From c3f3b76ac2815899d1d14f834bb882eb413cc7f6 Mon Sep 17 00:00:00 2001
From: rootsec1 <nateriver210@gmail.com>
Date: Tue, 14 Apr 2026 17:48:40 -0400
Subject: [PATCH] Fix worksheet dimension after cell writes

---
 sheet.go      | 39 +++++++++++++++++++++++++++++++++++++++
 sheet_test.go | 28 +++++++++++++++++++++++++++-
 2 files changed, 66 insertions(+), 1 deletion(-)

diff --git a/sheet.go b/sheet.go
index dc41783c48..140c0c0aa7 100644
--- a/sheet.go
+++ b/sheet.go
@@ -2104,6 +2104,45 @@ func (ws *xlsxWorksheet) prepareSheetXML(col, row int) {
 	}
 	rowData := &ws.SheetData.Row[row-1]
 	fillColumns(rowData, col, row)
+	ws.expandSheetDimension(col, row)
+}
+
+func (ws *xlsxWorksheet) expandSheetDimension(col, row int) {
+	if col < 1 || row < 1 {
+		return
+	}
+	cell, err := CoordinatesToCellName(col, row)
+	if err != nil {
+		return
+	}
+	if ws.Dimension == nil || ws.Dimension.Ref == "" {
+		ws.Dimension = &xlsxDimension{Ref: cell}
+		return
+	}
+	coordinates, err := rangeRefToCoordinates(ws.Dimension.Ref)
+	if err != nil {
+		ws.Dimension = &xlsxDimension{Ref: cell}
+		return
+	}
+	_ = sortCoordinates(coordinates)
+	if col < coordinates[0] {
+		coordinates[0] = col
+	}
+	if row < coordinates[1] {
+		coordinates[1] = row
+	}
+	if col > coordinates[2] {
+		coordinates[2] = col
+	}
+	if row > coordinates[3] {
+		coordinates[3] = row
+	}
+	ref, err := coordinatesToRangeRef(coordinates)
+	if err != nil {
+		ws.Dimension = &xlsxDimension{Ref: cell}
+		return
+	}
+	ws.Dimension = &xlsxDimension{Ref: ref}
 }
 
 // fillColumns fill cells in the column of the row as contiguous.
diff --git a/sheet_test.go b/sheet_test.go
index bb91f2c5a9..d859c337da 100644
--- a/sheet_test.go
+++ b/sheet_test.go
@@ -513,13 +513,14 @@ func TestWorksheetWriter(t *testing.T) {
 	// Test set cell value with alternate content
 	f.Sheet.Delete("xl/worksheets/sheet1.xml")
 	worksheet := xml.Header + `<worksheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships"><sheetData><row r="1"><c r="A1"><v>%d</v></c></row></sheetData><mc:AlternateContent xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"><mc:Choice xmlns:a14="http://schemas.microsoft.com/office/drawing/2010/main" Requires="a14"><xdr:twoCellAnchor editAs="oneCell"></xdr:twoCellAnchor></mc:Choice><mc:Fallback/></mc:AlternateContent></worksheet>`
+	updatedWorksheet := xml.Header + `<worksheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships"><dimension ref="A1"></dimension><sheetData><row r="1"><c r="A1"><v>%d</v></c></row></sheetData><mc:AlternateContent xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"><mc:Choice xmlns:a14="http://schemas.microsoft.com/office/drawing/2010/main" Requires="a14"><xdr:twoCellAnchor editAs="oneCell"></xdr:twoCellAnchor></mc:Choice><mc:Fallback/></mc:AlternateContent></worksheet>`
 	f.Pkg.Store("xl/worksheets/sheet1.xml", []byte(fmt.Sprintf(worksheet, 1)))
 	f.checked = sync.Map{}
 	assert.NoError(t, f.SetCellValue("Sheet1", "A1", 2))
 	f.workSheetWriter()
 	value, ok := f.Pkg.Load("xl/worksheets/sheet1.xml")
 	assert.True(t, ok)
-	assert.Equal(t, fmt.Sprintf(worksheet, 2), string(value.([]byte)))
+	assert.Equal(t, fmt.Sprintf(updatedWorksheet, 2), string(value.([]byte)))
 }
 
 func TestGetWorkbookPath(t *testing.T) {
@@ -840,6 +841,31 @@ func TestSheetDimension(t *testing.T) {
 	assert.Empty(t, dimension)
 	assert.Equal(t, err, ErrSheetNameBlank)
 
+	f = NewFile()
+	assert.NoError(t, f.SetCellValue(sheetName, "C5", "value"))
+	dimension, err = f.GetSheetDimension(sheetName)
+	assert.NoError(t, err)
+	assert.Equal(t, "C5", dimension)
+
+	filePath := filepath.Join(t.TempDir(), "sheet-dimension.xlsx")
+	assert.NoError(t, f.SaveAs(filePath))
+	assert.NoError(t, f.Close())
+
+	f, err = OpenFile(filePath)
+	assert.NoError(t, err)
+	dimension, err = f.GetSheetDimension(sheetName)
+	assert.NoError(t, err)
+	assert.Equal(t, "C5", dimension)
+	assert.NoError(t, f.Close())
+
+	f = NewFile()
+	assert.NoError(t, f.SetSheetDimension(sheetName, "B2:E61"))
+	assert.NoError(t, f.SetCellValue(sheetName, "G64", "value"))
+	dimension, err = f.GetSheetDimension(sheetName)
+	assert.NoError(t, err)
+	assert.Equal(t, "B2:G64", dimension)
+	assert.NoError(t, f.Close())
+
 	// Test get the worksheet dimension with in mode
 	f, err = OpenFile(filepath.Join("test", "Book1.xlsx"), Options{UnzipXMLSizeLimit: 128})
 	assert.NoError(t, err)