documents: an empty task ends a list; Shift-Tab takes a tab out; a table on a blank indented line is a table

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

src/documents/document/lists.rs

@@ -50,10 +50,14 @@ pub(super) fn enter(source: &str, at: usize) -> Option<(Range<usize>, String)> {
         "" => " ",
         written => written,
     };
-    let task = matches!(item, mdast::Node::ListItem(item) if item.checked.is_some());
     let body = source[start + after..span(item).end].trim_start();
-    let body = match task {
-        true => body.get(3..).unwrap_or_default(),
+    // A bare box has no `checked`: it is still a task.
+    let boxed = ["[ ]", "[x]", "[X]"]
+        .iter()
+        .any(|task| body.starts_with(task));
+    let task = boxed || matches!(item, mdast::Node::ListItem(item) if item.checked.is_some());
+    let body = match boxed {
+        true => &body[3..],
         false => body,
     };
     let end = source[at..]
@@ -101,6 +105,8 @@ pub(super) fn shift(text: &str, range: Range<usize>, deeper: bool) -> (String, R
         let spaces = line.len() - line.trim_start_matches(' ').len();
         match deeper {
             true => changes.push((at, STEP as isize)),
+            // A leading tab is one step out.
+            false if line.starts_with('\t') => changes.push((at, -1)),
             false if spaces > 0 => changes.push((at, -(spaces.min(STEP) as isize))),
             false => {}
         }

src/documents/document/tables.rs

@@ -214,10 +214,16 @@ impl MarkdownDocument {
         let at = self.editor.read(cx).primary().range().start;
         let end = text[at..].find('\n').map_or(text.len(), |found| at + found);
         let start = text[..at].rfind('\n').map_or(0, |found| found + 1);
-        let before = if text[start..end].trim().is_empty() {
-            ""
-        } else {
-            "\n\n"
+        // A blank line gives way; a written one keeps.
+        let blank = text[start..end].trim().is_empty();
+        let above = text[..start.saturating_sub(1)]
+            .rsplit('\n')
+            .next()
+            .unwrap_or_default();
+        let (from, before) = match (blank, above.trim().is_empty()) {
+            (true, true) => (start, ""),
+            (true, false) => (start, "\n"),
+            (false, _) => (end, "\n\n"),
         };
         let after = if text[end..].starts_with("\n\n") || end == text.len() {
             ""
@@ -225,10 +231,10 @@ impl MarkdownDocument {
             "\n"
         };
         let written = format!("{before}{NEW}{after}");
-        let caret = end + before.len() + 2;
+        let caret = from + before.len() + 2;
         log::info!("markdown document: a table goes in");
         self.editor.update(cx, |editor, cx| {
-            editor.edit([(end..end, written)], cx);
+            editor.edit([(from..end, written)], cx);
             editor.select(std::iter::once(caret..caret), cx);
         });
         Ok(())

src/documents/document/tests/tools.rs

@@ -201,3 +201,43 @@ fn a_newer_match_takes_the_place_of_a_waiting_one(cx: &mut TestAppContext) {
     cx.simulate_input("z");
     assert_eq!(text(&document, cx), "a b z\n");
 }
+
+#[gpui::test]
+fn an_empty_task_ends_the_list(cx: &mut TestAppContext) {
+    let (document, cx) = open("- [x] done", MarkdownMode::Source, cx);
+    document.update(cx, |document, cx| document.set_caret(0, 10, cx));
+    let editor = document.read_with(cx, |document, _| document.editor().clone());
+    let focus = editor.read_with(cx, gpui::Focusable::focus_handle);
+    cx.update(|window, cx| window.focus(&focus, cx));
+    cx.simulate_keystrokes("enter");
+    cx.run_until_parked();
+    cx.simulate_keystrokes("enter");
+    assert_eq!(text(&document, cx), "- [x] done\n");
+}
+
+#[gpui::test]
+fn shift_tab_takes_a_tab_indent_out(cx: &mut TestAppContext) {
+    let (document, cx) = open("- a\n\t- b\n", MarkdownMode::Visual, cx);
+    press(0, Modifiers::none(), cx);
+    cx.simulate_keystrokes("shift-tab");
+    assert_eq!(opened(&document, cx), "- a\n- b");
+}
+
+#[gpui::test]
+fn a_table_on_an_indented_blank_line_is_a_table(cx: &mut TestAppContext) {
+    let (document, cx) = open(
+        "    
+",
+        MarkdownMode::Source,
+        cx,
+    );
+    document.update(cx, |document, cx| {
+        document.set_caret(0, 4, cx);
+        document.insert_table(cx).expect("inserted");
+    });
+    let column = document.update(cx, |document, cx| {
+        document.edit_table(crate::documents::TableEdit::ColumnRight, cx)
+    });
+    assert_eq!(column, Ok(()), "{}", text(&document, cx));
+    assert!(text(&document, cx).starts_with("| "));
+}