documents: undo in an untouched block steps the document; visual after preview opens an empty end

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/documents/document/edit.rs

@@ -1,6 +1,6 @@
 use std::ops::Range;
 
-use gpui::{AppContext as _, Context, Focusable as _, Window};
+use gpui::{App, AppContext as _, Context, Focusable as _, Window};
 
 use super::{DocumentEvent, MarkdownDocument, Open};
 use crate::{
@@ -31,6 +31,24 @@ impl MarkdownDocument {
         }
     }
 
+    /// The open block still holds what it opened with.
+    pub(super) fn untouched(&self, cx: &App) -> bool {
+        self.open.as_ref().is_some_and(|open| {
+            open.input.read(cx).text() == &self.editor.read(cx).text()[open.range.clone()]
+        })
+    }
+
+    /// Undo or redo in the document's one history.
+    pub(super) fn history(&mut self, redo: bool, window: &mut Window, cx: &mut Context<Self>) {
+        self.commit(cx);
+        self.editor.update(cx, |editor, cx| match redo {
+            true => editor.redo(cx),
+            false => editor.undo(cx),
+        });
+        window.focus(&self.focus, cx);
+        self.focused(window, cx);
+    }
+
     /// Opens block `ix` as shown, or one past the end.
     pub(super) fn open(
         &mut self,

src/documents/document/mod.rs

@@ -170,6 +170,8 @@ impl MarkdownDocument {
         }
         let focus = self.focus_handle(cx);
         window.focus(&focus, cx);
+        // Preview to visual keeps one handle: no focus event.
+        self.focused(window, cx);
         cx.notify();
     }
 

src/documents/document/tests/mod.rs

@@ -425,3 +425,50 @@ fn focus_opens_no_block_in_a_written_document(cx: &mut TestAppContext) {
     cx.simulate_input("x");
     assert_eq!(text(&document, cx), TEXT);
 }
+
+fn mode(document: &Entity<MarkdownDocument>, mode: MarkdownMode, cx: &mut VisualTestContext) {
+    document.update_in(cx, |document, window, cx| {
+        document.set_mode(mode, window, cx)
+    });
+    cx.run_until_parked();
+}
+
+#[gpui::test]
+fn preview_and_back_still_take_typing_in_an_empty_document(cx: &mut TestAppContext) {
+    let (document, cx) = open("", MarkdownMode::Visual, cx);
+    focus(&document, cx);
+    cx.simulate_keystrokes("escape");
+    mode(&document, MarkdownMode::Preview, cx);
+    mode(&document, MarkdownMode::Visual, cx);
+    cx.simulate_input("Hi");
+    assert_eq!(text(&document, cx), "Hi");
+}
+
+#[gpui::test]
+fn undo_in_an_untouched_block_steps_the_document(cx: &mut TestAppContext) {
+    let (document, cx) = open("Seed", MarkdownMode::Source, cx);
+    document.update(cx, |document, cx| document.set_text("", cx));
+    mode(&document, MarkdownMode::Visual, cx);
+    cx.simulate_keystrokes("secondary-z");
+    cx.run_until_parked();
+    assert_eq!(text(&document, cx), "Seed", "the source edit is undone");
+    cx.simulate_keystrokes("secondary-shift-z");
+    cx.run_until_parked();
+    assert_eq!(text(&document, cx), "", "and redone");
+}
+
+#[gpui::test]
+fn undo_in_a_typed_block_stays_in_the_block(cx: &mut TestAppContext) {
+    let (document, cx) = open("Seed", MarkdownMode::Source, cx);
+    document.update(cx, |document, cx| document.set_text(TEXT, cx));
+    mode(&document, MarkdownMode::Visual, cx);
+    press(1, Modifiers::none(), cx);
+    cx.simulate_input(" x");
+    cx.simulate_keystrokes("secondary-z");
+    cx.run_until_parked();
+    assert_eq!(
+        text(&document, cx),
+        TEXT,
+        "the typing went, not the edit before"
+    );
+}

src/documents/document/visual.rs

@@ -7,7 +7,7 @@ use gpui::{
 use super::MarkdownDocument;
 use crate::{
     documents::{MarkdownMode, render::draw_nodes},
-    forms::{Down, Up},
+    forms::{self, Down, Up},
     primitives::FocusRing as _,
     theme::{ActiveTheme, Radius, TextSize},
 };
@@ -158,13 +158,24 @@ impl Render for MarkdownDocument {
             MarkdownMode::Visual => root
                 .key_context(CONTEXT)
                 .track_focus(&self.focus)
-                .on_action(cx.listener(|document, _: &Undo, _, cx| {
-                    document.commit(cx);
-                    document.editor.update(cx, |editor, cx| editor.undo(cx));
+                .on_action(cx.listener(|document, _: &Undo, window, cx| {
+                    document.history(false, window, cx);
                 }))
-                .on_action(cx.listener(|document, _: &Redo, _, cx| {
-                    document.commit(cx);
-                    document.editor.update(cx, |editor, cx| editor.redo(cx));
+                .on_action(cx.listener(|document, _: &Redo, window, cx| {
+                    document.history(true, window, cx);
+                }))
+                // An untouched block leaves undo to the document.
+                .capture_action(cx.listener(|document, _: &forms::Undo, window, cx| {
+                    if document.untouched(cx) {
+                        cx.stop_propagation();
+                        document.history(false, window, cx);
+                    }
+                }))
+                .capture_action(cx.listener(|document, _: &forms::Redo, window, cx| {
+                    if document.untouched(cx) {
+                        cx.stop_propagation();
+                        document.history(true, window, cx);
+                    }
                 }))
                 .capture_action(cx.listener(|document, _: &Up, window, cx| {
                     if document.step(false, window, cx) {