Mark extensible enums in winit-core as #[non_exhaustive]

Event, input source, error, data transfer, native key, IME request,
scroll delta and fullscreen enums can now gain variants without a
breaking change. Backends and examples get wildcard arms where they
matched exhaustively; unknown IME requests are reported as
ImeRequestError::NotSupported and unknown fullscreen modes behave
like Fullscreen::Borderless(None).

winit-android/src/event_loop.rs

@@ -977,6 +977,7 @@ impl CoreWindow for Window {
                 *current_caps = None;
                 self.app.hide_soft_input(true);
             },
+            _ => return Err(ImeRequestError::NotSupported),
         }
 
         Ok(())

winit-appkit/src/cursor.rs

@@ -34,7 +34,7 @@ impl CustomCursor {
     pub(crate) fn new(cursor: CustomCursorSource) -> Result<CustomCursor, RequestError> {
         let cursor = match cursor {
             CustomCursorSource::Image(cursor_image) => cursor_image,
-            CustomCursorSource::Animation { .. } | CustomCursorSource::Url { .. } => {
+            _ => {
                 return Err(NotSupportedError::new("unsupported cursor kind").into());
             },
         };

winit-appkit/src/dnd.rs

@@ -453,6 +453,7 @@ impl PasteboardWriterState {
             SendData::Uris(_) => None,
             SendData::String(string) => Some(NSString::from_str(&string).into()),
             SendData::Bytes(binary) => Some(NSData::from_vec(binary).into()),
+            _ => None,
         }
     }
 }

winit-appkit/src/event_loop.rs

@@ -248,6 +248,7 @@ impl RootActiveEventLoop for ActiveEventLoop {
                                     .chain(Vec::new().into_iter().map(ns_url_from_str)),
                             ),
                             SendData::Bytes(_) => None,
+                            _ => None,
                         }
                     })
                     .into_iter()

winit-appkit/src/window_delegate.rs

@@ -227,6 +227,7 @@ define_class!(
                 // in fullscreen, so we must've reached here by `set_fullscreen`
                 // as it updates the state
                 Some(Fullscreen::Borderless(_)) => (),
+                Some(_) => (),
                 // Otherwise, we must've reached fullscreen by the user clicking
                 // on the green fullscreen button. Update state!
                 None => {
@@ -667,6 +668,7 @@ fn new_window(
                 monitor.ns_screen(mtm).or_else(|| NSScreen::mainScreen(mtm))
             },
             Some(Fullscreen::Borderless(None)) => NSScreen::mainScreen(mtm),
+            Some(_) => NSScreen::mainScreen(mtm),
             None => None,
         };
         let frame = match &screen {
@@ -1683,7 +1685,7 @@ impl WindowDelegate {
                     let monitor = monitor.cast_ref::<MonitorHandle>().unwrap();
                     monitor.ns_screen(mtm)
                 },
-                Fullscreen::Borderless(None) => {
+                _ => {
                     if let Some(monitor) = self.current_monitor_inner() {
                         monitor.ns_screen(mtm)
                     } else {
@@ -1928,6 +1930,7 @@ impl WindowDelegate {
                 self.view().disable_ime();
                 return Ok(());
             },
+            _ => return Err(ImeRequestError::NotSupported),
         };
 
         if let Some((spot, size)) = request_data.cursor_area {

winit-core/src/cursor.rs

@@ -111,6 +111,7 @@ impl_dyn_casting!(CustomCursorProvider);
 ///
 /// See [`CustomCursor`] for more details.
 #[derive(Debug, Clone, Eq, Hash, PartialEq)]
+#[non_exhaustive]
 pub enum CustomCursorSource {
     /// Cursor that is backed by RGBA image.
     ///
@@ -167,6 +168,7 @@ impl CustomCursorSource {
 /// An error produced when using [`CustomCursorSource::from_rgba`] with invalid arguments.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+#[non_exhaustive]
 pub enum BadImage {
     /// Produced when the image dimensions are larger than [`MAX_CURSOR_SIZE`]. This doesn't
     /// guarantee that the cursor will work, but should avoid many platform and device specific
@@ -217,6 +219,7 @@ impl Error for BadImage {}
 /// An error produced when using [`CustomCursorSource::from_animation`] with invalid arguments.
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+#[non_exhaustive]
 pub enum BadAnimation {
     /// Produced when no cursors were supplied.
     Empty,

winit-core/src/data_transfer.rs

@@ -127,6 +127,7 @@ impl DataTransferId {
 
 /// The set of types supported cross-platform.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+#[non_exhaustive]
 pub enum TypeHint {
     /// Plain UTF-8 text (see [`TypedData::try_as_string`]).
     ///
@@ -381,6 +382,7 @@ impl_dyn_casting!(DataTransfer);
 /// different encoding on different platforms. To allow this to be represented, we allow
 /// supplying strings and URIs separately from binary blobs.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[non_exhaustive]
 pub enum SendData {
     /// List of URIs.
     ///

winit-core/src/event.rs

@@ -20,6 +20,7 @@ use crate::window::{ActivationToken, Theme};
 
 /// Describes the reason the event loop is resuming.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+#[non_exhaustive]
 pub enum StartCause {
     /// Sent if the time specified by [`ControlFlow::WaitUntil`] has been reached. Contains the
     /// moment the timeout was requested and the requested resume time. The actual resume time is
@@ -44,6 +45,7 @@ pub enum StartCause {
 
 /// Describes an event from a [`Window`].
 #[derive(Debug, Clone, PartialEq)]
+#[non_exhaustive]
 pub enum WindowEvent {
     /// The activation token was delivered back and now could be used.
     ActivationTokenDone { serial: AsyncRequestSerial, token: ActivationToken },
@@ -531,6 +533,7 @@ pub enum WindowEvent {
 /// **Wayland/X11:** [`Unknown`](Self::Unknown) device types are converted to known variants by the
 /// system.
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+#[non_exhaustive]
 pub enum PointerKind {
     Mouse,
     /// See [`PointerSource::Touch`] for more details.
@@ -548,6 +551,7 @@ pub enum PointerKind {
 /// **Wayland/X11:** [`Unknown`](Self::Unknown) device types are converted to known variants by the
 /// system.
 #[derive(Clone, Debug, PartialEq)]
+#[non_exhaustive]
 pub enum PointerSource {
     Mouse,
     /// Represents a touch event.
@@ -616,6 +620,7 @@ impl From<PointerSource> for PointerKind {
 /// **Wayland/X11:** [`Unknown`](Self::Unknown) device types are converted to known variants by the
 /// system.
 #[derive(Clone, Debug, PartialEq)]
+#[non_exhaustive]
 pub enum ButtonSource {
     /// ## Platform-specific
     ///
@@ -730,6 +735,7 @@ impl FingerId {
 ///
 /// [window events]: WindowEvent
 #[derive(Clone, Copy, Debug, PartialEq)]
+#[non_exhaustive]
 pub enum DeviceEvent {
     /// Change in physical position of a pointing device.
     ///
@@ -1052,6 +1058,7 @@ impl From<ModifiersState> for Modifiers {
 /// ```
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[non_exhaustive]
 pub enum Ime {
     /// Notifies when the IME was enabled.
     ///
@@ -1576,6 +1583,7 @@ impl From<TabletToolButton> for Option<MouseButton> {
 /// Describes a difference in the mouse scroll wheel state.
 #[derive(Debug, Clone, Copy, PartialEq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[non_exhaustive]
 pub enum MouseScrollDelta {
     /// Amount in lines or rows to scroll in the horizontal
     /// and vertical directions.

winit-core/src/event_loop/mod.rs

@@ -282,6 +282,7 @@ impl From<Icon> for DragIcon {
 /// are expected to provide some kind of order of preference.
 #[repr(u8)]
 #[derive(Debug, Clone, Copy, PartialEq)]
+#[non_exhaustive]
 pub enum DndAction {
     /// Move the dragged item from the source to the destination.
     ///

winit-core/src/icon.rs

@@ -26,6 +26,7 @@ impl_dyn_casting!(IconProvider);
 
 #[derive(Debug)]
 /// An error produced when using [`RgbaIcon::new`] with invalid arguments.
+#[non_exhaustive]
 pub enum BadIcon {
     /// Produced when the length of the `rgba` argument isn't divisible by 4, thus `rgba` can't be
     /// safely interpreted as 32bpp RGBA pixels.

winit-core/src/keyboard.rs

@@ -19,6 +19,7 @@ pub use smol_str::SmolStr;
 /// - On non-Web platforms, support assigning keybinds to virtually any key through a UI.
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[non_exhaustive]
 pub enum NativeKeyCode {
     Unidentified,
     /// An Android "scancode".
@@ -78,6 +79,7 @@ impl std::fmt::Debug for NativeKeyCode {
 /// define keybinds which work in the presence of identifiers we haven't mapped for you yet.
 #[derive(Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[non_exhaustive]
 pub enum NativeKey {
     Unidentified,
     /// An Android "keycode", which is similar to a "virtual-key code" on Windows.

winit-core/src/monitor.rs

@@ -183,6 +183,7 @@ impl fmt::Display for VideoMode {
 
 /// Fullscreen modes.
 #[derive(Clone, Debug, PartialEq, Eq)]
+#[non_exhaustive]
 pub enum Fullscreen {
     Exclusive(MonitorHandle, VideoMode),
 

winit-core/src/window.rs

@@ -1756,6 +1756,7 @@ bitflags! {
 }
 
 #[derive(Debug, PartialEq, Eq, Clone, Hash)]
+#[non_exhaustive]
 pub enum ImeSurroundingTextError {
     /// Text exceeds 4000 bytes
     TextTooLong,
@@ -1868,6 +1869,7 @@ impl ImeSurroundingText {
 
 /// Request to send to IME.
 #[derive(Debug, PartialEq, Clone)]
+#[non_exhaustive]
 pub enum ImeRequest {
     /// Enable the IME with the [`ImeCapabilities`] and [`ImeRequestData`] as initial state. When
     /// the [`ImeRequestData`] is **not** matching capabilities fully, the default values will be

winit-orbital/src/window.rs

@@ -342,6 +342,7 @@ impl CoreWindow for Window {
             None => {
                 let _ = self.set_flag(ORBITAL_FLAG_FULLSCREEN, false);
             },
+            Some(_) => (),
         }
     }
 

winit-uikit/src/window.rs

@@ -323,9 +323,7 @@ impl Inner {
             Some(Fullscreen::Borderless(Some(monitor))) => {
                 monitor.cast_ref::<MonitorHandle>().unwrap().ui_screen(mtm).clone()
             },
-            Some(Fullscreen::Borderless(None)) => {
-                self.current_monitor_inner().ui_screen(mtm).clone()
-            },
+            Some(_) => self.current_monitor_inner().ui_screen(mtm).clone(),
             None => {
                 warn!("`Window::set_fullscreen(None)` ignored on iOS");
                 return;
@@ -405,6 +403,7 @@ impl Inner {
                 *current_caps = None;
                 self.view.resignFirstResponder();
             },
+            _ => return Err(ImeRequestError::NotSupported),
         }
 
         Ok(())
@@ -522,7 +521,7 @@ impl Window {
                 let monitor = monitor.cast_ref::<MonitorHandle>().unwrap();
                 monitor.ui_screen(mtm)
             },
-            Some(Fullscreen::Borderless(None)) | None => &main_screen,
+            _ => &main_screen,
         };
 
         let screen_bounds = screen.bounds();

winit-wayland/src/dnd.rs

@@ -85,6 +85,7 @@ impl DataSourceHandler for WinitState {
                 },
             },
             SendData::Bytes(binary) => Cursor::new(binary),
+            _ => return,
         };
 
         let _ = self.loop_handle.insert_source(fd, move |_, file, _| {

winit-wayland/src/event_loop/mod.rs

@@ -694,7 +694,7 @@ impl RootActiveEventLoop for ActiveEventLoop {
     ) -> Result<CoreCustomCursor, RequestError> {
         let cursor_image = match cursor {
             CustomCursorSource::Image(cursor_image) => cursor_image,
-            CustomCursorSource::Animation { .. } | CustomCursorSource::Url { .. } => {
+            _ => {
                 return Err(NotSupportedError::new("unsupported cursor kind").into());
             },
         };

winit-wayland/src/window/mod.rs

@@ -453,9 +453,6 @@ impl CoreWindow for Window {
 
     fn set_fullscreen(&self, fullscreen: Option<Fullscreen>) {
         match fullscreen {
-            Some(Fullscreen::Exclusive(..)) => {
-                warn!("`Fullscreen::Exclusive` is ignored on Wayland");
-            },
             Some(Fullscreen::Borderless(monitor)) => {
                 let output = monitor.as_ref().and_then(|monitor| {
                     monitor.cast_ref::<output::MonitorHandle>().map(|handle| &handle.proxy)
@@ -463,6 +460,9 @@ impl CoreWindow for Window {
 
                 self.window.set_fullscreen(output)
             },
+            Some(_) => {
+                warn!("this fullscreen mode is ignored on Wayland");
+            },
             None => self.window.unset_fullscreen(),
         }
     }

winit-wayland/src/window/state.rs

@@ -1269,6 +1269,7 @@ impl WindowState {
                 self.text_input_state = None;
                 true
             },
+            _ => return Err(ImeRequestError::NotSupported),
         };
 
         // Only one input method may be active per (seat, surface),

winit-web/src/cursor.rs

@@ -54,6 +54,7 @@ impl CustomCursor {
                     true,
                 )
             },
+            _ => unimplemented!("unknown `CustomCursorSource` variant"),
         }
     }
 

winit-web/src/web_sys/event.rs

@@ -153,7 +153,7 @@ pub fn pointer_source(event: &PointerEvent, kind: PointerKind) -> PointerSource
 
             PointerSource::TabletTool { kind: tool, data }
         },
-        PointerKind::Unknown => PointerSource::Unknown,
+        _ => PointerSource::Unknown,
     }
 }
 

winit-web/src/web_sys/fullscreen.rs

@@ -88,6 +88,7 @@ pub(crate) fn request_fullscreen(
                 canvas.webkit_request_fullscreen();
             }
         },
+        _ => error!("This full screen mode is not supported"),
     }
 }
 

winit-web/src/web_sys/pointer.rs

@@ -90,7 +90,7 @@ impl PointerHandler {
                     PointerSource::TabletTool { kind, data } => {
                         ButtonSource::TabletTool { kind, button: event::tool_button(button), data }
                     },
-                    PointerSource::Unknown => ButtonSource::Unknown(button),
+                    _ => ButtonSource::Unknown(button),
                 };
 
                 handler(
@@ -152,7 +152,7 @@ impl PointerHandler {
 
                         ButtonSource::TabletTool { kind, button: event::tool_button(button), data }
                     },
-                    PointerSource::Unknown => ButtonSource::Unknown(button),
+                    _ => ButtonSource::Unknown(button),
                 };
 
                 handler(
@@ -229,7 +229,7 @@ impl PointerHandler {
                             button: event::tool_button(button),
                             data,
                         },
-                        PointerSource::Unknown => ButtonSource::Unknown(button),
+                        _ => ButtonSource::Unknown(button),
                     };
 
                     button_handler(

winit-win32/src/dnd.rs

@@ -247,6 +247,7 @@ impl TypedData for WinTypedData {
             },
             // Windows URI drag-and-drop can't be neatly expressed as a binary blob.
             SendData::Uris(_) => None,
+            _ => None,
         }
     }
 
@@ -924,6 +925,7 @@ unsafe fn send_data_to_stgmedium(data: SendData, hint: TypeHint) -> Option<STGME
             hglobal
         },
         SendData::Bytes(b) => alloc_hglobal_from(&b)?,
+        _ => return None,
     };
 
     let mut medium = unsafe { std::mem::zeroed::<STGMEDIUM>() };

winit-win32/src/event_loop.rs

@@ -431,7 +431,7 @@ impl RootActiveEventLoop for ActiveEventLoop {
     ) -> Result<CustomCursor, RequestError> {
         let cursor = match source {
             CustomCursorSource::Image(cursor) => cursor,
-            CustomCursorSource::Animation { .. } | CustomCursorSource::Url { .. } => {
+            _ => {
                 return Err(NotSupportedError::new("unsupported cursor kind").into());
             },
         };
@@ -1397,6 +1397,7 @@ unsafe fn public_window_callback_inner(
                                 window_pos.cy = old_monitor_rect.bottom - old_monitor_rect.top;
                             }
                         },
+                        _ => (),
                     }
                 }
             }

winit-win32/src/window.rs

@@ -967,7 +967,7 @@ impl CoreWindow for Window {
                         | Fullscreen::Borderless(Some(monitor)) => {
                             Some(Cow::Borrowed(monitor.cast_ref::<MonitorHandle>().unwrap()))
                         },
-                        Fullscreen::Borderless(None) => None,
+                        _ => None,
                     };
 
                     let monitor = monitor
@@ -1068,7 +1068,8 @@ impl CoreWindow for Window {
         match &request {
             ImeRequest::Enable(..) if cap.is_some() => return Err(ImeRequestError::AlreadyEnabled),
             ImeRequest::Update(_) if cap.is_none() => return Err(ImeRequestError::NotEnabled),
-            _ => (),
+            ImeRequest::Enable(..) | ImeRequest::Update(_) | ImeRequest::Disable => (),
+            _ => return Err(ImeRequestError::NotSupported),
         }
 
         let window = self.window;
@@ -1096,6 +1097,7 @@ impl CoreWindow for Window {
                     ImeContext::set_ime_allowed(window.hwnd(), false);
                     return;
                 },
+                _ => return,
             };
 
             if let Some((spot, size)) = request_data.cursor_area {

winit-x11/src/util/cursor.rs

@@ -199,7 +199,7 @@ impl CustomCursor {
     ) -> Result<CustomCursor, RequestError> {
         let mut cursor = match cursor {
             CustomCursorSource::Image(cursor_image) => cursor_image,
-            CustomCursorSource::Animation { .. } | CustomCursorSource::Url { .. } => {
+            _ => {
                 return Err(NotSupportedError::new("unsupported cursor kind").into());
             },
         };

winit-x11/src/window.rs

@@ -1105,9 +1105,7 @@ impl UnownedWindow {
                             let monitor = monitor.cast_ref::<X11MonitorHandle>().unwrap();
                             (Cow::Borrowed(monitor), None)
                         },
-                        Fullscreen::Borderless(None) => {
-                            (Cow::Owned(self.shared_state_lock().last_monitor.clone()), None)
-                        },
+                        _ => (Cow::Owned(self.shared_state_lock().last_monitor.clone()), None),
                     };
 
                 // Don't set fullscreen on an invalid dummy monitor handle
@@ -2144,6 +2142,7 @@ impl UnownedWindow {
                 self.set_ime_allowed(false);
                 return Ok(());
             },
+            _ => return Err(ImeRequestError::NotSupported),
         };
 
         if let Some((position, size)) = state.cursor_area {

winit/examples/application.rs

@@ -457,6 +457,7 @@ impl ApplicationHandler for Application {
                 MouseScrollDelta::PixelDelta(px) => {
                     info!("Mouse wheel Pixel Delta: ({},{})", px.x, px.y);
                 },
+                _ => (),
             },
             WindowEvent::KeyboardInput { event, is_synthetic: false, .. } => {
                 let mods = window.modifiers;

winit/examples/ime.rs

@@ -248,6 +248,7 @@ impl App {
                 }
             },
             Ime::Disabled => info!("IME disabled for Window={:?}", surface.window().id()),
+            _ => (),
         }
     }