M3: preserve IME composition in command search (#1252) (#1638)

Co-authored-by: Codex <[email protected]>

crates/ui-egui/src/palette.rs

@@ -159,15 +159,17 @@ pub fn show(app: &mut PdfCraftApp, ctx: &egui::Context) {
                             .font(theme::regular(15.0))
                             .desired_width(f32::INFINITY),
                     );
-                    // Enter runs the top hit. The field keeps focus (requested every frame), so
-                    // check while it is focused as well as when focus is lost.
+                    // Enter runs the selected hit while the field is focused or relinquishing focus.
                     if (r.has_focus() || r.lost_focus())
                         && ui.input(|i| i.key_pressed(egui::Key::Enter))
                         && let Some((_, h)) = hits.get(selected)
                     {
                         chosen = Some((h.command, h.group));
                     }
-                    r.request_focus();
+                    // Re-requesting existing focus interrupts native IME composition.
+                    if !r.has_focus() {
+                        r.request_focus();
+                    }
                 });
                 ui.separator();
                 for (index, (_, h)) in hits.iter().enumerate() {

crates/ui-egui/tests/commands.rs

@@ -506,3 +506,77 @@ fn command_w_still_closes_the_document_tab_on_macos() {
     h.run_steps(2);
     assert!(h.state().views.is_empty(), "⌘W closes the clean document tab");
 }
+
+fn palette_ime_output_requests_interrupt(h: &Harness<'_, PdfCraftApp>, phase: &str) -> bool {
+    assert!(h.state().palette_open, "palette closed during {phase}");
+    let ime = h.output().platform_output.ime.as_ref().expect("focused palette advertises IME");
+    eprintln!("{phase}: query={:?}; should_interrupt_composition={}", h.state().palette_query, ime.should_interrupt_composition);
+    ime.should_interrupt_composition
+}
+
+fn palette_ime_output_is_uninterrupted(h: &Harness<'_, PdfCraftApp>, phase: &str) {
+    assert!(!palette_ime_output_requests_interrupt(h, phase), "palette interrupted composition during {phase}");
+}
+
+#[test]
+fn palette_ime_idle_frames_and_reopen_do_not_interrupt_composition() {
+    let mut h = harness();
+    for opening in 0..2 {
+        h.state_mut().run_command("view.palette");
+        h.run_steps(3);
+        for frame in 0..3 {
+            h.step();
+            palette_ime_output_is_uninterrupted(&h, &format!("opening {opening}, idle {frame}"));
+        }
+        h.key_press(Key::Escape);
+        h.run_steps(2);
+        assert!(!h.state().palette_open);
+    }
+}
+
+#[test]
+fn palette_ime_chinese_preedit_commit_and_cancel_remain_uninterrupted() {
+    let mut h = harness();
+    let mut interruptions = Vec::new();
+    h.state_mut().run_command("view.palette");
+    h.run_steps(3);
+    for preedit in ["ni", "nih"] {
+        h.event(egui::Event::Ime(egui::ImeEvent::Preedit { text: preedit.into(), active_range_chars: Some(0..preedit.chars().count()) }));
+        h.step();
+        interruptions.push(palette_ime_output_requests_interrupt(&h, preedit));
+        h.step();
+        interruptions.push(palette_ime_output_requests_interrupt(&h, "preedit idle"));
+    }
+    h.event(egui::Event::Ime(egui::ImeEvent::Commit("你".into())));
+    h.step();
+    assert_eq!(h.state().palette_query, "你");
+    interruptions.push(palette_ime_output_requests_interrupt(&h, "Chinese commit"));
+    h.run_steps(2);
+    assert_eq!(h.state().palette_query, "你");
+    interruptions.push(palette_ime_output_requests_interrupt(&h, "committed idle"));
+    h.event(egui::Event::Ime(egui::ImeEvent::Preedit { text: "hao".into(), active_range_chars: Some(0..3) }));
+    h.step();
+    interruptions.push(palette_ime_output_requests_interrupt(&h, "second preedit"));
+    h.event(egui::Event::Ime(egui::ImeEvent::Preedit { text: String::new(), active_range_chars: None }));
+    h.step();
+    assert_eq!(h.state().palette_query, "你");
+    interruptions.push(palette_ime_output_requests_interrupt(&h, "cancel preedit"));
+    assert!(interruptions.iter().all(|interrupt| !interrupt), "composition interrupted: {interruptions:?}");
+}
+
+#[test]
+fn palette_ime_outside_click_closes_without_running_a_command() {
+    let mut h = harness();
+    h.state_mut().set_option("palette", "rotate pages clockwise").unwrap();
+    h.run_steps(3);
+    h.event(egui::Event::PointerButton {
+        pos: egui::pos2(20.0, 850.0),
+        button: egui::PointerButton::Primary,
+        pressed: true,
+        modifiers: Modifiers::NONE,
+    });
+    h.step();
+    assert!(!h.state().palette_open);
+    assert!(h.state().palette_query.is_empty());
+    assert_eq!(h.state().session.get(h.state().views[0].id).unwrap().info.pages[0].rotation, 0);
+}