Lists: an empty paragraph gets no bullet or number

A list paragraph with no characters before its return draws no label,
and numbering carries on past it: in a story's own list, in named lists
(also across stories) and in cross-reference paragraph numbers.

crates/compose/src/lib.rs

@@ -492,9 +492,10 @@ fn compose_with_db(doc: &Document, story: &Story, frames: &[FrameSpec], opts: &C
         story
             .paras
             .iter()
-            .map(|p| {
+            .zip(&para_ranges)
+            .map(|(p, r)| {
                 let (pp, _) = doc.styles.resolve_para(p);
-                if pp.list_type != designcraft_doc::ListType::Numbers || pp.list_name.is_empty() {
+                if pp.list_type != designcraft_doc::ListType::Numbers || pp.list_name.is_empty() || r.is_empty() {
                     return None;
                 }
                 let c = counters.entry(pp.list_name.clone()).or_insert_with(|| doc.list_start(story.id, &pp.list_name));
@@ -701,6 +702,8 @@ fn compose_with_db(doc: &Document, story: &Story, frames: &[FrameSpec], opts: &C
         // List labels take the default super/subscript settings.
         let label_env = shape::TypeEnv { adv: Default::default(), ..env };
         match pp.list_type {
+            // An empty paragraph has no bullet or number, and the numbering carries on past it.
+            designcraft_doc::ListType::Numbers | designcraft_doc::ListType::Bullets if prange.is_empty() => {}
             designcraft_doc::ListType::Numbers if !pp.list_name.is_empty() => {
                 // A named list: carries on past other paragraphs (and from earlier stories).
                 let n = named_numbers.get(pi).copied().flatten().unwrap_or(1);

crates/compose/src/tests.rs

@@ -2262,3 +2262,21 @@ fn numbering_from_the_largest_start_number_does_not_overflow() {
     let max = format!("{}.", u32::MAX);
     assert_eq!(list_labels(&cs, LABEL_CHARS), [max.clone(), max]);
 }
+
+#[test]
+fn empty_paragraphs_get_no_bullet_or_number() {
+    let bullets = ParaAttrs { list_type: Some(designcraft_doc::ListType::Bullets), ..Default::default() };
+    let (d, sid, _) = doc_with("One\n\nTwo\n", Rect::new(0.0, 0.0, 300.0, 300.0), bullets);
+    let cs = compose_story(&d, sid, &ComposeOptions::default());
+    assert_eq!(list_labels(&cs, LABEL_CHARS), ["\u{2022}", "", "\u{2022}", ""]);
+    // An empty paragraph doesn't use up a number, in a story's own list or a named one.
+    for name in ["", "Steps"] {
+        let attrs = ParaAttrs { list_name: Some(name.into()), ..numbered(designcraft_doc::NumberStyle::Arabic, "^#.^t") };
+        let (mut d, sid, _) = doc_with("One\n\nTwo\n", Rect::new(0.0, 0.0, 300.0, 300.0), attrs);
+        if !name.is_empty() {
+            d.settings.lists.push(designcraft_doc::NumberedList { name: name.into(), continue_across_stories: false });
+        }
+        let cs = compose_story(&d, sid, &ComposeOptions::default());
+        assert_eq!(list_labels(&cs, LABEL_CHARS), ["1.", "", "2.", ""], "list `{name}`");
+    }
+}

crates/doc/src/notes.rs

@@ -235,9 +235,9 @@ impl crate::Document {
         before.sort_by_key(|st| key(st));
         let mut n = 0u32;
         for st in before {
-            for p in &st.paras {
+            for (p, r) in st.paras.iter().zip(st.para_ranges()) {
                 let (pp, _) = self.styles.resolve_para(p);
-                if pp.list_type == crate::ListType::Numbers && pp.list_name == name {
+                if pp.list_type == crate::ListType::Numbers && pp.list_name == name && !r.is_empty() {
                     n = pp.start_at.map_or(n.saturating_add(1), |s| s.max(1));
                 }
             }

crates/doc/src/xref.rs

@@ -347,12 +347,17 @@ impl Document {
         let (sid, pos) = self.find_anchor(id)?;
         let st = self.story(sid)?;
         let pi = st.para_at(pos);
-        let r = st.para_ranges()[pi].clone();
+        let ranges = st.para_ranges();
+        let r = ranges[pi].clone();
         let (pp, _) = self.styles.resolve_para(&st.paras[pi]);
         let para_num = match pp.list_type {
-            crate::ListType::Numbers => {
-                // Count the run of numbered paragraphs before this one.
-                let n = (0..=pi).rev().take_while(|&k| self.styles.resolve_para(&st.paras[k]).0.list_type == crate::ListType::Numbers).count();
+            crate::ListType::Numbers if !r.is_empty() => {
+                // Count the run of numbered paragraphs before this one (empty ones have no number).
+                let n = (0..=pi)
+                    .rev()
+                    .take_while(|&k| self.styles.resolve_para(&st.paras[k]).0.list_type == crate::ListType::Numbers)
+                    .filter(|&k| ranges.get(k).is_some_and(|r| !r.is_empty()))
+                    .count();
                 pp.number_label(u32::try_from(n).unwrap_or(u32::MAX)).trim_end().to_string()
             }
             _ => String::new(),