tdf#96475 sort error result between text and empty cell

Error results weren't handled at all and sorted same as numeric 0, which
due to "stable sort" resulted in arbitrary looking sort order if 0
values or results where included.

Change-Id: Ib7c516b57ea92bc5b813f448d9c2bb5491e43940

sc/source/core/data/table3.cxx

@@ -1483,12 +1483,35 @@ short ScTable::CompareCell(
     {
         if (!rCell2.isEmpty())
         {
+            bool bErr1 = false;
             bool bStr1 = ( eType1 != CELLTYPE_VALUE );
-            if (eType1 == CELLTYPE_FORMULA && rCell1.mpFormula->IsValue())
-                bStr1 = false;
+            if (eType1 == CELLTYPE_FORMULA)
+            {
+                if (rCell1.mpFormula->GetErrCode() != FormulaError::NONE)
+                {
+                    bErr1 = true;
+                    bStr1 = false;
+                }
+                else if (rCell1.mpFormula->IsValue())
+                {
+                    bStr1 = false;
+                }
+            }
+
+            bool bErr2 = false;
             bool bStr2 = ( eType2 != CELLTYPE_VALUE );
-            if (eType2 == CELLTYPE_FORMULA && rCell2.mpFormula->IsValue())
-                bStr2 = false;
+            if (eType2 == CELLTYPE_FORMULA)
+            {
+                if (rCell2.mpFormula->GetErrCode() != FormulaError::NONE)
+                {
+                    bErr2 = true;
+                    bStr2 = false;
+                }
+                else if (rCell2.mpFormula->IsValue())
+                {
+                    bStr2 = false;
+                }
+            }
 
             if ( bStr1 && bStr2 )           // only compare strings as strings!
             {
@@ -1531,10 +1554,32 @@ short ScTable::CompareCell(
                         nRes = static_cast<short>( pSortCollator->compareString( aStr1, aStr2 ) );
                 }
             }
-            else if ( bStr1 )               // String <-> Number
-                nRes = 1;                   // Number in front
-            else if ( bStr2 )               // Number <-> String
-                nRes = -1;                  // Number in front
+            else if ( bStr1 )               // String <-> Number or Error
+            {
+                if (bErr2)
+                    nRes = -1;              // String in front of Error
+                else
+                    nRes = 1;               // Number in front of String
+            }
+            else if ( bStr2 )               // Number or Error <-> String
+            {
+                if (bErr1)
+                    nRes = 1;               // String in front of Error
+                else
+                    nRes = -1;              // Number in front of String
+            }
+            else if (bErr1 && bErr2)
+            {
+                // nothing, two Errors are equal
+            }
+            else if (bErr1)                 // Error <-> Number
+            {
+                nRes = 1;                   // Number in front of Error
+            }
+            else if (bErr2)                 // Number <-> Error
+            {
+                nRes = -1;                  // Number in front of Error
+            }
             else                            // Mixed numbers
             {
                 double nVal1 = rCell1.getValue();