Duplicate: number the copy from the shape count, not the count of distinct names

crates/engine/src/cmd/edit.rs

@@ -330,7 +330,7 @@ fn paste(s: &mut Session, p: &Value) -> Result<Value> {
                     && !n.is_empty()
                     && n.bytes().all(|b| b.is_ascii_digit())
                 {
-                    sh.name = super::insert::first_free_name(base, &taken);
+                    sh.name = super::insert::first_free_name(base, &taken, taken.len());
                 }
                 taken.insert(sh.name.clone());
                 if let Some(x) = sh.xfrm.as_mut() {
@@ -512,11 +512,11 @@ fn paste_text(s: &mut Session, p: &Value) -> Result<Value> {
 /// PowerPoint does, and keeps a name the user chose. PowerPoint tells the two apart by comparing
 /// the number with the shape's id; ids here are numbered across the deck, so any "{kind} {n}"
 /// counts as automatic.
-fn rename_automatic(sh: &mut Shape, taken: &mut std::collections::HashSet<String>) {
+fn rename_automatic(sh: &mut Shape, taken: &mut std::collections::HashSet<String>, count: usize) {
     let base = if sh.is_group() { "Group".to_string() } else { super::insert::auto_name_base(sh) };
     let n = sh.name.strip_prefix(&base).and_then(|r| r.strip_prefix(' '));
     if n.is_some_and(|n| !n.is_empty() && n.bytes().all(|b| b.is_ascii_digit())) {
-        sh.name = super::insert::first_free_name(&base, taken);
+        sh.name = super::insert::first_free_name(&base, taken, count);
         taken.insert(sh.name.clone());
     }
 }
@@ -547,10 +547,15 @@ fn duplicate(s: &mut Session, p: &Value) -> Result<Value> {
         reid("edit.duplicate", doc, &mut copies)?;
         // Every name on the slide, group members included, so a copy never repeats one.
         let mut taken = std::collections::HashSet::new();
+        let mut count = 0;
         deckcraft_model::walk(&list, &mut |sh, _| {
             taken.insert(sh.name.clone());
+            count += 1;
+        });
+        walk_mut(&mut copies, &mut |c| {
+            rename_automatic(c, &mut taken, count);
+            count += 1;
         });
-        walk_mut(&mut copies, &mut |c| rename_automatic(c, &mut taken));
         for (c, b) in copies.iter_mut().zip(boxes) {
             let mut x = b;
             x.x += dx;

crates/engine/src/cmd/insert.rs

@@ -172,9 +172,10 @@ pub(crate) fn auto_name_base(shape: &Shape) -> String {
 }
 
 /// "{base} n" with the first `n` from the shape count + 1 that no shape on the slide already uses,
-/// so a gap left by a deleted shape never makes a second shape with the same name.
-pub(crate) fn first_free_name(base: &str, taken: &std::collections::HashSet<String>) -> String {
-    (taken.len() + 1..).map(|n| format!("{base} {n}")).find(|c| !taken.contains(c)).unwrap_or_default()
+/// so a gap left by a deleted shape never makes a second shape with the same name. `count` is the
+/// number of shapes, which exceeds the number of names when two shapes share one.
+pub(crate) fn first_free_name(base: &str, taken: &std::collections::HashSet<String>, count: usize) -> String {
+    (count + 1..).map(|n| format!("{base} {n}")).find(|c| !taken.contains(c)).unwrap_or_default()
 }
 
 pub(crate) fn add_shape(s: &mut Session, cmd: &str, mut shape: Shape, select: bool) -> Result<ShapeId> {
@@ -183,7 +184,7 @@ pub(crate) fn add_shape(s: &mut Session, cmd: &str, mut shape: Shape, select: bo
         if shape.name.is_empty() {
             let base = auto_name_base(&shape);
             let taken = super::current_names(doc, sel);
-            shape.name = first_free_name(&base, &taken);
+            shape.name = first_free_name(&base, &taken, taken.len());
         }
         let id = shape.id;
         let list = crate::shapes_mut(doc, sel).ok_or_else(|| bad("insert", "no slide"))?;