Merge pull request #6096 from Silvertree2010/fix/h7987-psd-export-writes-a-lone-utf-16

Cut PSD Unicode layer names on a character boundary

crates/render/src/encode/psd.rs

@@ -222,7 +222,16 @@ impl Record {
         extra.push(ascii.len() as u8);
         extra.extend(ascii);
         extra.resize(extra.len().next_multiple_of(4), 0);
-        let units: Vec<u16> = self.name.encode_utf16().take(255).collect();
+        // Cut before the character that would pass 255 units, never inside a surrogate pair.
+        let mut units: Vec<u16> = vec![];
+        for c in self.name.chars() {
+            let mut buf = [0; 2];
+            let encoded = c.encode_utf16(&mut buf);
+            if units.len() + encoded.len() > 255 {
+                break;
+            }
+            units.extend_from_slice(encoded);
+        }
         let mut luni = (units.len() as u32).to_be_bytes().to_vec();
         luni.extend(units.iter().flat_map(|u| u.to_be_bytes()));
         block(&mut extra, b"luni", &luni)?;

crates/render/src/encode/tests_psd.rs

@@ -321,3 +321,12 @@ fn the_profile_and_the_size_limit() {
     let err = Renderer::new().export_region(&doc, doc.artboards[0].rect, RasterFormat::Psd, &o).unwrap_err();
     assert!(err.contains(&MAX_SIDE.to_string()), "{err}");
 }
+
+#[test]
+fn long_unicode_name_is_cut_on_a_character_boundary() {
+    let mut b = DocBuilder::new(100.0, 60.0);
+    b.layer(&("a".repeat(254) + "😀"));
+    b.rect(Rect::new(0.0, 0.0, 5.0, 5.0), Color::rgb8(0, 0, 0), |_| {});
+    let file = export(&b.build(), &opts(PsdOptions::default()));
+    assert_eq!(parse(&file).records.last().unwrap().name, "a".repeat(254));
+}