feat: track checkout identity for pinned diff editability

src/tui.rs

@@ -4864,7 +4864,7 @@ mod tests {
     fn diff_borders_keep_full_revisions_and_each_panes_own_editability() {
         let mut terminal = Terminal::new(ratatui::backend::TestBackend::new(180, 12)).unwrap();
         let mut panels = WheelPanels::default();
-        for case in ["working", "unlisted", "historical", "binary"] {
+        for case in ["working", "checked_out", "unlisted", "historical", "binary"] {
             let mut file = syntax_diff_file("new.rs", "fn old() {}", "fn new() {}");
             file.status = FileStatus::Renamed;
             file.old_path = Some("old.rs".into());
@@ -4876,14 +4876,14 @@ mod tests {
             let comparison = diff.comparison.as_mut().unwrap();
             comparison.before = "abcdef0123456789 (baseline)".into();
             comparison.after = "fedcba9876543210 (destination)".into();
-            if case != "unlisted" {
+            if matches!(case, "working" | "checked_out" | "binary") {
                 comparison.editable_paths.insert("new.rs".into());
             }
-            if case == "historical" {
+            if matches!(case, "historical" | "checked_out") {
                 diff.after.as_mut().unwrap().target =
                     crate::diff::RevisionTarget::Commit("fedcba9876543210".into());
             }
-            let writable = case == "working";
+            let writable = matches!(case, "working" | "checked_out");
             assert_eq!(diff.after_editable(), writable, "{case}");
             for focus in [Focus::Before, Focus::After] {
                 diff.focus = focus;
@@ -9737,6 +9737,7 @@ end
         }
         git(&["add", "."]);
         git(&["commit", "-qm", "base"]);
+        git(&["commit", "--allow-empty", "-qm", "unmatched checkout"]);
         for index in 0..8 {
             directory.file(
                 &format!("file-{index}.txt"),
@@ -9763,6 +9764,7 @@ end
         ready(&mut session, Phase::Before);
         session.handle(Input::Enter);
         session.handle(Input::Down);
+        session.handle(Input::Down);
         session.handle(Input::Enter);
         ready(&mut session, Phase::View);
         let mut terminal = Terminal::new(ratatui::backend::TestBackend::new(120, 18)).unwrap();