fix: only check for kitty support when it's enabled (#988)

Author: reubeno

src/engine.rs

@@ -240,7 +240,7 @@ impl Reedline {
             buffer_editor: None,
             cursor_shapes: None,
             bracketed_paste: BracketedPasteGuard::default(),
-            kitty_protocol: KittyProtocolGuard::new(),
+            kitty_protocol: KittyProtocolGuard::default(),
             immediately_accept: false,
             #[cfg(feature = "external_printer")]
             external_printer: None,

src/terminal_extensions/kitty.rs

@@ -12,23 +12,24 @@ use crossterm::{event, execute};
 /// * [dte text editor](https://gitlab.com/craigbarnes/dte/-/issues/138)
 ///
 /// Refer to <https://sw.kovidgoyal.net/kitty/keyboard-protocol/> if you're curious.
+#[derive(Default)]
 pub(crate) struct KittyProtocolGuard {
     enabled: bool,
     active: bool,
-    support_kitty_protocol: bool,
+    /// Caches whether the terminal supports the kitty protocol; `None` means we haven't checked yet
+    /// and `Some(bool)` stores a cached answer.
+    support_kitty_protocol: Option<bool>,
 }
 
 impl KittyProtocolGuard {
-    pub fn new() -> Self {
-        Self {
-            support_kitty_protocol: super::kitty_protocol_available(),
-            enabled: false,
-            active: false,
+    pub fn set(&mut self, enable: bool) {
+        // If we are enabling and haven't yet checked for support, do so now. We cache
+        // the result to avoid repeated checks.
+        if enable && self.support_kitty_protocol.is_none() {
+            self.support_kitty_protocol = Some(super::kitty_protocol_available());
         }
-    }
 
-    pub fn set(&mut self, enable: bool) {
-        self.enabled = enable && self.support_kitty_protocol;
+        self.enabled = enable && self.support_kitty_protocol.unwrap_or(false);
     }
     pub fn enter(&mut self) {
         if self.enabled && !self.active {