Avoid Allocating RowDimension Unneccesarily

src/PhpSpreadsheet/Worksheet/AutoFilter.php

@@ -1049,7 +1049,11 @@ public function showHideRows()
                 }
             }
             //    Set show/hide for the row based on the result of the autoFilter result
-            $this->workSheet->getRowDimension((int) $row)->setVisible($result);
+            //    If the RowDimension object has not been allocated yet and the row should be visible,
+            //    then we can avoid any operation since the rows are visible by default (saves a lot of memory)
+            if ($result === false || $this->workSheet->rowDimensionExists((int) $row)) {
+                $this->workSheet->getRowDimension((int) $row)->setVisible($result);
+            }
         }
         $this->evaluated = true;
 

src/PhpSpreadsheet/Worksheet/Worksheet.php

@@ -3875,4 +3875,9 @@ public static function nameRequiresQuotes(string $sheetName): bool
     {
         return preg_match(self::SHEET_NAME_REQUIRES_NO_QUOTES, $sheetName) !== 1;
     }
+
+    public function isRowVisible(int $row): bool
+    {
+        return !$this->rowDimensionExists($row) || $this->getRowDimension($row)->getVisible();
+    }
 }

src/PhpSpreadsheet/Writer/Html.php

@@ -504,7 +504,7 @@ public function generateSheetData()
                 $html .= $startTag;
 
                 // Write row if there are HTML table cells in it
-                $mpdfInvisible = $this->isMPdf && $sheet->getRowDimension($row)->getVisible() === false;
+                $mpdfInvisible = $this->isMPdf && !$sheet->isRowVisible($row);
                 if (!$mpdfInvisible && !isset($this->isSpannedRow[$sheet->getParent()->getIndex($sheet)][$row])) {
                     // Start a new rowData
                     $rowData = [];

src/PhpSpreadsheet/Writer/Ods/Content.php

@@ -171,7 +171,7 @@ private function writeRows(XMLWriter $objWriter, Worksheet $sheet, int $sheetInd
                     $objWriter->endElement();
                     $span_row = 0;
                 } else {
-                    if ($sheet->getRowDimension($row->getRowIndex())->getRowHeight() > 0) {
+                    if ($sheet->rowDimensionExists($row->getRowIndex()) && $sheet->getRowDimension($row->getRowIndex())->getRowHeight() > 0) {
                         $objWriter->writeAttribute(
                             'table:style-name',
                             sprintf('%s_%d_%d', Style::ROW_STYLE_PREFIX, $sheetIndex, $row->getRowIndex())

src/PhpSpreadsheet/Writer/Xlsx/Worksheet.php

@@ -13,6 +13,7 @@
 use PhpOffice\PhpSpreadsheet\Style\Conditional;
 use PhpOffice\PhpSpreadsheet\Style\ConditionalFormatting\ConditionalDataBar;
 use PhpOffice\PhpSpreadsheet\Style\ConditionalFormatting\ConditionalFormattingRuleExtension;
+use PhpOffice\PhpSpreadsheet\Worksheet\RowDimension;
 use PhpOffice\PhpSpreadsheet\Worksheet\SheetView;
 use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet as PhpspreadsheetWorksheet;
 
@@ -1143,11 +1144,12 @@ private function writeSheetData(XMLWriter $objWriter, PhpspreadsheetWorksheet $w
         }
 
         $currentRow = 0;
+        $emptyDimension = new RowDimension();
         while ($currentRow++ < $highestRow) {
             $isRowSet = isset($cellsByRow[$currentRow]);
             if ($isRowSet || $worksheet->rowDimensionExists($currentRow)) {
                 // Get row dimension
-                $rowDimension = $worksheet->getRowDimension($currentRow);
+                $rowDimension = $worksheet->rowDimensionExists($currentRow) ? $worksheet->getRowDimension($currentRow) : $emptyDimension;
 
                 // Write current row?
                 $writeCurrentRow = $isRowSet || $rowDimension->getRowHeight() >= 0 || $rowDimension->getVisible() === false || $rowDimension->getCollapsed() === true || $rowDimension->getOutlineLevel() > 0 || $rowDimension->getXfIndex() !== null;

tests/PhpSpreadsheetTests/Worksheet/AutoFilter/AutoFilterCustomNumericTest.php

@@ -95,6 +95,7 @@ public function testEqualsListSimple(): void
     public function testEqualsList(): void
     {
         $sheet = $this->initSheet();
+        $sheet->getRowDimension(4)->setRowHeight(25);
         $maxRow = $this->maxRow;
         $autoFilter = $sheet->getAutoFilter();
         $autoFilter->setRange("A1:A$maxRow");
@@ -115,6 +116,17 @@ public function testEqualsList(): void
             ->setRuleType(Rule::AUTOFILTER_RULETYPE_CUSTOMFILTER);
 
         self::assertEquals([3, 4, 9, 10], $this->getVisible());
+        self::assertTrue($sheet->rowDimensionExists(2));
+        self::assertFalse($sheet->rowDimensionExists(3), 'row visible by default');
+        self::assertTrue($sheet->rowDimensionExists(4), 'row is visible but height has been set');
+        self::assertTrue($sheet->rowDimensionExists(5));
+        self::assertTrue($sheet->rowDimensionExists(6));
+        self::assertTrue($sheet->rowDimensionExists(7));
+        self::assertTrue($sheet->rowDimensionExists(8));
+        self::assertFalse($sheet->rowDimensionExists(9), 'row visible by default');
+        self::assertFalse($sheet->rowDimensionExists(10), 'row visible by default');
+        self::assertTrue($sheet->rowDimensionExists(11));
+        self::assertTrue($sheet->rowDimensionExists(12));
     }
 
     public function testNotEqualsList(): void

tests/PhpSpreadsheetTests/Worksheet/AutoFilter/SetupTeardown.php

@@ -62,7 +62,7 @@ public function getVisibleSheet(Worksheet $sheet): array
         $sheet->getAutoFilter()->showHideRows();
         $actualVisible = [];
         for ($row = 2; $row <= $this->maxRow; ++$row) {
-            if ($sheet->getRowDimension($row)->getVisible()) {
+            if ($sheet->isRowVisible($row)) {
                 $actualVisible[] = $row;
             }
         }

tests/PhpSpreadsheetTests/Worksheet/RowDimensionSaveTest.php

@@ -0,0 +1,55 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Worksheet;
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+use PhpOffice\PhpSpreadsheet\Writer\Pdf\Mpdf;
+use PhpOffice\PhpSpreadsheetTests\Functional\AbstractFunctional;
+
+class RowDimensionSaveTest extends AbstractFunctional
+{
+    /**
+     * @dataProvider typeProvider
+     */
+    public function testSaveNoAllocateRowDimension(string $type): void
+    {
+        $spreadsheet = new Spreadsheet();
+        $sheet = $spreadsheet->getActiveSheet();
+        $sheet->getCell('A1')->setValue(1);
+        $sheet->getCell('A2')->setValue(2);
+        $sheet->getCell('A3')->setValue(3);
+        $sheet->getRowDimension(2)->setVisible(false);
+        $reloadedSpreadsheet = $this->writeAndReload($spreadsheet, $type);
+        self::assertFalse($sheet->rowDimensionExists(1));
+        self::assertTrue($sheet->rowDimensionExists(2));
+        self::assertFalse($sheet->rowDimensionExists(3));
+        $spreadsheet->disconnectWorksheets();
+        $reloadedSpreadsheet->disconnectWorksheets();
+    }
+
+    public static function typeProvider(): array
+    {
+        return [
+            ['Xlsx'],
+            ['Xls'],
+            ['Ods'],
+            ['Html'],
+        ];
+    }
+
+    public function testSaveNoAllocateRowDimensionMpdf(): void
+    {
+        $spreadsheet = new Spreadsheet();
+        $sheet = $spreadsheet->getActiveSheet();
+        $sheet->getCell('A1')->setValue(1);
+        $sheet->getCell('A2')->setValue(2);
+        $sheet->getCell('A3')->setValue(3);
+        $sheet->getRowDimension(2)->setVisible(false);
+        $writer = new Mpdf($spreadsheet);
+        $writer->generateHtmlAll();
+        self::assertFalse($sheet->rowDimensionExists(1));
+        self::assertTrue($sheet->rowDimensionExists(2));
+        self::assertFalse($sheet->rowDimensionExists(3));
+        $spreadsheet->disconnectWorksheets();
+    }
+}