unable to load wallpaper"sv);
+                return;
+            }
+            path = path_or_error.release_value();
         }
 
         m_monitor_widget->set_wallpaper(path);
@@ -74,7 +77,7 @@ ErrorOr<void> BackgroundSettingsWidget::create_frame()
     m_context_menu = GUI::Menu::construct();
     auto const file_manager_icon = TRY(Gfx::Bitmap::load_from_file("/res/icons/16x16/app-file-manager.png"sv));
     m_show_in_file_manager_action = GUI::Action::create("Show in File Manager", file_manager_icon, [this](GUI::Action const&) {
-        LexicalPath path { m_monitor_widget->wallpaper() };
+        LexicalPath path { m_monitor_widget->wallpaper().value().to_deprecated_string() };
         Desktop::Launcher::open(URL::create_with_file_scheme(path.dirname(), path.basename()));
     });
     m_context_menu->add_action(*m_show_in_file_manager_action);
@@ -82,8 +85,9 @@ ErrorOr<void> BackgroundSettingsWidget::create_frame()
     TRY(m_context_menu->try_add_separator());
     m_copy_action = GUI::CommonActions::make_copy_action(
         [this](auto&) {
-            auto url = URL::create_with_file_scheme(m_monitor_widget->wallpaper()).to_deprecated_string();
-            GUI::Clipboard::the().set_data(url.bytes(), "text/uri-list");
+            auto wallpaper = m_monitor_widget->wallpaper();
+            if (wallpaper.has_value())
+                GUI::Clipboard::the().set_data(URL::create_with_file_scheme(wallpaper.value().to_deprecated_string()).to_deprecated_string().bytes(), "text/uri-list");
         },
         this);
     m_context_menu->add_action(*m_copy_action);
@@ -96,18 +100,23 @@ ErrorOr<void> BackgroundSettingsWidget::create_frame()
 
     auto& button = *find_descendant_of_type_named<GUI::Button>("wallpaper_open_button");
     button.on_click = [this](auto) {
-        auto path = GUI::FilePicker::get_open_filepath(window(), "Select wallpaper from file system", "/res/wallpapers"sv, false, GUI::Dialog::ScreenPosition::CenterWithinParent, { { GUI::FileTypeFilter::image_files(), GUI::FileTypeFilter::all_files() } });
-        if (!path.has_value())
+        auto path_or_empty = GUI::FilePicker::get_open_filepath(window(), "Select wallpaper from file system", "/res/wallpapers"sv, false, GUI::Dialog::ScreenPosition::CenterWithinParent, { { GUI::FileTypeFilter::image_files(), GUI::FileTypeFilter::all_files() } });
+        if (!path_or_empty.has_value())
+            return;
+        auto path = String::from_deprecated_string(path_or_empty.value());
+        if (path.is_error()) {
+            GUI::MessageBox::show_error(window(), "Unable to set wallpaper"sv);
             return;
+        }
         m_wallpaper_view->selection().clear();
-        m_monitor_widget->set_wallpaper(path.value());
+        m_monitor_widget->set_wallpaper(path.release_value());
         m_background_settings_changed = true;
         set_modified(true);
     };
 
     m_mode_combo = *find_descendant_of_type_named<GUI::ComboBox>("mode_combo");
     m_mode_combo->set_only_allow_values_from_model(true);
-    m_mode_combo->set_model(*GUI::ItemListModel<DeprecatedString>::create(m_modes));
+    m_mode_combo->set_model(*GUI::ItemListModel<String>::create(m_modes));
     bool first_mode_change = true;
     m_mode_combo->on_change = [this, first_mode_change](auto&, const GUI::ModelIndex& index) mutable {
         m_monitor_widget->set_wallpaper_mode(m_modes.at(index.row()));
@@ -134,17 +143,17 @@ ErrorOr<void> BackgroundSettingsWidget::load_current_settings()
 {
     auto ws_config = TRY(Core::ConfigFile::open("/etc/WindowServer.ini"));
 
-    auto selected_wallpaper = Config::read_string("WindowManager"sv, "Background"sv, "Wallpaper"sv, ""sv);
+    auto selected_wallpaper = TRY(String::from_deprecated_string(Config::read_string("WindowManager"sv, "Background"sv, "Wallpaper"sv, ""sv)));
     if (!selected_wallpaper.is_empty()) {
-        auto index = static_cast<GUI::FileSystemModel*>(m_wallpaper_view->model())->index(selected_wallpaper, m_wallpaper_view->model_column());
+        auto index = static_cast<GUI::FileSystemModel*>(m_wallpaper_view->model())->index(selected_wallpaper.to_deprecated_string(), m_wallpaper_view->model_column());
         m_wallpaper_view->set_cursor(index, GUI::AbstractView::SelectionUpdate::Set);
         m_monitor_widget->set_wallpaper(selected_wallpaper);
     }
 
-    auto mode = ws_config->read_entry("Background", "Mode", "Center");
+    auto mode = TRY(String::from_deprecated_string(ws_config->read_entry("Background", "Mode", "Center")));
     if (!m_modes.contains_slow(mode)) {
         warnln("Invalid background mode '{}' in WindowServer config, falling back to 'Center'", mode);
-        mode = "Center";
+        mode = TRY(String::from_utf8("Center"sv));
     }
     m_monitor_widget->set_wallpaper_mode(mode);
     m_mode_combo->set_selected_index(m_modes.find_first_index(mode).value_or(0), GUI::AllowCallback::No);
@@ -167,8 +176,19 @@ ErrorOr<void> BackgroundSettingsWidget::load_current_settings()
 
 void BackgroundSettingsWidget::apply_settings()
 {
-    if (!GUI::Desktop::the().set_wallpaper(m_monitor_widget->wallpaper_bitmap(), m_monitor_widget->wallpaper()))
-        GUI::MessageBox::show_error(window(), DeprecatedString::formatted("Unable to load file {} as wallpaper", m_monitor_widget->wallpaper()));
+    auto wallpaper_path_or_empty = m_monitor_widget->wallpaper();
+
+    if (!GUI::Desktop::the().set_wallpaper(m_monitor_widget->wallpaper_bitmap(), wallpaper_path_or_empty)) {
+        if (!wallpaper_path_or_empty.has_value()) {
+            GUI::MessageBox::show_error(window(), "Unable to load wallpaper"sv);
+        } else {
+            auto detailed_error_message = String::formatted("Unable to load file {} as wallpaper", wallpaper_path_or_empty.value());
+            if (!detailed_error_message.is_error())
+                GUI::MessageBox::show_error(window(), detailed_error_message.release_value());
+            else
+                GUI::MessageBox::show_error(window(), "Unable to load wallpaper"sv);
+        }
+    }
 
     GUI::Desktop::the().set_background_color(m_color_input->text());
     GUI::Desktop::the().set_wallpaper_mode(m_monitor_widget->wallpaper_mode());
diff --git a/Userland/Applications/DisplaySettings/BackgroundSettingsWidget.h b/Userland/Applications/DisplaySettings/BackgroundSettingsWidget.h
index fcb92ebd54..6de09c15f2 100644
--- a/Userland/Applications/DisplaySettings/BackgroundSettingsWidget.h
+++ b/Userland/Applications/DisplaySettings/BackgroundSettingsWidget.h
@@ -9,6 +9,7 @@
 #pragma once
 
 #include "MonitorWidget.h"
+#include <AK/String.h>
 #include <LibCore/Timer.h>
 #include <LibGUI/ColorInput.h>
 #include <LibGUI/ComboBox.h>
@@ -33,7 +34,7 @@ private:
     ErrorOr<void> create_frame();
     ErrorOr<void> load_current_settings();
 
-    Vector<DeprecatedString> m_modes;
+    Vector<String> m_modes;
 
     bool& m_background_settings_changed;
 
diff --git a/Userland/Applications/DisplaySettings/DesktopSettingsWidget.cpp b/Userland/Applications/DisplaySettings/DesktopSettingsWidget.cpp
index d7a4da600f..e832a5d35f 100644
--- a/Userland/Applications/DisplaySettings/DesktopSettingsWidget.cpp
+++ b/Userland/Applications/DisplaySettings/DesktopSettingsWidget.cpp
@@ -15,7 +15,8 @@
 
 namespace DisplaySettings {
 
-ErrorOr<NonnullRefPtr<DesktopSettingsWidget>> DesktopSettingsWidget::try_create() {
+ErrorOr<NonnullRefPtr<DesktopSettingsWidget>> DesktopSettingsWidget::try_create()
+{
     auto desktop_settings_widget = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) DesktopSettingsWidget()));
     TRY(desktop_settings_widget->create_frame());
     desktop_settings_widget->load_current_settings();
@@ -55,8 +56,7 @@ void DesktopSettingsWidget::apply_settings()
     auto& desktop = GUI::Desktop::the();
     if (workspace_rows != desktop.workspace_rows() || workspace_columns != desktop.workspace_columns()) {
         if (!GUI::ConnectionToWindowServer::the().apply_workspace_settings(workspace_rows, workspace_columns, true)) {
-            GUI::MessageBox::show(window(), DeprecatedString::formatted("Error applying workspace settings"),
-                "Workspace settings"sv, GUI::MessageBox::Type::Error);
+            GUI::MessageBox::show_error(window(), "Error applying workspace settings"sv);
         }
     }
 }
diff --git a/Userland/Applications/DisplaySettings/EffectsSettingsWidget.cpp b/Userland/Applications/DisplaySettings/EffectsSettingsWidget.cpp
index 1c7cfad9ac..aea56f8565 100644
--- a/Userland/Applications/DisplaySettings/EffectsSettingsWidget.cpp
+++ b/Userland/Applications/DisplaySettings/EffectsSettingsWidget.cpp
@@ -128,8 +128,8 @@ ErrorOr<void> EffectsSettingsWidget::load_settings()
         "Never"sv
     };
     for (size_t i = 0; i < list.size(); ++i)
-        TRY(m_geometry_list.try_append(list[i]));
-    m_geometry_combobox->set_model(ItemListModel<DeprecatedString>::create(m_geometry_list));
+        TRY(m_geometry_list.try_append(TRY(String::from_utf8(list[i]))));
+    m_geometry_combobox->set_model(ItemListModel<String>::create(m_geometry_list));
     m_geometry_combobox->set_selected_index(m_system_effects.geometry());
 
     return {};
diff --git a/Userland/Applications/DisplaySettings/EffectsSettingsWidget.h b/Userland/Applications/DisplaySettings/EffectsSettingsWidget.h
index d68ccaf49c..9abd977aa0 100644
--- a/Userland/Applications/DisplaySettings/EffectsSettingsWidget.h
+++ b/Userland/Applications/DisplaySettings/EffectsSettingsWidget.h
@@ -6,6 +6,7 @@
 
 #pragma once
 
+#include <AK/String.h>
 #include <LibGUI/SettingsWindow.h>
 #include <LibGUI/SystemEffects.h>
 
@@ -30,7 +31,7 @@ private:
     ErrorOr<void> load_settings();
 
     SystemEffects m_system_effects;
-    Vector<DeprecatedString> m_geometry_list;
+    Vector<String> m_geometry_list;
     RefPtr<ComboBox> m_geometry_combobox;
 };
 
diff --git a/Userland/Applications/DisplaySettings/MonitorSettingsWidget.cpp b/Userland/Applications/DisplaySettings/MonitorSettingsWidget.cpp
index 2702c7be8d..20d2a655fb 100644
--- a/Userland/Applications/DisplaySettings/MonitorSettingsWidget.cpp
+++ b/Userland/Applications/DisplaySettings/MonitorSettingsWidget.cpp
@@ -67,7 +67,7 @@ ErrorOr<void> MonitorSettingsWidget::create_resolution_list()
 
         i32 aspect_width = resolution.width() / gcf;
         i32 aspect_height = resolution.height() / gcf;
-        TRY(m_resolution_strings.try_append(DeprecatedString::formatted("{}x{} ({}:{})", resolution.width(), resolution.height(), aspect_width, aspect_height)));
+        TRY(m_resolution_strings.try_append(TRY(String::formatted("{}x{} ({}:{})", resolution.width(), resolution.height(), aspect_width, aspect_height))));
     }
 
     return {};
@@ -81,21 +81,27 @@ ErrorOr<void> MonitorSettingsWidget::create_frame()
 
     m_screen_combo = *find_descendant_of_type_named<GUI::ComboBox>("screen_combo");
     m_screen_combo->set_only_allow_values_from_model(true);
-    m_screen_combo->set_model(*GUI::ItemListModel<DeprecatedString>::create(m_screens));
+    m_screen_combo->set_model(*GUI::ItemListModel<String>::create(m_screens));
     m_screen_combo->on_change = [this](auto&, const GUI::ModelIndex& index) {
         m_selected_screen_index = index.row();
-        selected_screen_index_or_resolution_changed();
+        auto result = selected_screen_index_or_resolution_changed();
+        if (result.is_error())
+            GUI::MessageBox::show_error(window(), "Screen info could not be updated"sv);
     };
 
     m_resolution_combo = *find_descendant_of_type_named<GUI::ComboBox>("resolution_combo");
     m_resolution_combo->set_only_allow_values_from_model(true);
-    m_resolution_combo->set_model(*GUI::ItemListModel<DeprecatedString>::create(m_resolution_strings));
+    m_resolution_combo->set_model(*GUI::ItemListModel<String>::create(m_resolution_strings));
     m_resolution_combo->on_change = [this](auto&, const GUI::ModelIndex& index) {
         auto& selected_screen = m_screen_layout.screens[m_selected_screen_index];
         selected_screen.resolution = m_resolutions.at(index.row());
         // Try to auto re-arrange things if there are overlaps or disconnected screens
         m_screen_layout.normalize();
-        selected_screen_index_or_resolution_changed();
+        auto result = selected_screen_index_or_resolution_changed();
+        if (result.is_error()) {
+            GUI::MessageBox::show_error(window(), "Screen info could not be updated"sv);
+            return;
+        }
         set_modified(true);
     };
 
@@ -129,20 +135,20 @@ ErrorOr<void> MonitorSettingsWidget::create_frame()
     return {};
 }
 
-static DeprecatedString display_name_from_edid(EDID::Parser const& edid)
+static ErrorOr<String> display_name_from_edid(EDID::Parser const& edid)
 {
     auto manufacturer_name = edid.manufacturer_name();
     auto product_name = edid.display_product_name();
 
-    auto build_manufacturer_product_name = [&]() {
+    auto build_manufacturer_product_name = [&]() -> ErrorOr<String> {
         if (product_name.is_null() || product_name.is_empty())
-            return manufacturer_name;
-        return DeprecatedString::formatted("{} {}", manufacturer_name, product_name);
+            return TRY(String::from_deprecated_string(manufacturer_name));
+        return String::formatted("{} {}", manufacturer_name, product_name);
     };
 
     if (auto screen_size = edid.screen_size(); screen_size.has_value()) {
         auto diagonal_inch = hypot(screen_size.value().horizontal_cm(), screen_size.value().vertical_cm()) / 2.54;
-        return DeprecatedString::formatted("{} {}\"", build_manufacturer_product_name(), roundf(diagonal_inch));
+        return String::formatted("{} {}\"", TRY(build_manufacturer_product_name()), roundf(diagonal_inch));
     }
 
     return build_manufacturer_product_name();
@@ -157,34 +163,34 @@ ErrorOr<void> MonitorSettingsWidget::load_current_settings()
 
     size_t virtual_screen_count = 0;
     for (size_t i = 0; i < m_screen_layout.screens.size(); i++) {
-        DeprecatedString screen_display_name;
+        String screen_display_name;
         if (m_screen_layout.screens[i].mode == WindowServer::ScreenLayout::Screen::Mode::Device) {
             if (auto edid = EDID::Parser::from_display_connector_device(m_screen_layout.screens[i].device.value()); !edid.is_error()) { // TODO: multihead
-                screen_display_name = display_name_from_edid(edid.value());
+                screen_display_name = TRY(display_name_from_edid(edid.value()));
                 TRY(m_screen_edids.try_append(edid.release_value()));
             } else {
                 dbgln("Error getting EDID from device {}: {}", m_screen_layout.screens[i].device.value(), edid.error());
-                screen_display_name = m_screen_layout.screens[i].device.value();
+                screen_display_name = TRY(String::from_deprecated_string(m_screen_layout.screens[i].device.value()));
                 TRY(m_screen_edids.try_append({}));
             }
         } else {
             dbgln("Frame buffer {} is virtual.", i);
-            screen_display_name = DeprecatedString::formatted("Virtual screen {}", virtual_screen_count++);
+            screen_display_name = TRY(String::formatted("Virtual screen {}", virtual_screen_count++));
             TRY(m_screen_edids.try_append({}));
         }
         if (i == m_screen_layout.main_screen_index)
-            TRY(m_screens.try_append(DeprecatedString::formatted("{}: {} (main screen)", i + 1, screen_display_name)));
+            TRY(m_screens.try_append(TRY(String::formatted("{}: {} (main screen)", i + 1, screen_display_name))));
         else
-            TRY(m_screens.try_append(DeprecatedString::formatted("{}: {}", i + 1, screen_display_name)));
+            TRY(m_screens.try_append(TRY(String::formatted("{}: {}", i + 1, screen_display_name))));
     }
     m_selected_screen_index = m_screen_layout.main_screen_index;
     m_screen_combo->set_selected_index(m_selected_screen_index);
-    selected_screen_index_or_resolution_changed();
+    TRY(selected_screen_index_or_resolution_changed());
 
     return {};
 }
 
-void MonitorSettingsWidget::selected_screen_index_or_resolution_changed()
+ErrorOr<void> MonitorSettingsWidget::selected_screen_index_or_resolution_changed()
 {
     auto& screen = m_screen_layout.screens[m_selected_screen_index];
 
@@ -193,7 +199,7 @@ void MonitorSettingsWidget::selected_screen_index_or_resolution_changed()
     Gfx::IntSize current_resolution = m_resolutions.at(index);
 
     Optional<unsigned> screen_dpi;
-    DeprecatedString screen_dpi_tooltip;
+    String screen_dpi_tooltip;
     if (m_screen_edids[m_selected_screen_index].has_value()) {
         auto& edid = m_screen_edids[m_selected_screen_index];
         if (auto screen_size = edid.value().screen_size(); screen_size.has_value()) {
@@ -203,14 +209,15 @@ void MonitorSettingsWidget::selected_screen_index_or_resolution_changed()
             auto diagonal_pixels = hypot(current_resolution.width(), current_resolution.height());
             if (diagonal_pixels != 0.0) {
                 screen_dpi = diagonal_pixels / diagonal_inch;
-                screen_dpi_tooltip = DeprecatedString::formatted("{} inch display ({}cm x {}cm)", roundf(diagonal_inch), x_cm, y_cm);
+                screen_dpi_tooltip = TRY(String::formatted("{} inch display ({}cm x {}cm)", roundf(diagonal_inch), x_cm, y_cm));
             }
         }
     }
 
-    if (screen_dpi.has_value()) {
-        m_dpi_label->set_tooltip(screen_dpi_tooltip);
-        m_dpi_label->set_text(DeprecatedString::formatted("{} dpi", screen_dpi.value()));
+    auto dpi_label_value = String::formatted("{} dpi", screen_dpi.value());
+    if (screen_dpi.has_value() && !dpi_label_value.is_error()) {
+        m_dpi_label->set_tooltip(screen_dpi_tooltip.to_deprecated_string());
+        m_dpi_label->set_text(dpi_label_value.release_value().to_deprecated_string());
         m_dpi_label->set_visible(true);
     } else {
         m_dpi_label->set_visible(false);
@@ -228,6 +235,8 @@ void MonitorSettingsWidget::selected_screen_index_or_resolution_changed()
     m_resolution_combo->set_selected_index(index, GUI::AllowCallback::No);
 
     m_monitor_widget->update();
+
+    return {};
 }
 
 void MonitorSettingsWidget::apply_settings()
@@ -241,42 +250,73 @@ void MonitorSettingsWidget::apply_settings()
         if (result.success() && !load_current_settings().is_error()) {
             auto seconds_until_revert = 10;
 
-            auto box_text = [&seconds_until_revert] {
-                return DeprecatedString::formatted("Do you want to keep the new settings? They will be reverted after {} {}.",
+            auto box_text = [this, &seconds_until_revert]() -> ErrorOr<String> {
+                auto output = String::formatted("Do you want to keep the new settings? They will be reverted after {} {}.",
                     seconds_until_revert, seconds_until_revert == 1 ? "second" : "seconds");
+                if (output.is_error()) {
+                    GUI::MessageBox::show_error(window(), "Unable to apply changes"sv);
+                    return Error::from_string_literal("Unable to create a formatted string");
+                }
+                return output.release_value();
             };
 
-            auto box = GUI::MessageBox::construct(window(), box_text(), "Apply new screen layout"sv,
+            auto current_box_text_or_error = box_text();
+            if (current_box_text_or_error.is_error())
+                return;
+            auto current_box_text = current_box_text_or_error.release_value();
+
+            auto box = GUI::MessageBox::construct(window(), current_box_text, "Apply new screen layout"sv,
                 GUI::MessageBox::Type::Question, GUI::MessageBox::InputType::YesNo);
             box->set_icon(window()->icon());
 
             // If after 10 seconds the user doesn't close the message box, just close it.
-            auto revert_timer = Core::Timer::create_repeating(1000, [&] {
+            auto revert_timer_or_error = Core::Timer::create_repeating(1000, [&] {
                 seconds_until_revert -= 1;
-                box->set_text(box_text());
+                current_box_text_or_error = box_text();
+                if (current_box_text_or_error.is_error()) {
+                    seconds_until_revert = 0;
+                    box->close();
+                    return;
+                }
+                auto current_box_text = current_box_text_or_error.release_value();
+                box->set_text(current_box_text.to_deprecated_string());
                 if (seconds_until_revert <= 0) {
                     box->close();
                 }
-            }).release_value_but_fixme_should_propagate_errors();
+            });
+            if (revert_timer_or_error.is_error()) {
+                GUI::MessageBox::show_error(window(), "Unable to apply changes"sv);
+                return;
+            }
+            auto revert_timer = revert_timer_or_error.release_value();
             revert_timer->start();
 
             // If the user selects "No", closes the window or the window gets closed by the 10 seconds timer, revert the changes.
             if (box->exec() == GUI::MessageBox::ExecResult::Yes) {
                 auto save_result = GUI::ConnectionToWindowServer::the().save_screen_layout();
                 if (!save_result.success()) {
-                    GUI::MessageBox::show(window(), DeprecatedString::formatted("Error saving settings: {}", save_result.error_msg()),
-                        "Unable to save setting"sv, GUI::MessageBox::Type::Error);
+                    auto detailed_error_message = String::formatted("Error saving settings: {}", save_result.error_msg());
+                    if (!detailed_error_message.is_error())
+                        GUI::MessageBox::show_error(window(), detailed_error_message.release_value());
+                    else
+                        GUI::MessageBox::show_error(window(), "Unable to save settings"sv);
                 }
             } else {
                 auto restore_result = GUI::ConnectionToWindowServer::the().set_screen_layout(current_layout, false);
                 if (!restore_result.success() || load_current_settings().is_error()) {
-                    GUI::MessageBox::show(window(), DeprecatedString::formatted("Error restoring settings: {}", restore_result.error_msg()),
-                        "Unable to restore setting"sv, GUI::MessageBox::Type::Error);
+                    auto detailed_error_message = String::formatted("Error restoring settings: {}", restore_result.error_msg());
+                    if (!detailed_error_message.is_error())
+                        GUI::MessageBox::show_error(window(), detailed_error_message.release_value());
+                    else
+                        GUI::MessageBox::show_error(window(), "Unable to restore settings"sv);
                 }
             }
         } else {
-            GUI::MessageBox::show(window(), DeprecatedString::formatted("Error setting screen layout: {}", result.error_msg()),
-                "Unable to apply changes"sv, GUI::MessageBox::Type::Error);
+            auto detailed_error_message = String::formatted("Error setting screen layout: {}", result.error_msg());
+            if (!detailed_error_message.is_error())
+                GUI::MessageBox::show_error(window(), detailed_error_message.release_value());
+            else
+                GUI::MessageBox::show_error(window(), "Unable to set screen layout"sv);
         }
     }
 }
diff --git a/Userland/Applications/DisplaySettings/MonitorSettingsWidget.h b/Userland/Applications/DisplaySettings/MonitorSettingsWidget.h
index a7e45a6399..1c689d4892 100644
--- a/Userland/Applications/DisplaySettings/MonitorSettingsWidget.h
+++ b/Userland/Applications/DisplaySettings/MonitorSettingsWidget.h
@@ -7,6 +7,7 @@
 #pragma once
 
 #include "MonitorWidget.h"
+#include <AK/String.h>
 #include <LibCore/Timer.h>
 #include <LibEDID/EDID.h>
 #include <LibGUI/ColorInput.h>
@@ -41,15 +42,15 @@ private:
     ErrorOr<void> create_frame();
     ErrorOr<void> create_resolution_list();
     ErrorOr<void> load_current_settings();
-    void selected_screen_index_or_resolution_changed();
+    ErrorOr<void> selected_screen_index_or_resolution_changed();
 
     size_t m_selected_screen_index { 0 };
 
     WindowServer::ScreenLayout m_screen_layout;
-    Vector<DeprecatedString> m_screens;
+    Vector<String> m_screens;
     Vector<Optional<EDID::Parser>> m_screen_edids;
     Vector<Gfx::IntSize> m_resolutions;
-    Vector<DeprecatedString> m_resolution_strings;
+    Vector<String> m_resolution_strings;
 
     RefPtr<DisplaySettings::MonitorWidget> m_monitor_widget;
     RefPtr<GUI::ComboBox> m_screen_combo;
diff --git a/Userland/Applications/DisplaySettings/MonitorWidget.cpp b/Userland/Applications/DisplaySettings/MonitorWidget.cpp
index 9a9fff7e8a..7dd8c005a6 100644
--- a/Userland/Applications/DisplaySettings/MonitorWidget.cpp
+++ b/Userland/Applications/DisplaySettings/MonitorWidget.cpp
@@ -28,7 +28,7 @@ ErrorOr<NonnullRefPtr<MonitorWidget>> MonitorWidget::try_create()
     return monitor_widget;
 }
 
-bool MonitorWidget::set_wallpaper(DeprecatedString path)
+bool MonitorWidget::set_wallpaper(String path)
 {
     if (!is_different_to_current_wallpaper_path(path))
         return false;
@@ -55,19 +55,21 @@ bool MonitorWidget::set_wallpaper(DeprecatedString path)
         });
 
     if (path.is_empty())
-        m_desktop_wallpaper_path = nullptr;
+        m_desktop_wallpaper_path = OptionalNone();
     else
-        m_desktop_wallpaper_path = move(path);
+        m_desktop_wallpaper_path = path;
 
     return true;
 }
 
-StringView MonitorWidget::wallpaper() const
+Optional<StringView> MonitorWidget::wallpaper() const
 {
-    return m_desktop_wallpaper_path;
+    if (m_desktop_wallpaper_path.has_value())
+        return m_desktop_wallpaper_path->bytes_as_string_view();
+    return OptionalNone();
 }
 
-void MonitorWidget::set_wallpaper_mode(DeprecatedString mode)
+void MonitorWidget::set_wallpaper_mode(String mode)
 {
     if (m_desktop_wallpaper_mode == mode)
         return;
@@ -133,12 +135,12 @@ void MonitorWidget::redraw_desktop_if_needed()
     }
     auto scaled_bitmap = scaled_bitmap_or_error.release_value();
 
-    if (m_desktop_wallpaper_mode == "Center") {
+    if (m_desktop_wallpaper_mode == "Center"sv) {
         auto centered_rect = Gfx::IntRect({}, scaled_size).centered_within(m_desktop_bitmap->rect());
         painter.blit(centered_rect.location(), *scaled_bitmap, scaled_bitmap->rect());
-    } else if (m_desktop_wallpaper_mode == "Tile") {
+    } else if (m_desktop_wallpaper_mode == "Tile"sv) {
         painter.draw_tiled_bitmap(m_desktop_bitmap->rect(), *scaled_bitmap);
-    } else if (m_desktop_wallpaper_mode == "Stretch") {
+    } else if (m_desktop_wallpaper_mode == "Stretch"sv) {
         painter.draw_scaled_bitmap(m_desktop_bitmap->rect(), *m_wallpaper_bitmap, m_wallpaper_bitmap->rect());
     } else {
         VERIFY_NOT_REACHED();
diff --git a/Userland/Applications/DisplaySettings/MonitorWidget.h b/Userland/Applications/DisplaySettings/MonitorWidget.h
index 412b4b42d5..3586314429 100644
--- a/Userland/Applications/DisplaySettings/MonitorWidget.h
+++ b/Userland/Applications/DisplaySettings/MonitorWidget.h
@@ -6,6 +6,8 @@
 
 #pragma once
 
+#include <AK/Optional.h>
+#include <AK/String.h>
 #include <LibGUI/Widget.h>
 
 namespace DisplaySettings {
@@ -15,10 +17,10 @@ class MonitorWidget final : public GUI::Widget {
 
 public:
     static ErrorOr<NonnullRefPtr<MonitorWidget>> try_create();
-    bool set_wallpaper(DeprecatedString path);
-    StringView wallpaper() const;
+    bool set_wallpaper(String path);
+    Optional<StringView> wallpaper() const;
 
-    void set_wallpaper_mode(DeprecatedString mode);
+    void set_wallpaper_mode(String mode);
     StringView wallpaper_mode() const;
 
     RefPtr<Gfx::Bitmap> wallpaper_bitmap() const { return m_wallpaper_bitmap; }
@@ -44,16 +46,23 @@ private:
     RefPtr<Gfx::Bitmap> m_desktop_bitmap;
     bool m_desktop_dirty { true };
 
-    DeprecatedString m_desktop_wallpaper_path;
+    Optional<String> m_desktop_wallpaper_path;
     RefPtr<Gfx::Bitmap> m_wallpaper_bitmap;
-    DeprecatedString m_desktop_wallpaper_mode;
+    String m_desktop_wallpaper_mode;
     Gfx::IntSize m_desktop_resolution;
     int m_desktop_scale_factor { 1 };
     Gfx::Color m_desktop_color;
 
-    bool is_different_to_current_wallpaper_path(DeprecatedString const& path)
+    bool is_different_to_current_wallpaper_path(String const& path)
     {
-        return (!path.is_empty() && path != m_desktop_wallpaper_path) || (path.is_empty() && m_desktop_wallpaper_path != nullptr);
+        if (!m_desktop_wallpaper_path.has_value()) {
+            if (path.is_empty())
+                return false;
+            return true;
+        }
+        if (m_desktop_wallpaper_path.value() == path)
+            return false;
+        return true;
     }
 };
 
diff --git a/Userland/Applications/DisplaySettings/ThemePreviewWidget.cpp b/Userland/Applications/DisplaySettings/ThemePreviewWidget.cpp
index 7969cd7554..4adc8d0631 100644
--- a/Userland/Applications/DisplaySettings/ThemePreviewWidget.cpp
+++ b/Userland/Applications/DisplaySettings/ThemePreviewWidget.cpp
@@ -18,10 +18,10 @@ ThemePreviewWidget::ThemePreviewWidget(Gfx::Palette const& palette)
     set_fixed_size(304, 201);
 }
 
-ErrorOr<void> ThemePreviewWidget::set_theme(DeprecatedString path)
+ErrorOr<void> ThemePreviewWidget::set_theme(String path)
 {
-    auto config_file = TRY(Core::File::open(path, Core::File::OpenMode::Read));
-    TRY(set_theme_from_file(path, move(config_file)));
+    auto config_file = TRY(Core::File::open(path.to_deprecated_string(), Core::File::OpenMode::Read));
+    TRY(set_theme_from_file(path.to_deprecated_string(), move(config_file)));
     return {};
 }
 
diff --git a/Userland/Applications/DisplaySettings/ThemePreviewWidget.h b/Userland/Applications/DisplaySettings/ThemePreviewWidget.h
index 8c5207a31e..0a90940175 100644
--- a/Userland/Applications/DisplaySettings/ThemePreviewWidget.h
+++ b/Userland/Applications/DisplaySettings/ThemePreviewWidget.h
@@ -6,6 +6,7 @@
 
 #pragma once
 
+#include <AK/String.h>
 #include <LibGUI/AbstractThemePreview.h>
 #include <LibGUI/Widget.h>
 #include <LibGfx/Bitmap.h>
@@ -18,7 +19,7 @@ class ThemePreviewWidget final : public GUI::AbstractThemePreview {
     C_OBJECT(ThemePreviewWidget);
 
 public:
-    ErrorOr<void> set_theme(DeprecatedString path);
+    ErrorOr<void> set_theme(String path);
 
 private:
     explicit ThemePreviewWidget(Gfx::Palette const& palette);
diff --git a/Userland/Applications/DisplaySettings/ThemesSettingsWidget.cpp b/Userland/Applications/DisplaySettings/ThemesSettingsWidget.cpp
index 4ca86602b7..d0e28f7053 100644
--- a/Userland/Applications/DisplaySettings/ThemesSettingsWidget.cpp
+++ b/Userland/Applications/DisplaySettings/ThemesSettingsWidget.cpp
@@ -19,12 +19,13 @@
 
 namespace DisplaySettings {
 
-static DeprecatedString get_color_scheme_name_from_pathname(DeprecatedString const& color_scheme_path)
+static ErrorOr<String> get_color_scheme_name_from_pathname(StringView color_scheme_path)
 {
-    return color_scheme_path.replace("/res/color-schemes/"sv, ""sv, ReplaceMode::FirstOnly).replace(".ini"sv, ""sv, ReplaceMode::FirstOnly);
+    return TRY(String::from_deprecated_string(color_scheme_path.replace("/res/color-schemes/"sv, ""sv, ReplaceMode::FirstOnly).replace(".ini"sv, ""sv, ReplaceMode::FirstOnly)));
 };
 
-ErrorOr<NonnullRefPtr<ThemesSettingsWidget>> ThemesSettingsWidget::try_create(bool& background_settings_changed) {
+ErrorOr<NonnullRefPtr<ThemesSettingsWidget>> ThemesSettingsWidget::try_create(bool& background_settings_changed)
+{
     auto theme_settings_widget = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) ThemesSettingsWidget(background_settings_changed)));
     TRY(theme_settings_widget->load_from_gml(themes_settings_gml));
     TRY(theme_settings_widget->setup_interface());
@@ -32,14 +33,15 @@ ErrorOr<NonnullRefPtr<ThemesSettingsWidget>> ThemesSettingsWidget::try_create(bo
     return theme_settings_widget;
 }
 
-ErrorOr<void> ThemesSettingsWidget::setup_interface() {
+ErrorOr<void> ThemesSettingsWidget::setup_interface()
+{
     m_themes = TRY(Gfx::list_installed_system_themes());
 
     size_t current_theme_index;
     auto current_theme_name = GUI::ConnectionToWindowServer::the().get_system_theme();
     TRY(m_theme_names.try_ensure_capacity(m_themes.size()));
     for (auto& theme_meta : m_themes) {
-        m_theme_names.append(theme_meta.name);
+        TRY(m_theme_names.try_append(TRY(String::from_deprecated_string(theme_meta.name))));
         if (current_theme_name == theme_meta.name) {
             m_selected_theme = &theme_meta;
             current_theme_index = m_theme_names.size() - 1;
@@ -49,12 +51,20 @@ ErrorOr<void> ThemesSettingsWidget::setup_interface() {
     m_theme_preview = find_descendant_of_type_named<GUI::Frame>("preview_frame")->add<ThemePreviewWidget>(palette());
     m_themes_combo = *find_descendant_of_type_named<GUI::ComboBox>("themes_combo");
     m_themes_combo->set_only_allow_values_from_model(true);
-    m_themes_combo->set_model(*GUI::ItemListModel<DeprecatedString>::create(m_theme_names));
+    m_themes_combo->set_model(*GUI::ItemListModel<String>::create(m_theme_names));
     m_themes_combo->on_change = [this](auto&, const GUI::ModelIndex& index) {
         m_selected_theme = &m_themes.at(index.row());
-        auto set_theme_result = m_theme_preview->set_theme(m_selected_theme->path);
+        auto selected_theme_path = String::from_deprecated_string(m_selected_theme->path);
+        ErrorOr<void> set_theme_result;
+        if (!selected_theme_path.is_error())
+            set_theme_result = m_theme_preview->set_theme(selected_theme_path.release_value());
         if (set_theme_result.is_error()) {
-            GUI::MessageBox::show_error(window(), DeprecatedString::formatted("There was an error generating the theme preview: {}", set_theme_result.error()));
+            auto detailed_error_message = String::formatted("There was an error generating the theme preview: {}", set_theme_result.error());
+            if (!detailed_error_message.is_error())
+                GUI::MessageBox::show_error(window(), detailed_error_message.release_value());
+            else
+                GUI::MessageBox::show_error(window(), "There was an error generating the theme preview"sv);
+            return;
         }
         set_modified(true);
     };
@@ -66,13 +76,13 @@ ErrorOr<void> ThemesSettingsWidget::setup_interface() {
     Core::DirIterator iterator("/res/color-schemes", Core::DirIterator::SkipParentAndBaseDir);
     while (iterator.has_next()) {
         auto path = iterator.next_path();
-        m_color_scheme_names.append(path.replace(".ini"sv, ""sv, ReplaceMode::FirstOnly));
+        TRY(m_color_scheme_names.try_append(TRY(String::from_deprecated_string(path.replace(".ini"sv, ""sv, ReplaceMode::FirstOnly)))));
     }
     quick_sort(m_color_scheme_names);
     auto& color_scheme_combo = *find_descendant_of_type_named<GUI::ComboBox>("color_scheme_combo");
     color_scheme_combo.set_only_allow_values_from_model(true);
-    color_scheme_combo.set_model(*GUI::ItemListModel<DeprecatedString>::create(m_color_scheme_names));
-    m_selected_color_scheme_name = get_color_scheme_name_from_pathname(GUI::Widget::palette().color_scheme_path());
+    color_scheme_combo.set_model(*GUI::ItemListModel<String>::create(m_color_scheme_names));
+    m_selected_color_scheme_name = TRY(get_color_scheme_name_from_pathname(GUI::Widget::palette().color_scheme_path()));
     auto selected_color_scheme_index = m_color_scheme_names.find_first_index(m_selected_color_scheme_name);
     if (selected_color_scheme_index.has_value())
         color_scheme_combo.set_selected_index(selected_color_scheme_index.value());
@@ -85,7 +95,10 @@ ErrorOr<void> ThemesSettingsWidget::setup_interface() {
         }
     }
     color_scheme_combo.on_change = [this](auto&, const GUI::ModelIndex& index) {
-        m_selected_color_scheme_name = index.data().as_string();
+        auto result = String::from_deprecated_string(index.data().as_string());
+        if (result.is_error())
+            return;
+        m_selected_color_scheme_name = result.release_value();
         m_color_scheme_is_file_based = true;
         set_modified(true);
     };
@@ -123,9 +136,16 @@ ErrorOr<void> ThemesSettingsWidget::setup_interface() {
             if (current_theme_name == theme_meta.name) {
                 m_themes_combo->set_selected_index(index, GUI::AllowCallback::No);
                 m_selected_theme = &m_themes.at(index);
-                auto set_theme_result = m_theme_preview->set_theme(m_selected_theme->path);
+                auto selected_theme_path = String::from_deprecated_string(m_selected_theme->path);
+                ErrorOr<void> set_theme_result;
+                if (!selected_theme_path.is_error())
+                    set_theme_result = m_theme_preview->set_theme(selected_theme_path.release_value());
                 if (set_theme_result.is_error()) {
-                    GUI::MessageBox::show_error(window(), DeprecatedString::formatted("There was an error setting the new theme: {}", set_theme_result.error()));
+                    auto detailed_error_message = String::formatted("There was an error generating the theme preview: {}", set_theme_result.error());
+                    if (!detailed_error_message.is_error())
+                        GUI::MessageBox::show_error(window(), detailed_error_message.release_value());
+                    else
+                        GUI::MessageBox::show_error(window(), "There was an error generating the theme preview"sv);
                 }
             }
             ++index;
@@ -136,36 +156,42 @@ ErrorOr<void> ThemesSettingsWidget::setup_interface() {
 }
 
 ThemesSettingsWidget::ThemesSettingsWidget(bool& background_settings_changed)
-    : m_background_settings_changed {background_settings_changed }
+    : m_background_settings_changed { background_settings_changed }
 {
 }
 
 void ThemesSettingsWidget::apply_settings()
 {
     m_background_settings_changed = false;
-    Optional<DeprecatedString> color_scheme_path = DeprecatedString::formatted("/res/color-schemes/{}.ini", m_selected_color_scheme_name);
+    auto color_scheme_path_or_error = String::formatted("/res/color-schemes/{}.ini", m_selected_color_scheme_name);
+    if (color_scheme_path_or_error.is_error()) {
+        GUI::MessageBox::show_error(window(), "Unable to apply changes"sv);
+        return;
+    }
+    auto color_scheme_path = color_scheme_path_or_error.release_value();
 
     if (!m_color_scheme_is_file_based && find_descendant_of_type_named<GUI::CheckBox>("custom_color_scheme_checkbox")->is_checked()) {
         auto set_theme_result = GUI::ConnectionToWindowServer::the().set_system_theme(m_selected_theme->path, m_selected_theme->name, m_background_settings_changed, "Custom"sv);
-        if(!set_theme_result)
+        if (!set_theme_result)
             GUI::MessageBox::show_error(window(), "Failed to apply theme settings"sv);
     } else if (find_descendant_of_type_named<GUI::CheckBox>("custom_color_scheme_checkbox")->is_checked()) {
-        auto set_theme_result = GUI::ConnectionToWindowServer::the().set_system_theme(m_selected_theme->path, m_selected_theme->name, m_background_settings_changed, color_scheme_path);
-        if(!set_theme_result)
+        auto set_theme_result = GUI::ConnectionToWindowServer::the().set_system_theme(m_selected_theme->path, m_selected_theme->name, m_background_settings_changed, color_scheme_path.to_deprecated_string());
+        if (!set_theme_result)
             GUI::MessageBox::show_error(window(), "Failed to apply theme settings"sv);
     } else {
-        auto set_theme_result = GUI::ConnectionToWindowServer::the().set_system_theme(m_selected_theme->path, m_selected_theme->name, m_background_settings_changed, OptionalNone());
-        if (!set_theme_result) {
-            GUI::MessageBox::show_error(window(), "Failed to apply theme settings"sv);
-            return;
-        }
-        // Update the color scheme combobox to match the new theme.
         auto theme_config = Core::ConfigFile::open(m_selected_theme->path);
         if (theme_config.is_error()) {
             GUI::MessageBox::show_error(window(), "Failed to open theme config file"sv);
             return;
         }
-        auto const color_scheme_index = m_color_scheme_names.find_first_index(get_color_scheme_name_from_pathname(theme_config.release_value()->read_entry("Paths", "ColorScheme")));
+        auto preferred_color_scheme_path = get_color_scheme_name_from_pathname(theme_config.release_value()->read_entry("Paths", "ColorScheme"));
+        auto set_theme_result = GUI::ConnectionToWindowServer::the().set_system_theme(m_selected_theme->path, m_selected_theme->name, m_background_settings_changed, OptionalNone());
+        if (!set_theme_result || preferred_color_scheme_path.is_error()) {
+            GUI::MessageBox::show_error(window(), "Failed to apply theme settings"sv);
+            return;
+        }
+        // Update the color scheme combobox to match the new theme.
+        auto const color_scheme_index = m_color_scheme_names.find_first_index(preferred_color_scheme_path.value());
         if (color_scheme_index.has_value())
             find_descendant_of_type_named<GUI::ComboBox>("color_scheme_combo")->set_selected_index(color_scheme_index.value());
     }
diff --git a/Userland/Applications/DisplaySettings/ThemesSettingsWidget.h b/Userland/Applications/DisplaySettings/ThemesSettingsWidget.h
index 8617aff73e..ebba4df6ff 100644
--- a/Userland/Applications/DisplaySettings/ThemesSettingsWidget.h
+++ b/Userland/Applications/DisplaySettings/ThemesSettingsWidget.h
@@ -6,7 +6,7 @@
 
 #pragma once
 
-#include <AK/DeprecatedString.h>
+#include <AK/String.h>
 #include <AK/Vector.h>
 #include <LibGUI/ComboBox.h>
 #include <LibGUI/SettingsWindow.h>
@@ -26,13 +26,13 @@ public:
 private:
     ErrorOr<void> setup_interface();
     Vector<Gfx::SystemThemeMetaData> m_themes;
-    Vector<DeprecatedString> m_theme_names;
-    Vector<DeprecatedString> m_color_scheme_names;
+    Vector<String> m_theme_names;
+    Vector<String> m_color_scheme_names;
 
     RefPtr<GUI::ComboBox> m_themes_combo;
     RefPtr<ThemePreviewWidget> m_theme_preview;
     Gfx::SystemThemeMetaData const* m_selected_theme { nullptr };
-    DeprecatedString m_selected_color_scheme_name = "";
+    String m_selected_color_scheme_name {};
 
     RefPtr<GUI::Button> m_cursor_themes_button;