From 74fa69f20dc45a2261e8221da63f0318d90f337c Mon Sep 17 00:00:00 2001
From: Yonghye Kwon <developer.0hye@gmail.com>
Date: Sat, 29 Aug 2026 14:30:27 +0700
Subject: [PATCH] fix: preserve row thickTop

Signed-off-by: Yonghye Kwon <developer.0hye@gmail.com>
---
 src/structs/row.rs        | 25 +++++++++++++++++++++++++
 tests/integration_test.rs | 22 ++++++++++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/src/structs/row.rs b/src/structs/row.rs
index 006f204b..975a056b 100644
--- a/src/structs/row.rs
+++ b/src/structs/row.rs
@@ -38,6 +38,7 @@ pub struct Row {
     row_num:       UInt32Value,
     height:        DoubleValue,
     descent:       DoubleValue,
+    thick_top:     BooleanValue,
     thick_bot:     BooleanValue,
     custom_height: BooleanValue,
     hidden:        BooleanValue,
@@ -50,6 +51,7 @@ impl Default for Row {
             row_num:       UInt32Value::default(),
             height:        DoubleValue::default(),
             descent:       DoubleValue::default(),
+            thick_top:     BooleanValue::default(),
             thick_bot:     BooleanValue::default(),
             custom_height: BooleanValue::default(),
             hidden:        BooleanValue::default(),
@@ -116,6 +118,25 @@ impl Row {
         self
     }
 
+    #[inline]
+    #[must_use]
+    pub fn thick_top(&self) -> bool {
+        self.thick_top.value()
+    }
+
+    #[inline]
+    #[must_use]
+    #[deprecated(since = "3.0.0", note = "Use thick_top()")]
+    pub fn get_thick_top(&self) -> bool {
+        self.thick_top()
+    }
+
+    #[inline]
+    pub fn set_thick_top(&mut self, value: bool) -> &mut Self {
+        self.thick_top.set_value(value);
+        self
+    }
+
     #[inline]
     #[must_use]
     pub fn thick_bot(&self) -> bool {
@@ -221,6 +242,7 @@ impl Row {
     ) {
         set_string_from_xml!(self, e, row_num, "r");
         set_string_from_xml!(self, e, height, "ht");
+        set_string_from_xml!(self, e, thick_top, "thickTop");
         set_string_from_xml!(self, e, thick_bot, "thickBot");
         set_string_from_xml!(self, e, custom_height, "customHeight");
         set_string_from_xml!(self, e, hidden, "hidden");
@@ -300,6 +322,9 @@ impl Row {
         if self.height.value() != 0f64 {
             attributes.push(("ht", &height).into());
         }
+        if self.thick_top.value() {
+            attributes.push(("thickTop", self.thick_top.value_string()).into());
+        }
         if self.thick_bot.value() {
             attributes.push(("thickBot", self.thick_bot.value_string()).into());
         }
diff --git a/tests/integration_test.rs b/tests/integration_test.rs
index 913973aa..37544d68 100644
--- a/tests/integration_test.rs
+++ b/tests/integration_test.rs
@@ -2372,6 +2372,28 @@ fn zip_entry_to_string(xlsx: &[u8], entry_name: &str) -> String {
     xml
 }
 
+#[test]
+fn row_thick_top_roundtrips() {
+    let mut book = new_file();
+    let sheet = book.sheet_mut(0).unwrap();
+    sheet.cell_mut("A2").set_value("thick top");
+    sheet.row_dimension_mut(2).set_thick_top(true);
+
+    let xlsx = workbook_to_xlsx_bytes(&book);
+    let sheet_xml = zip_entry_to_string(&xlsx, "xl/worksheets/sheet1.xml");
+    assert!(sheet_xml.contains("thickTop=\"1\""));
+
+    let roundtrip = reader::xlsx::read_reader(std::io::Cursor::new(xlsx), true).unwrap();
+    assert!(
+        roundtrip
+            .sheet(0)
+            .unwrap()
+            .row_dimension(2)
+            .unwrap()
+            .thick_top()
+    );
+}
+
 fn cell_fragment(sheet_xml: &str, coordinate: &str) -> String {
     let start = sheet_xml
         .find(&format!("<c r=\"{coordinate}\""))