From 306eb9029618b81f45dd098a62b759020aa038af Mon Sep 17 00:00:00 2001
From: OssianEPPlus <122265629+OssianEPPlus@users.noreply.github.com>
Date: Mon, 27 May 2024 15:08:03 +0200
Subject: [PATCH] Added fix for empty worksheet (#1463)

* Added fix for empty worksheet

* Fixed short minValue to int MinValue
---
 .../FormulaExpressions/RangeExpression.cs      | 18 ++++++++++++------
 .../IntegrationTests/FormulaParserTests.cs     | 15 +++++++++++++++
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/src/EPPlus/FormulaParsing/FormulaExpressions/RangeExpression.cs b/src/EPPlus/FormulaParsing/FormulaExpressions/RangeExpression.cs
index e9987790f..9f1f29008 100644
--- a/src/EPPlus/FormulaParsing/FormulaExpressions/RangeExpression.cs
+++ b/src/EPPlus/FormulaParsing/FormulaExpressions/RangeExpression.cs
@@ -22,7 +22,7 @@ internal RangeExpression(FormulaRangeAddress address) : base(address._context)
         }
         public RangeExpression(string address, ParsingContext ctx, short externalReferenceIx, int worksheetIx) : base(ctx)
         {
-            _addressInfo = new FormulaRangeAddress(ctx) { ExternalReferenceIx= externalReferenceIx, WorksheetIx = worksheetIx < 0 ? ctx.CurrentCell.WorksheetIx : worksheetIx };
+            _addressInfo = new FormulaRangeAddress(ctx) { ExternalReferenceIx= externalReferenceIx, WorksheetIx = worksheetIx == int.MinValue ? ctx.CurrentCell.WorksheetIx : worksheetIx };
             ExcelCellBase.GetRowColFromAddress(address, out int fromRow, out int fromCol, out int toRow, out int toCol, out bool fixedFromRow, out bool fixedFromCol, out bool fixedToRow, out bool fixedToCol);
             _addressInfo.FromRow = fromRow==0 ? 1 : fromRow;
             _addressInfo.ToRow = toRow == 0 ? ExcelPackage.MaxRows : toRow;
@@ -39,11 +39,17 @@ public override CompileResult Compile()
                 {
                     if (_addressInfo.IsSingleCell)
                     {
-
-                        var ws = Context.Package.Workbook.GetWorksheetByIndexInList(_addressInfo.WorksheetIx);
-                        var v = ws.GetValue(_addressInfo.FromRow, _addressInfo.FromCol); //Use GetValue to get richtext values.
-                        _cachedCompileResult = CompileResultFactory.Create(v, _addressInfo);
-                        _cachedCompileResult.IsHiddenCell = ws.IsRowHidden(_addressInfo.FromRow);
+                        if (_addressInfo.WorksheetIx == -1)
+                        {
+                            _cachedCompileResult = CompileResult.GetErrorResult(eErrorType.Ref);
+                        }
+                        else
+                        {
+                            var ws = Context.Package.Workbook.GetWorksheetByIndexInList(_addressInfo.WorksheetIx);
+                            var v = ws.GetValue(_addressInfo.FromRow, _addressInfo.FromCol); //Use GetValue to get richtext values.
+                            _cachedCompileResult = CompileResultFactory.Create(v, _addressInfo);
+                            _cachedCompileResult.IsHiddenCell = ws.IsRowHidden(_addressInfo.FromRow);
+                        }
                     }
                     else
                     {
diff --git a/src/EPPlusTest/FormulaParsing/IntegrationTests/FormulaParserTests.cs b/src/EPPlusTest/FormulaParsing/IntegrationTests/FormulaParserTests.cs
index d26eb0b90..2e9b5692a 100644
--- a/src/EPPlusTest/FormulaParsing/IntegrationTests/FormulaParserTests.cs
+++ b/src/EPPlusTest/FormulaParsing/IntegrationTests/FormulaParserTests.cs
@@ -73,5 +73,20 @@ string QStr(string s)
             char quotechar = '\"';
             return $"{quotechar}{s}{quotechar}";
         }
+        [TestMethod]
+        public void ReferencingWorksheetThatDoesNotExistShouldReturnRef()
+        {
+            using (ExcelPackage p = new ExcelPackage())
+            {
+                ExcelWorksheet ws = p.Workbook.Worksheets.Add("sheet1");
+
+                ws.Cells["A1"].Formula = "Sheet2!A1";
+
+                ws.Calculate();
+
+                var value = ws.Cells["A1"].Value;
+                Assert.AreEqual(ErrorValues.RefError, value);
+            }
+        }
     }
 }