From f1421b2b80e3eafd9da49e278e05b55e5fd6466d Mon Sep 17 00:00:00 2001
From: wp_xxyyzz <wp_xxyyzz@8e941d3f-bd1b-0410-a28a-d453659cc2b4>
Date: Wed, 1 Jul 2020 16:26:01 +0000
Subject: [PATCH] fpspreadsheet: Fix ooxml writer for conditional formatting
 broken in one of previous commits.

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@7513 8e941d3f-bd1b-0410-a28a-d453659cc2b4
---
 components/fpspreadsheet/source/common/xlsxooxml.pas | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/components/fpspreadsheet/source/common/xlsxooxml.pas b/components/fpspreadsheet/source/common/xlsxooxml.pas
index b6b813468..219ed3cd5 100644
--- a/components/fpspreadsheet/source/common/xlsxooxml.pas
+++ b/components/fpspreadsheet/source/common/xlsxooxml.pas
@@ -391,6 +391,8 @@ const
   );
 
 function CFOperandToStr(v: Variant): String;
+const
+  ERR = cardinal(-1);
 var
   r, c: Cardinal;
 begin
@@ -401,7 +403,7 @@ begin
   if Result[1] = '=' then
     Delete(Result, 1, 1)
   else
-  if ParseCellString(Result, r, c) then
+  if ParseCellString(Result, r, c) and (r <> ERR) and (c <> ERR) then
     Result := GetCellString(r, c, [])
   else
   if VarIsStr(v) then