feat: support macOS modified backspace deletion

src/diff.rs

@@ -1,4 +1,4 @@
-use crate::editor::Input;
+use crate::editor::{BackspaceKind, Input};
 use crate::files::{FilePicker, FilePresentation, FileView};
 use std::{
     collections::BTreeSet,
@@ -506,9 +506,11 @@ impl DiffState {
             Input::Home => self.selected = 0,
             Input::End => self.selected = self.visible.len().saturating_sub(1),
             Input::Enter if !self.loading => self.choose(),
-            Input::Backspace => {
-                if let Some((byte, _)) = self.query.grapheme_indices(true).next_back() {
-                    self.query.truncate(byte);
+            input if BackspaceKind::from_input(&input).is_some() => {
+                if BackspaceKind::from_input(&input)
+                    .expect("guard checked backspace input")
+                    .truncate(&mut self.query)
+                {
                     self.refilter();
                 }
             }
@@ -2113,6 +2115,52 @@ mod tests {
         assert_eq!(editor.diff().unwrap().selected, 1);
     }
 
+    #[test]
+    fn selector_word_and_line_deletion_preserve_source_in_both_stages() {
+        for after in [false, true] {
+            let mut editor = editor();
+            editor
+                .apply(vec![Effect::Replace("source text".into())])
+                .unwrap();
+            let source = editor.context().text;
+            let revision = editor.text_revision();
+            let carets = editor.carets();
+            open(&mut editor);
+            if after {
+                editor.handle(Input::Enter);
+            }
+            let phase = if after { Phase::After } else { Phase::Before };
+            text(&mut editor, "FIX missing");
+            assert_eq!(editor.diff().unwrap().entries().len(), 1);
+            editor.handle(Input::AltBackspace);
+            assert_eq!(editor.diff().unwrap().query, "FIX ");
+            assert_eq!(editor.diff().unwrap().entries().len(), 2);
+            editor.handle(Input::SuperBackspace);
+            assert!(editor.diff().unwrap().query.is_empty());
+            assert_eq!(
+                editor
+                    .diff()
+                    .unwrap()
+                    .entries()
+                    .map(|entry| entry.label.as_str())
+                    .collect::<Vec<_>>(),
+                [
+                    "Working checkout",
+                    "abcdef123",
+                    "fedcba321",
+                    "Load history from origin"
+                ]
+            );
+            for input in [Input::Backspace, Input::AltBackspace, Input::SuperBackspace] {
+                editor.handle(input);
+            }
+            assert_eq!(editor.diff().unwrap().phase, phase);
+            assert_eq!(editor.context().text, source);
+            assert_eq!(editor.text_revision(), revision);
+            assert_eq!(editor.carets(), carets);
+        }
+    }
+
     #[test]
     fn loader_preserves_after_step_query_category_and_selection_then_compares() {
         let mut editor = editor();