config: fix parsing of XF86ScreenSaver key

Closes #1969

1 files changed, 54 insertions, 2 deletions

diff --git a/niri-config/src/binds.rs b/niri-config/src/binds.rs
index 71181fc0..1356d40f 100644
--- a/niri-config/src/binds.rs
+++ b/niri-config/src/binds.rs
@@ -9,7 +9,7 @@ use niri_ipc::{
     ColumnDisplay, LayoutSwitchTarget, PositionChange, SizeChange, WorkspaceReferenceArg,
 };
 use smithay::input::keyboard::keysyms::KEY_NoSymbol;
-use smithay::input::keyboard::xkb::{keysym_from_name, KEYSYM_CASE_INSENSITIVE};
+use smithay::input::keyboard::xkb::{keysym_from_name, KEYSYM_CASE_INSENSITIVE, KEYSYM_NO_FLAGS};
 use smithay::input::keyboard::Keysym;
 
 use crate::utils::{expect_only_children, MergeWith};
@@ -984,7 +984,34 @@ impl FromStr for Key {
         } else if key.eq_ignore_ascii_case("TouchpadScrollRight") {
             Trigger::TouchpadScrollRight
         } else {
-            let keysym = keysym_from_name(key, KEYSYM_CASE_INSENSITIVE);
+            let mut keysym = keysym_from_name(key, KEYSYM_CASE_INSENSITIVE);
+            // The keyboard event handling code can receive either
+            // XF86ScreenSaver or XF86Screensaver, because there is no
+            // case mapping defined between these keysyms. If we just
+            // use the case-insensitive version of keysym_from_name it
+            // is not possible to bind the uppercase version, because the
+            // case-insensitive match prefers the lowercase version when
+            // there is a choice.
+            //
+            // Therefore, when we match this key with the initial
+            // case-insensitive match we try a further case-sensitive match
+            // (so that either key can be bound). If that fails, we change
+            // to the uppercase version because:
+            //
+            // - A comment in xkb_keysym_from_name (in libxkbcommon) tells us that the uppercase
+            //   version is the "best" of the two. [0]
+            // - The xkbcommon crate only has a constant for ScreenSaver. [1]
+            //
+            // [0]: https://github.com/xkbcommon/libxkbcommon/blob/45a118d5325b051343b4b174f60c1434196fa7d4/src/keysym.c#L276
+            // [1]: https://docs.rs/xkbcommon/latest/xkbcommon/xkb/keysyms/index.html#:~:text=KEY%5FXF86ScreenSaver
+            //
+            // See https://github.com/YaLTeR/niri/issues/1969
+            if keysym == Keysym::XF86_Screensaver {
+                keysym = keysym_from_name(key, KEYSYM_NO_FLAGS);
+                if keysym.raw() == KEY_NoSymbol {
+                    keysym = Keysym::XF86_ScreenSaver;
+                }
+            }
             if keysym.raw() == KEY_NoSymbol {
                 return Err(miette!("invalid key: {key}"));
             }
@@ -1000,6 +1027,31 @@ mod tests {
     use super::*;
 
     #[test]
+    fn parse_xf86_screensaver() {
+        assert_eq!(
+            "XF86ScreenSaver".parse::<Key>().unwrap(),
+            Key {
+                trigger: Trigger::Keysym(Keysym::XF86_ScreenSaver),
+                modifiers: Modifiers::empty(),
+            },
+        );
+        assert_eq!(
+            "XF86Screensaver".parse::<Key>().unwrap(),
+            Key {
+                trigger: Trigger::Keysym(Keysym::XF86_Screensaver),
+                modifiers: Modifiers::empty(),
+            }
+        );
+        assert_eq!(
+            "xf86screensaver".parse::<Key>().unwrap(),
+            Key {
+                trigger: Trigger::Keysym(Keysym::XF86_ScreenSaver),
+                modifiers: Modifiers::empty(),
+            }
+        );
+    }
+
+    #[test]
     fn parse_iso_level_shifts() {
         assert_eq!(
             "ISO_Level3_Shift+A".parse::<Key>().unwrap(),