From 34125d7e43f572e13b57ef19e0e6d168730ea08c Mon Sep 17 00:00:00 2001
From: MarekSpodBiedry <73122968+MarekSpodBiedry@users.noreply.github.com>
Date: Mon, 12 Oct 2026 08:27:26 +0200
Subject: [PATCH] Quote sheet names when printing sheet-qualified defined names
 (#567)

---
 crates/formula/src/adjust.rs  |  7 +++----
 crates/formula/src/printer.rs | 10 +++++++++-
 crates/formula/src/tests.rs   | 11 +++++++++++
 3 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/crates/formula/src/adjust.rs b/crates/formula/src/adjust.rs
index 6f01e05..d4881aa 100644
--- a/crates/formula/src/adjust.rs
+++ b/crates/formula/src/adjust.rs
@@ -264,11 +264,10 @@ pub fn rename_sheet(e: Expr, old: &str, new: &str) -> Expr {
             }
             Expr::Ref(r)
         }
-        // Sheet-qualified defined name `Old!MyName` is stored as one string.
+        // Sheet-qualified defined name `Old!MyName` is stored as one string, with the bare sheet name as the parser
+        // stores it (the printer adds the quotes).
         Expr::Name(n) => match n.split_at_checked(old.len()) {
-            Some((head, rest)) if head.eq_ignore_ascii_case(old) && rest.starts_with('!') => {
-                Expr::Name(format!("{}{rest}", crate::printer::quote_sheet(new)))
-            }
+            Some((head, rest)) if head.eq_ignore_ascii_case(old) && rest.starts_with('!') => Expr::Name(format!("{new}{rest}")),
             _ => Expr::Name(n),
         },
         other => other,
diff --git a/crates/formula/src/printer.rs b/crates/formula/src/printer.rs
index a63599b..a1ff7a7 100644
--- a/crates/formula/src/printer.rs
+++ b/crates/formula/src/printer.rs
@@ -178,7 +178,15 @@ fn write_expr(s: &mut String, e: &Expr, r1c1: Option<CellRef>) {
             Some(at) => s.push_str(&reference_r1c1(r, at)),
             None => s.push_str(&reference_a1(r)),
         },
-        Expr::Name(n) => s.push_str(n),
+        Expr::Name(n) => match n.rsplit_once('!') {
+            // A sheet-qualified name is stored with the bare sheet name (`My Sheet!Total`): quote it so it parses back.
+            Some((sheet, name)) => {
+                s.push_str(&quote_sheet(sheet));
+                s.push('!');
+                s.push_str(name);
+            }
+            _ => s.push_str(n),
+        },
         Expr::Struct(st) => s.push_str(&struct_ref(st)),
         Expr::Unary(op, x) => match op {
             UnOp::Neg => {
diff --git a/crates/formula/src/tests.rs b/crates/formula/src/tests.rs
index d3dd4c2..66e1f01 100644
--- a/crates/formula/src/tests.rs
+++ b/crates/formula/src/tests.rs
@@ -5,6 +5,13 @@ fn rt(src: &str) -> String {
     print(&parse(src).unwrap_or_else(|e| panic!("{src}: {e}")))
 }
 
+#[test]
+fn quoted_sheet_qualified_name_keeps_quotes() {
+    assert_eq!(rt("'My Sheet'!Total"), "'My Sheet'!Total");
+    assert_eq!(rt("'Data'!Total"), "Data!Total");
+    assert_eq!(rt("'It''s'!Total+1"), "'It''s'!Total+1");
+}
+
 #[test]
 fn roundtrips() {
     for f in [
@@ -183,6 +190,10 @@ fn rename_sheet_updates_qualified_names() {
     assert_eq!(print(&rename_sheet(e, "data", "Numbers")), "Numbers!MyName+MyName+Other!MyName");
     let e = parse("Data!MyName").unwrap();
     assert_eq!(print(&rename_sheet(e, "Data", "New Name")), "'New Name'!MyName");
+    // Stored bare, like a parsed name, so the evaluator finds the sheet and a second rename still matches.
+    let e = rename_sheet(parse("Data!MyName").unwrap(), "Data", "It's");
+    assert_eq!(e, Expr::Name("It's!MyName".into()));
+    assert_eq!(print(&rename_sheet(e, "It's", "Totals")), "Totals!MyName");
 }
 
 #[test]