From 6d49a690bb22fcec30614ef30156242ba0ececd5 Mon Sep 17 00:00:00 2001
From: Steve Canny <stcanny@gmail.com>
Date: Sun, 28 Apr 2024 17:39:35 -0700
Subject: [PATCH] rfctr(table): reimplement CT_Tc._tr_above

Use XPath rather than oxml structures.
---
 src/docx/oxml/table.py | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/src/docx/oxml/table.py b/src/docx/oxml/table.py
index ddebee71b..963f3ebf7 100644
--- a/src/docx/oxml/table.py
+++ b/src/docx/oxml/table.py
@@ -748,11 +748,10 @@ def _tr_above(self) -> CT_Row:
 
         Raises |ValueError| if called on a cell in the top-most row.
         """
-        tr_lst = self._tbl.tr_lst
-        tr_idx = tr_lst.index(self._tr)
-        if tr_idx == 0:
-            raise ValueError("no tr above topmost tr")
-        return tr_lst[tr_idx - 1]
+        tr_aboves = self.xpath("./ancestor::w:tr[position()=1]/preceding-sibling::w:tr[1]")
+        if not tr_aboves:
+            raise ValueError("no tr above topmost tr in w:tbl")
+        return tr_aboves[0]
 
     @property
     def _tr_below(self) -> CT_Row | None: