LibCore+Everywhere: Return ErrorOr from ConfigFile factory methods

I've attempted to handle the errors gracefully where it was clear how to
do so, and simple, but a lot of this was just adding
`release_value_but_fixme_should_propagate_errors()` in places.

31 files changed, 77 insertions, 51 deletions

diff --git a/Meta/Lagom/Tools/ConfigureComponents/main.cpp b/Meta/Lagom/Tools/ConfigureComponents/main.cpp
index 058493666e..c09dedbe61 100644
--- a/Meta/Lagom/Tools/ConfigureComponents/main.cpp
+++ b/Meta/Lagom/Tools/ConfigureComponents/main.cpp
@@ -241,7 +241,7 @@ int main()
     }
 
     // Step 2: Open and parse the 'components.ini' file.
-    auto components_file = Core::ConfigFile::open("components.ini");
+    auto components_file = Core::ConfigFile::open("components.ini").release_value_but_fixme_should_propagate_errors();
     if (components_file->groups().is_empty()) {
         warnln("\e[31mError:\e[0m The 'components.ini' file is either not a valid ini file or contains no entries.");
         return 1;
diff --git a/Tests/LibTLS/TestTLSHandshake.cpp b/Tests/LibTLS/TestTLSHandshake.cpp
index 2784e3a151..c9bd3845a8 100644
--- a/Tests/LibTLS/TestTLSHandshake.cpp
+++ b/Tests/LibTLS/TestTLSHandshake.cpp
@@ -45,7 +45,7 @@ Vector<Certificate> load_certificates()
         return certificates;
     }
 
-    auto config = Core::ConfigFile::open(ca_certs_filepath);
+    auto config = Core::ConfigFile::open(ca_certs_filepath).release_value_but_fixme_should_propagate_errors();
     auto now = Core::DateTime::now();
     auto last_year = Core::DateTime::create(now.year() - 1);
     auto next_year = Core::DateTime::create(now.year() + 1);
diff --git a/Userland/Applications/DisplaySettings/BackgroundSettingsWidget.cpp b/Userland/Applications/DisplaySettings/BackgroundSettingsWidget.cpp
index 38bae7e44d..0a7e222cc6 100644
--- a/Userland/Applications/DisplaySettings/BackgroundSettingsWidget.cpp
+++ b/Userland/Applications/DisplaySettings/BackgroundSettingsWidget.cpp
@@ -105,7 +105,7 @@ void BackgroundSettingsWidget::create_frame()
 
 void BackgroundSettingsWidget::load_current_settings()
 {
-    auto ws_config = Core::ConfigFile::open("/etc/WindowServer.ini");
+    auto ws_config = Core::ConfigFile::open("/etc/WindowServer.ini").release_value_but_fixme_should_propagate_errors();
 
     auto selected_wallpaper = Config::read_string("WindowManager", "Background", "Wallpaper", "");
     if (!selected_wallpaper.is_empty()) {
diff --git a/Userland/Applications/KeyboardSettings/KeyboardSettingsWidget.cpp b/Userland/Applications/KeyboardSettings/KeyboardSettingsWidget.cpp
index eba887b3cc..2a697b3e15 100644
--- a/Userland/Applications/KeyboardSettings/KeyboardSettingsWidget.cpp
+++ b/Userland/Applications/KeyboardSettings/KeyboardSettingsWidget.cpp
@@ -144,7 +144,7 @@ KeyboardSettingsWidget::KeyboardSettingsWidget()
     m_current_applied_keymap = keymap_object.get("keymap").to_string();
     dbgln("KeyboardSettings thinks the current keymap is: {}", m_current_applied_keymap);
 
-    auto mapper_config(Core::ConfigFile::open("/etc/Keyboard.ini"));
+    auto mapper_config(Core::ConfigFile::open("/etc/Keyboard.ini").release_value_but_fixme_should_propagate_errors());
     auto keymaps = mapper_config->read_entry("Mapping", "Keymaps", "");
 
     auto keymaps_vector = keymaps.split(',');
diff --git a/Userland/Applications/ThemeEditor/PreviewWidget.cpp b/Userland/Applications/ThemeEditor/PreviewWidget.cpp
index 49ae0f3114..0c23c73ae1 100644
--- a/Userland/Applications/ThemeEditor/PreviewWidget.cpp
+++ b/Userland/Applications/ThemeEditor/PreviewWidget.cpp
@@ -141,7 +141,7 @@ void PreviewWidget::set_preview_palette(const Gfx::Palette& palette)
 
 void PreviewWidget::set_theme_from_file(Core::File& file)
 {
-    auto config_file = Core::ConfigFile::open(file.filename(), file.leak_fd());
+    auto config_file = Core::ConfigFile::open(file.filename(), file.leak_fd()).release_value_but_fixme_should_propagate_errors();
     auto theme = Gfx::load_system_theme(config_file);
     VERIFY(theme.is_valid());
 
diff --git a/Userland/Applications/ThemeEditor/main.cpp b/Userland/Applications/ThemeEditor/main.cpp
index 6c5e9de3ab..77bc9fb4ef 100644
--- a/Userland/Applications/ThemeEditor/main.cpp
+++ b/Userland/Applications/ThemeEditor/main.cpp
@@ -357,7 +357,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
 
         update_window_title();
         auto file = response.value();
-        auto theme = Core::ConfigFile::open(file->filename(), file->leak_fd());
+        auto theme = Core::ConfigFile::open(file->filename(), file->leak_fd()).release_value_but_fixme_should_propagate_errors();
         for (auto role : color_roles) {
             theme->write_entry("Colors", to_string(role), preview_widget.preview_palette().color(role).to_string());
         }
diff --git a/Userland/DevTools/HackStudio/ProjectTemplate.cpp b/Userland/DevTools/HackStudio/ProjectTemplate.cpp
index 34a2523624..2f823c9143 100644
--- a/Userland/DevTools/HackStudio/ProjectTemplate.cpp
+++ b/Userland/DevTools/HackStudio/ProjectTemplate.cpp
@@ -30,7 +30,10 @@ ProjectTemplate::ProjectTemplate(const String& id, const String& name, const Str
 
 RefPtr<ProjectTemplate> ProjectTemplate::load_from_manifest(const String& manifest_path)
 {
-    auto config = Core::ConfigFile::open(manifest_path);
+    auto maybe_config = Core::ConfigFile::open(manifest_path);
+    if (maybe_config.is_error())
+        return {};
+    auto config = maybe_config.release_value();
 
     if (!config->has_group("HackStudioTemplate")
         || !config->has_key("HackStudioTemplate", "Name")
diff --git a/Userland/Libraries/LibCore/ConfigFile.cpp b/Userland/Libraries/LibCore/ConfigFile.cpp
index 4aad3df7e7..3ca378cc02 100644
--- a/Userland/Libraries/LibCore/ConfigFile.cpp
+++ b/Userland/Libraries/LibCore/ConfigFile.cpp
@@ -14,35 +14,35 @@
 
 namespace Core {
 
-NonnullRefPtr<ConfigFile> ConfigFile::open_for_lib(String const& lib_name, AllowWriting allow_altering)
+ErrorOr<NonnullRefPtr<ConfigFile>> ConfigFile::open_for_lib(String const& lib_name, AllowWriting allow_altering)
 {
     String directory = StandardPaths::config_directory();
     auto path = String::formatted("{}/lib/{}.ini", directory, lib_name);
 
-    return adopt_ref(*new ConfigFile(path, allow_altering));
+    return adopt_nonnull_ref_or_enomem(new (nothrow) ConfigFile(path, allow_altering));
 }
 
-NonnullRefPtr<ConfigFile> ConfigFile::open_for_app(String const& app_name, AllowWriting allow_altering)
+ErrorOr<NonnullRefPtr<ConfigFile>> ConfigFile::open_for_app(String const& app_name, AllowWriting allow_altering)
 {
     String directory = StandardPaths::config_directory();
     auto path = String::formatted("{}/{}.ini", directory, app_name);
-    return adopt_ref(*new ConfigFile(path, allow_altering));
+    return adopt_nonnull_ref_or_enomem(new (nothrow) ConfigFile(path, allow_altering));
 }
 
-NonnullRefPtr<ConfigFile> ConfigFile::open_for_system(String const& app_name, AllowWriting allow_altering)
+ErrorOr<NonnullRefPtr<ConfigFile>> ConfigFile::open_for_system(String const& app_name, AllowWriting allow_altering)
 {
     auto path = String::formatted("/etc/{}.ini", app_name);
-    return adopt_ref(*new ConfigFile(path, allow_altering));
+    return adopt_nonnull_ref_or_enomem(new (nothrow) ConfigFile(path, allow_altering));
 }
 
-NonnullRefPtr<ConfigFile> ConfigFile::open(String const& filename, AllowWriting allow_altering)
+ErrorOr<NonnullRefPtr<ConfigFile>> ConfigFile::open(String const& filename, AllowWriting allow_altering)
 {
-    return adopt_ref(*new ConfigFile(filename, allow_altering));
+    return adopt_nonnull_ref_or_enomem(new (nothrow) ConfigFile(filename, allow_altering));
 }
 
-NonnullRefPtr<ConfigFile> ConfigFile::open(String const& filename, int fd)
+ErrorOr<NonnullRefPtr<ConfigFile>> ConfigFile::open(String const& filename, int fd)
 {
-    return adopt_ref(*new ConfigFile(filename, fd));
+    return adopt_nonnull_ref_or_enomem(new (nothrow) ConfigFile(filename, fd));
 }
 
 ConfigFile::ConfigFile(String const& filename, AllowWriting allow_altering)
diff --git a/Userland/Libraries/LibCore/ConfigFile.h b/Userland/Libraries/LibCore/ConfigFile.h
index d2262cbb56..ff3de3bb7b 100644
--- a/Userland/Libraries/LibCore/ConfigFile.h
+++ b/Userland/Libraries/LibCore/ConfigFile.h
@@ -24,11 +24,11 @@ public:
         No,
     };
 
-    static NonnullRefPtr<ConfigFile> open_for_lib(String const& lib_name, AllowWriting = AllowWriting::No);
-    static NonnullRefPtr<ConfigFile> open_for_app(String const& app_name, AllowWriting = AllowWriting::No);
-    static NonnullRefPtr<ConfigFile> open_for_system(String const& app_name, AllowWriting = AllowWriting::No);
-    static NonnullRefPtr<ConfigFile> open(String const& filename, AllowWriting = AllowWriting::No);
-    static NonnullRefPtr<ConfigFile> open(String const& filename, int fd);
+    static ErrorOr<NonnullRefPtr<ConfigFile>> open_for_lib(String const& lib_name, AllowWriting = AllowWriting::No);
+    static ErrorOr<NonnullRefPtr<ConfigFile>> open_for_app(String const& app_name, AllowWriting = AllowWriting::No);
+    static ErrorOr<NonnullRefPtr<ConfigFile>> open_for_system(String const& app_name, AllowWriting = AllowWriting::No);
+    static ErrorOr<NonnullRefPtr<ConfigFile>> open(String const& filename, AllowWriting = AllowWriting::No);
+    static ErrorOr<NonnullRefPtr<ConfigFile>> open(String const& filename, int fd);
     ~ConfigFile();
 
     bool has_group(String const&) const;
diff --git a/Userland/Libraries/LibCore/Version.cpp b/Userland/Libraries/LibCore/Version.cpp
index 9857789871..8a162e9d65 100644
--- a/Userland/Libraries/LibCore/Version.cpp
+++ b/Userland/Libraries/LibCore/Version.cpp
@@ -11,7 +11,7 @@ namespace Core::Version {
 
 String read_long_version_string()
 {
-    auto version_config = Core::ConfigFile::open("/res/version.ini");
+    auto version_config = Core::ConfigFile::open("/res/version.ini").release_value_but_fixme_should_propagate_errors();
     auto major_version = version_config->read_entry("Version", "Major", "0");
     auto minor_version = version_config->read_entry("Version", "Minor", "0");
 
diff --git a/Userland/Libraries/LibDesktop/AppFile.cpp b/Userland/Libraries/LibDesktop/AppFile.cpp
index bbaf23f3c1..d73a468ea1 100644
--- a/Userland/Libraries/LibDesktop/AppFile.cpp
+++ b/Userland/Libraries/LibDesktop/AppFile.cpp
@@ -43,7 +43,7 @@ void AppFile::for_each(Function<void(NonnullRefPtr<AppFile>)> callback, StringVi
 }
 
 AppFile::AppFile(StringView path)
-    : m_config(Core::ConfigFile::open(path))
+    : m_config(Core::ConfigFile::open(path).release_value_but_fixme_should_propagate_errors())
     , m_valid(validate())
 {
 }
diff --git a/Userland/Libraries/LibGUI/FileIconProvider.cpp b/Userland/Libraries/LibGUI/FileIconProvider.cpp
index dbed2680ca..1b14a87a48 100644
--- a/Userland/Libraries/LibGUI/FileIconProvider.cpp
+++ b/Userland/Libraries/LibGUI/FileIconProvider.cpp
@@ -64,7 +64,7 @@ static void initialize_if_needed()
     if (s_initialized)
         return;
 
-    auto config = Core::ConfigFile::open("/etc/FileIconProvider.ini");
+    auto config = Core::ConfigFile::open("/etc/FileIconProvider.ini").release_value_but_fixme_should_propagate_errors();
 
     s_symlink_emblem = Gfx::Bitmap::try_load_from_file("/res/icons/symlink-emblem.png").release_value_but_fixme_should_propagate_errors();
     s_symlink_emblem_small = Gfx::Bitmap::try_load_from_file("/res/icons/symlink-emblem-small.png").release_value_but_fixme_should_propagate_errors();
diff --git a/Userland/Libraries/LibGfx/SystemTheme.cpp b/Userland/Libraries/LibGfx/SystemTheme.cpp
index d6e7d16846..ed52299c08 100644
--- a/Userland/Libraries/LibGfx/SystemTheme.cpp
+++ b/Userland/Libraries/LibGfx/SystemTheme.cpp
@@ -147,7 +147,7 @@ Core::AnonymousBuffer load_system_theme(Core::ConfigFile const& file)
 
 Core::AnonymousBuffer load_system_theme(String const& path)
 {
-    return load_system_theme(Core::ConfigFile::open(path));
+    return load_system_theme(Core::ConfigFile::open(path).release_value_but_fixme_should_propagate_errors());
 }
 
 }
diff --git a/Userland/Libraries/LibLine/Editor.cpp b/Userland/Libraries/LibLine/Editor.cpp
index 02ae0f2496..3863131c10 100644
--- a/Userland/Libraries/LibLine/Editor.cpp
+++ b/Userland/Libraries/LibLine/Editor.cpp
@@ -40,7 +40,7 @@ namespace Line {
 Configuration Configuration::from_config(StringView libname)
 {
     Configuration configuration;
-    auto config_file = Core::ConfigFile::open_for_lib(libname);
+    auto config_file = Core::ConfigFile::open_for_lib(libname).release_value_but_fixme_should_propagate_errors();
 
     // Read behavior options.
     auto refresh = config_file->read_entry("behavior", "refresh", "lazy");
diff --git a/Userland/Libraries/LibTLS/TLSv12.cpp b/Userland/Libraries/LibTLS/TLSv12.cpp
index 0fb57f43ae..bd9a2a4280 100644
--- a/Userland/Libraries/LibTLS/TLSv12.cpp
+++ b/Userland/Libraries/LibTLS/TLSv12.cpp
@@ -345,7 +345,7 @@ Singleton<DefaultRootCACertificates> DefaultRootCACertificates::s_the;
 DefaultRootCACertificates::DefaultRootCACertificates()
 {
     // FIXME: This might not be the best format, find a better way to represent CA certificates.
-    auto config = Core::ConfigFile::open_for_system("ca_certs");
+    auto config = Core::ConfigFile::open_for_system("ca_certs").release_value_but_fixme_should_propagate_errors();
     auto now = Core::DateTime::now();
     auto last_year = Core::DateTime::create(now.year() - 1);
     auto next_year = Core::DateTime::create(now.year() + 1);
diff --git a/Userland/Libraries/LibVT/TerminalWidget.cpp b/Userland/Libraries/LibVT/TerminalWidget.cpp
index c47cdc004d..9c51cf93e8 100644
--- a/Userland/Libraries/LibVT/TerminalWidget.cpp
+++ b/Userland/Libraries/LibVT/TerminalWidget.cpp
@@ -1196,7 +1196,13 @@ void TerminalWidget::set_color_scheme(StringView name)
         "White"
     };
 
-    auto color_config = Core::ConfigFile::open(String::formatted("/res/terminal-colors/{}.ini", name));
+    auto path = String::formatted("/res/terminal-colors/{}.ini", name);
+    auto color_config_or_error = Core::ConfigFile::open(path);
+    if (color_config_or_error.is_error()) {
+        dbgln("Unable to read color scheme file '{}': {}", path, color_config_or_error.error());
+        return;
+    }
+    auto color_config = color_config_or_error.release_value();
 
     m_show_bold_text_as_bright = color_config->read_bool_entry("Options", "ShowBoldTextAsBright", true);
 
diff --git a/Userland/Services/AudioServer/main.cpp b/Userland/Services/AudioServer/main.cpp
index dd8da23147..b659484659 100644
--- a/Userland/Services/AudioServer/main.cpp
+++ b/Userland/Services/AudioServer/main.cpp
@@ -15,7 +15,7 @@ ErrorOr<int> serenity_main(Main::Arguments)
 {
     TRY(Core::System::pledge("stdio recvfd thread accept cpath rpath wpath unix"));
 
-    auto config = Core::ConfigFile::open_for_app("Audio", Core::ConfigFile::AllowWriting::Yes);
+    auto config = TRY(Core::ConfigFile::open_for_app("Audio", Core::ConfigFile::AllowWriting::Yes));
     TRY(Core::System::unveil(config->filename(), "rwc"));
     TRY(Core::System::unveil("/dev/audio", "wc"));
     TRY(Core::System::unveil(nullptr, nullptr));
diff --git a/Userland/Services/ConfigServer/ClientConnection.cpp b/Userland/Services/ConfigServer/ClientConnection.cpp
index 75dab718ae..35ddf332e8 100644
--- a/Userland/Services/ConfigServer/ClientConnection.cpp
+++ b/Userland/Services/ConfigServer/ClientConnection.cpp
@@ -37,14 +37,14 @@ static Core::ConfigFile& ensure_domain_config(String const& domain)
     if (it != s_cache.end())
         return *it->value->config;
 
-    auto config = Core::ConfigFile::open_for_app(domain, Core::ConfigFile::AllowWriting::Yes);
+    auto config = Core::ConfigFile::open_for_app(domain, Core::ConfigFile::AllowWriting::Yes).release_value_but_fixme_should_propagate_errors();
     // FIXME: Use a single FileWatcher with multiple watches inside.
     auto watcher_or_error = Core::FileWatcher::create(InodeWatcherFlags::Nonblock);
     VERIFY(!watcher_or_error.is_error());
     auto result = watcher_or_error.value()->add_watch(config->filename(), Core::FileWatcherEvent::Type::ContentModified);
     VERIFY(!result.is_error());
     watcher_or_error.value()->on_change = [config, domain](auto&) {
-        auto new_config = Core::ConfigFile::open(config->filename(), Core::ConfigFile::AllowWriting::Yes);
+        auto new_config = Core::ConfigFile::open(config->filename(), Core::ConfigFile::AllowWriting::Yes).release_value_but_fixme_should_propagate_errors();
         for (auto& group : config->groups()) {
             for (auto& key : config->keys(group)) {
                 if (!new_config->has_key(group, key)) {
diff --git a/Userland/Services/KeyboardPreferenceLoader/main.cpp b/Userland/Services/KeyboardPreferenceLoader/main.cpp
index 2c035f23a6..cfd231d13c 100644
--- a/Userland/Services/KeyboardPreferenceLoader/main.cpp
+++ b/Userland/Services/KeyboardPreferenceLoader/main.cpp
@@ -17,13 +17,13 @@
 ErrorOr<int> serenity_main(Main::Arguments)
 {
     TRY(Core::System::pledge("stdio proc exec rpath"));
-    auto keyboard_settings_config = Core::ConfigFile::open_for_app("KeyboardSettings");
+    auto keyboard_settings_config = TRY(Core::ConfigFile::open_for_app("KeyboardSettings"));
 
     TRY(Core::System::unveil("/bin/keymap", "x"));
     TRY(Core::System::unveil("/etc/Keyboard.ini", "r"));
     TRY(Core::System::unveil("/dev/keyboard0", "r"));
     TRY(Core::System::unveil(nullptr, nullptr));
-    auto mapper_config(Core::ConfigFile::open("/etc/Keyboard.ini"));
+    auto mapper_config = TRY(Core::ConfigFile::open("/etc/Keyboard.ini"));
     auto keymaps = mapper_config->read_entry("Mapping", "Keymaps", "");
 
     auto keymaps_vector = keymaps.split(',');
diff --git a/Userland/Services/LaunchServer/main.cpp b/Userland/Services/LaunchServer/main.cpp
index befe4af84b..a9c08060d6 100644
--- a/Userland/Services/LaunchServer/main.cpp
+++ b/Userland/Services/LaunchServer/main.cpp
@@ -19,7 +19,7 @@ ErrorOr<int> serenity_main(Main::Arguments)
 
     auto launcher = LaunchServer::Launcher();
     launcher.load_handlers();
-    launcher.load_config(Core::ConfigFile::open_for_app("LaunchServer"));
+    launcher.load_config(TRY(Core::ConfigFile::open_for_app("LaunchServer")));
 
     TRY(Core::System::pledge("stdio accept rpath proc exec"));
 
diff --git a/Userland/Services/LookupServer/LookupServer.cpp b/Userland/Services/LookupServer/LookupServer.cpp
index 676988f8cc..0edaeb6d54 100644
--- a/Userland/Services/LookupServer/LookupServer.cpp
+++ b/Userland/Services/LookupServer/LookupServer.cpp
@@ -37,7 +37,7 @@ LookupServer::LookupServer()
     VERIFY(s_the == nullptr);
     s_the = this;
 
-    auto config = Core::ConfigFile::open_for_system("LookupServer");
+    auto config = Core::ConfigFile::open_for_system("LookupServer").release_value_but_fixme_should_propagate_errors();
     dbgln("Using network config file at {}", config->filename());
     m_nameservers = config->read_entry("DNS", "Nameservers", "1.1.1.1,1.0.0.1").split(',');
 
diff --git a/Userland/Services/SystemServer/main.cpp b/Userland/Services/SystemServer/main.cpp
index 85664277d3..d6b081e57a 100644
--- a/Userland/Services/SystemServer/main.cpp
+++ b/Userland/Services/SystemServer/main.cpp
@@ -489,8 +489,8 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     // This takes care of setting up sockets.
     NonnullRefPtrVector<Service> services;
     auto config = (user)
-        ? Core::ConfigFile::open_for_app("SystemServer")
-        : Core::ConfigFile::open_for_system("SystemServer");
+        ? TRY(Core::ConfigFile::open_for_app("SystemServer"))
+        : TRY(Core::ConfigFile::open_for_system("SystemServer"));
     for (auto name : config->groups()) {
         auto service = Service::construct(*config, name);
         if (service->is_enabled())
diff --git a/Userland/Services/Taskbar/main.cpp b/Userland/Services/Taskbar/main.cpp
index d581256f57..fe7adb4ac9 100644
--- a/Userland/Services/Taskbar/main.cpp
+++ b/Userland/Services/Taskbar/main.cpp
@@ -121,7 +121,7 @@ ErrorOr<NonnullRefPtr<GUI::Menu>> build_system_menu()
     system_menu->add_separator();
 
     // First we construct all the necessary app category submenus.
-    auto category_icons = Core::ConfigFile::open("/res/icons/SystemMenu.ini");
+    auto category_icons = TRY(Core::ConfigFile::open("/res/icons/SystemMenu.ini"));
     HashMap<String, NonnullRefPtr<GUI::Menu>> app_category_menus;
 
     Function<void(String const&)> create_category_menu;
diff --git a/Userland/Services/WindowServer/AppletManager.cpp b/Userland/Services/WindowServer/AppletManager.cpp
index f3cce8d789..607ed20816 100644
--- a/Userland/Services/WindowServer/AppletManager.cpp
+++ b/Userland/Services/WindowServer/AppletManager.cpp
@@ -20,7 +20,7 @@ AppletManager::AppletManager()
 {
     s_the = this;
 
-    auto wm_config = Core::ConfigFile::open("/etc/WindowServer.ini");
+    auto wm_config = Core::ConfigFile::open("/etc/WindowServer.ini").release_value_but_fixme_should_propagate_errors();
     auto order = wm_config->read_entry("Applet", "Order");
     order_vector = order.split(',');
 }
diff --git a/Userland/Services/WindowServer/ClientConnection.cpp b/Userland/Services/WindowServer/ClientConnection.cpp
index 3e5f6fb7d7..0042bf7cec 100644
--- a/Userland/Services/WindowServer/ClientConnection.cpp
+++ b/Userland/Services/WindowServer/ClientConnection.cpp
@@ -786,7 +786,7 @@ Messages::WindowServer::SetSystemThemeResponse ClientConnection::set_system_them
 
 Messages::WindowServer::GetSystemThemeResponse ClientConnection::get_system_theme()
 {
-    auto wm_config = Core::ConfigFile::open("/etc/WindowServer.ini");
+    auto wm_config = Core::ConfigFile::open("/etc/WindowServer.ini").release_value_but_fixme_should_propagate_errors();
     auto name = wm_config->read_entry("Theme", "Name");
     return name;
 }
@@ -798,7 +798,7 @@ void ClientConnection::apply_cursor_theme(String const& name)
 
 Messages::WindowServer::GetCursorThemeResponse ClientConnection::get_cursor_theme()
 {
-    auto config = Core::ConfigFile::open("/etc/WindowServer.ini");
+    auto config = Core::ConfigFile::open("/etc/WindowServer.ini").release_value_but_fixme_should_propagate_errors();
     auto name = config->read_entry("Mouse", "CursorTheme");
     return name;
 }
@@ -822,7 +822,12 @@ Messages::WindowServer::SetSystemFontsResponse ClientConnection::set_system_font
 
     WindowManager::the().invalidate_after_theme_or_font_change();
 
-    auto wm_config = Core::ConfigFile::open("/etc/WindowServer.ini", Core::ConfigFile::AllowWriting::Yes);
+    auto wm_config_or_error = Core::ConfigFile::open("/etc/WindowServer.ini", Core::ConfigFile::AllowWriting::Yes);
+    if (wm_config_or_error.is_error()) {
+        dbgln("Unable to open WindowServer.ini to set system fonts: {}", wm_config_or_error.error());
+        return false;
+    }
+    auto wm_config = wm_config_or_error.release_value();
     wm_config->write_entry("Fonts", "Default", default_font_query);
     wm_config->write_entry("Fonts", "FixedWidth", fixed_width_font_query);
     return true;
diff --git a/Userland/Services/WindowServer/KeymapSwitcher.cpp b/Userland/Services/WindowServer/KeymapSwitcher.cpp
index 3de9a8c373..ac47e2473b 100644
--- a/Userland/Services/WindowServer/KeymapSwitcher.cpp
+++ b/Userland/Services/WindowServer/KeymapSwitcher.cpp
@@ -34,7 +34,7 @@ void KeymapSwitcher::refresh()
 {
     m_keymaps.clear();
 
-    auto mapper_config(Core::ConfigFile::open(m_keyboard_config));
+    auto mapper_config(Core::ConfigFile::open(m_keyboard_config).release_value_but_fixme_should_propagate_errors());
     auto keymaps = mapper_config->read_entry("Mapping", "Keymaps", "");
 
     auto keymaps_vector = keymaps.split(',');
diff --git a/Userland/Services/WindowServer/WindowManager.cpp b/Userland/Services/WindowServer/WindowManager.cpp
index f0f57e4147..feaafc8418 100644
--- a/Userland/Services/WindowServer/WindowManager.cpp
+++ b/Userland/Services/WindowServer/WindowManager.cpp
@@ -74,7 +74,7 @@ WindowManager::~WindowManager()
 
 void WindowManager::reload_config()
 {
-    m_config = Core::ConfigFile::open("/etc/WindowServer.ini", Core::ConfigFile::AllowWriting::Yes);
+    m_config = Core::ConfigFile::open("/etc/WindowServer.ini", Core::ConfigFile::AllowWriting::Yes).release_value_but_fixme_should_propagate_errors();
 
     unsigned workspace_rows = (unsigned)m_config->read_num_entry("Workspace", "Rows", default_window_stack_rows);
     unsigned workspace_columns = (unsigned)m_config->read_num_entry("Workspace", "Columns", default_window_stack_columns);
@@ -2193,9 +2193,15 @@ WindowStack& WindowManager::get_rendering_window_stacks(WindowStack*& transition
     return Compositor::the().get_rendering_window_stacks(transitioning_window_stack);
 }
 
-void WindowManager::apply_cursor_theme(const String& theme_name)
+void WindowManager::apply_cursor_theme(String const& theme_name)
 {
-    auto cursor_theme_config = Core::ConfigFile::open(String::formatted("/res/cursor-themes/{}/{}", theme_name, "Config.ini"));
+    auto theme_path = String::formatted("/res/cursor-themes/{}/{}", theme_name, "Config.ini");
+    auto cursor_theme_config_or_error = Core::ConfigFile::open(theme_path);
+    if (cursor_theme_config_or_error.is_error()) {
+        dbgln("Unable to open cursor theme '{}': {}", theme_path, cursor_theme_config_or_error.error());
+        return;
+    }
+    auto cursor_theme_config = cursor_theme_config_or_error.release_value();
 
     auto* current_cursor = Compositor::the().current_cursor();
     auto reload_cursor = [&](RefPtr<Cursor>& cursor, const String& name) {
diff --git a/Userland/Services/WindowServer/main.cpp b/Userland/Services/WindowServer/main.cpp
index bb26ef29ad..2c56729bd7 100644
--- a/Userland/Services/WindowServer/main.cpp
+++ b/Userland/Services/WindowServer/main.cpp
@@ -36,7 +36,7 @@ ErrorOr<int> serenity_main(Main::Arguments)
     TRY(Core::System::sigaction(SIGCHLD, &act, nullptr));
     TRY(Core::System::pledge("stdio video thread sendfd recvfd accept rpath wpath cpath unix proc exec"));
 
-    auto wm_config = Core::ConfigFile::open("/etc/WindowServer.ini");
+    auto wm_config = TRY(Core::ConfigFile::open("/etc/WindowServer.ini"));
     auto theme_name = wm_config->read_entry("Theme", "Name", "Default");
 
     auto theme = Gfx::load_system_theme(String::formatted("/res/themes/{}.ini", theme_name));
diff --git a/Userland/Utilities/ini.cpp b/Userland/Utilities/ini.cpp
index 191b707e14..e1b7ae904e 100644
--- a/Userland/Utilities/ini.cpp
+++ b/Userland/Utilities/ini.cpp
@@ -31,7 +31,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
         return 1;
     }
 
-    auto config = Core::ConfigFile::open(path, value_to_write ? Core::ConfigFile::AllowWriting::Yes : Core::ConfigFile::AllowWriting::No);
+    auto config = TRY(Core::ConfigFile::open(path, value_to_write ? Core::ConfigFile::AllowWriting::Yes : Core::ConfigFile::AllowWriting::No));
 
     if (value_to_write) {
         config->write_entry(group, key, value_to_write);
diff --git a/Userland/Utilities/keymap.cpp b/Userland/Utilities/keymap.cpp
index 0818798109..8db477cbbf 100644
--- a/Userland/Utilities/keymap.cpp
+++ b/Userland/Utilities/keymap.cpp
@@ -53,7 +53,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
         return 0;
     }
 
-    auto mapper_config(Core::ConfigFile::open("/etc/Keyboard.ini", Core::ConfigFile::AllowWriting::Yes));
+    auto mapper_config = TRY(Core::ConfigFile::open("/etc/Keyboard.ini", Core::ConfigFile::AllowWriting::Yes));
 
     int rc = 0;
 
diff --git a/Userland/Utilities/run-tests.cpp b/Userland/Utilities/run-tests.cpp
index 5941d2f26f..23f33a48b1 100644
--- a/Userland/Utilities/run-tests.cpp
+++ b/Userland/Utilities/run-tests.cpp
@@ -376,7 +376,13 @@ int main(int argc, char** argv)
         return 1;
     }
 
-    auto config = config_file.is_empty() ? Core::ConfigFile::open_for_app("Tests") : Core::ConfigFile::open(config_file);
+    auto config_or_error = config_file.is_empty() ? Core::ConfigFile::open_for_app("Tests") : Core::ConfigFile::open(config_file);
+    if (config_or_error.is_error()) {
+        warnln("Failed to open configuration file ({}): {}", config_file.is_empty() ? "User config for Tests" : config_file.characters(), config_or_error.error());
+        return 1;
+    }
+    auto config = config_or_error.release_value();
+
     if (config->num_groups() == 0)
         warnln("Empty configuration file ({}) loaded!", config_file.is_empty() ? "User config for Tests" : config_file.characters());