From caa9fd0f4861d1fa5a61c2f095f1105cdda2def8 Mon Sep 17 00:00:00 2001
From: MarekSpodBiedry <73122968+MarekSpodBiedry@users.noreply.github.com>
Date: Tue, 13 Oct 2026 18:02:34 +0200
Subject: [PATCH] Fix row keys merging distinct text rows in UNIQUE and
 grouping (#1012)

---
 crates/functions/src/dynamic.rs | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/crates/functions/src/dynamic.rs b/crates/functions/src/dynamic.rs
index 2e29b416c..0e5c5aa17 100644
--- a/crates/functions/src/dynamic.rs
+++ b/crates/functions/src/dynamic.rs
@@ -86,8 +86,11 @@ fn key_of(v: &Value) -> String {
 fn row_key(r: &[Value]) -> String {
     let mut s = String::new();
     for v in r {
-        s.push_str(&key_of(v));
-        s.push('\u{1}');
+        let k = key_of(v);
+        // Length prefix keeps the encoding unambiguous even when a text value contains the separator.
+        s.push_str(&k.len().to_string());
+        s.push(':');
+        s.push_str(&k);
     }
     s
 }
@@ -1102,6 +1105,12 @@ mod tests {
         is_err(ev("SORTBY", vec![av(col(&[1.0, 2.0])), av(col(&[1.0, 2.0])), n(0.0)]), CellError::Value);
     }
 
+    #[test]
+    fn unique_keeps_rows_containing_separator_apart() {
+        let m = arr(vec![vec![tv("a"), tv("b\u{1}tc")], vec![tv("a\u{1}tb"), tv("c")]]);
+        assert_eq!(rows_of(&ev("UNIQUE", vec![av(m)])).len(), 2);
+    }
+
     #[test]
     fn unique() {
         let v = arr(vec![vec![tv("a")], vec![tv("B")], vec![tv("A")], vec![tv("c")], vec![tv("b")]]);