diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index 6390e0fc21..f96562615c 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -2825,91 +2825,6 @@ parameters:
 			count: 1
 			path: src/PhpSpreadsheet/Reader/Csv/Delimiter.php
 
-		-
-			message: "#^Property PhpOffice\\\\PhpSpreadsheet\\\\Reader\\\\Gnumeric\\:\\:\\$referenceHelper has no typehint specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Reader/Gnumeric.php
-
-		-
-			message: "#^Parameter \\#1 \\$fp of function fread expects resource, resource\\|false given\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Reader/Gnumeric.php
-
-		-
-			message: "#^Parameter \\#1 \\$fp of function fclose expects resource, resource\\|false given\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Reader/Gnumeric.php
-
-		-
-			message: "#^Property PhpOffice\\\\PhpSpreadsheet\\\\Reader\\\\Gnumeric\\:\\:\\$mappings has no typehint specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Reader/Gnumeric.php
-
-		-
-			message: "#^Offset 'No' does not exist on SimpleXMLElement\\|null\\.$#"
-			count: 2
-			path: src/PhpSpreadsheet/Reader/Gnumeric.php
-
-		-
-			message: "#^Offset 'Unit' does not exist on SimpleXMLElement\\|null\\.$#"
-			count: 2
-			path: src/PhpSpreadsheet/Reader/Gnumeric.php
-
-		-
-			message: "#^Cannot call method setWidth\\(\\) on PhpOffice\\\\PhpSpreadsheet\\\\Worksheet\\\\ColumnDimension\\|null\\.$#"
-			count: 3
-			path: src/PhpSpreadsheet/Reader/Gnumeric.php
-
-		-
-			message: "#^Cannot call method setVisible\\(\\) on PhpOffice\\\\PhpSpreadsheet\\\\Worksheet\\\\ColumnDimension\\|null\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Reader/Gnumeric.php
-
-		-
-			message: "#^Offset 'DefaultSizePts' does not exist on SimpleXMLElement\\|null\\.$#"
-			count: 2
-			path: src/PhpSpreadsheet/Reader/Gnumeric.php
-
-		-
-			message: "#^Cannot call method setRowHeight\\(\\) on PhpOffice\\\\PhpSpreadsheet\\\\Worksheet\\\\RowDimension\\|null\\.$#"
-			count: 2
-			path: src/PhpSpreadsheet/Reader/Gnumeric.php
-
-		-
-			message: "#^Cannot call method setVisible\\(\\) on PhpOffice\\\\PhpSpreadsheet\\\\Worksheet\\\\RowDimension\\|null\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Reader/Gnumeric.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Reader\\\\Gnumeric\\:\\:parseBorderAttributes\\(\\) has no return typehint specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Reader/Gnumeric.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Reader\\\\Gnumeric\\:\\:parseBorderAttributes\\(\\) has parameter \\$borderAttributes with no typehint specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Reader/Gnumeric.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Reader\\\\Gnumeric\\:\\:parseRichText\\(\\) has no return typehint specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Reader/Gnumeric.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Reader\\\\Gnumeric\\:\\:parseRichText\\(\\) has parameter \\$is with no typehint specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Reader/Gnumeric.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Reader\\\\Gnumeric\\:\\:parseGnumericColour\\(\\) has no return typehint specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Reader/Gnumeric.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Reader\\\\Gnumeric\\:\\:parseGnumericColour\\(\\) has parameter \\$gnmColour with no typehint specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Reader/Gnumeric.php
-
 		-
 			message: "#^Property PhpOffice\\\\PhpSpreadsheet\\\\Reader\\\\Html\\:\\:\\$rowspan has no typehint specified\\.$#"
 			count: 1
@@ -8325,11 +8240,6 @@ parameters:
 			count: 1
 			path: tests/PhpSpreadsheetTests/Reader/CsvTest.php
 
-		-
-			message: "#^Cannot call method getVisible\\(\\) on PhpOffice\\\\PhpSpreadsheet\\\\Worksheet\\\\RowDimension\\|null\\.$#"
-			count: 1
-			path: tests/PhpSpreadsheetTests/Reader/Gnumeric/GnumericLoadTest.php
-
 		-
 			message: "#^Cannot call method getRowHeight\\(\\) on PhpOffice\\\\PhpSpreadsheet\\\\Worksheet\\\\RowDimension\\|null\\.$#"
 			count: 2
diff --git a/src/PhpSpreadsheet/Reader/Gnumeric.php b/src/PhpSpreadsheet/Reader/Gnumeric.php
index d3cdf1b002..7086cc6358 100644
--- a/src/PhpSpreadsheet/Reader/Gnumeric.php
+++ b/src/PhpSpreadsheet/Reader/Gnumeric.php
@@ -25,7 +25,19 @@
 
 class Gnumeric extends BaseReader
 {
-    private const UOM_CONVERSION_POINTS_TO_CENTIMETERS = 0.03527777778;
+    const NAMESPACE_GNM = 'http://www.gnumeric.org/v10.dtd'; // gmr in old sheets
+
+    const NAMESPACE_XSI = 'http://www.w3.org/2001/XMLSchema-instance';
+
+    const NAMESPACE_OFFICE = 'urn:oasis:names:tc:opendocument:xmlns:office:1.0';
+
+    const NAMESPACE_XLINK = 'http://www.w3.org/1999/xlink';
+
+    const NAMESPACE_DC = 'http://purl.org/dc/elements/1.1/';
+
+    const NAMESPACE_META = 'urn:oasis:names:tc:opendocument:xmlns:meta:1.0';
+
+    const NAMESPACE_OOO = 'http://openoffice.org/2004/office';
 
     /**
      * Shared Expressions.
@@ -41,16 +53,9 @@ class Gnumeric extends BaseReader
      */
     private $spreadsheet;
 
+    /** @var ReferenceHelper */
     private $referenceHelper;
 
-    /**
-     * Namespace shared across all functions.
-     * It is 'gnm', except for really old sheets which use 'gmr'.
-     *
-     * @var string
-     */
-    private $gnm = 'gnm';
-
     /**
      * Create a new Gnumeric.
      */
@@ -77,8 +82,10 @@ public function canRead($pFilename)
         if (function_exists('gzread')) {
             // Read signature data (first 3 bytes)
             $fh = fopen($pFilename, 'rb');
-            $data = fread($fh, 2);
-            fclose($fh);
+            if ($fh !== false) {
+                $data = fread($fh, 2);
+                fclose($fh);
+            }
         }
 
         return $data == chr(0x1F) . chr(0x8B);
@@ -86,7 +93,7 @@ public function canRead($pFilename)
 
     private static function matchXml(string $name, string $field): bool
     {
-        return 1 === preg_match("/^(gnm|gmr):$field$/", $name);
+        return 1 === preg_match("/:$field$/", $name);
     }
 
     /**
@@ -188,6 +195,7 @@ private function gzfileGetContents($filename)
         return $data;
     }
 
+    /** @var array */
     private static $mappings = [
         'borderStyle' => [
             '0' => Border::BORDER_NONE,
@@ -266,7 +274,7 @@ public static function gnumericMappings(): array
     private function processComments(SimpleXMLElement $sheet): void
     {
         if ((!$this->readDataOnly) && (isset($sheet->Objects))) {
-            foreach ($sheet->Objects->children($this->gnm, true) as $key => $comment) {
+            foreach ($sheet->Objects->children(self::NAMESPACE_GNM) as $key => $comment) {
                 $commentAttributes = $comment->attributes();
                 //    Only comment objects are handled at the moment
                 if ($commentAttributes->Text) {
@@ -276,6 +284,14 @@ private function processComments(SimpleXMLElement $sheet): void
         }
     }
 
+    /**
+     * @param mixed $value
+     */
+    private function testSimpleXml($value): SimpleXMLElement
+    {
+        return ($value instanceof SimpleXMLElement) ? $value : new SimpleXMLElement('<?xml version="1.0" encoding="UTF-8"?><root></root>');
+    }
+
     /**
      * Loads Spreadsheet from file.
      *
@@ -304,12 +320,10 @@ public function loadIntoExisting(string $pFilename, Spreadsheet $spreadsheet): S
         $gFileData = $this->gzfileGetContents($pFilename);
 
         $xml2 = simplexml_load_string($this->securityScanner->scan($gFileData), 'SimpleXMLElement', Settings::getLibXmlLoaderOptions());
-        $xml = ($xml2 !== false) ? $xml2 : new SimpleXMLElement('<?xml version="1.0" encoding="UTF-8"?><root></root>');
-        $namespacesMeta = $xml->getNamespaces(true);
-        $this->gnm = array_key_exists('gmr', $namespacesMeta) ? 'gmr' : 'gnm';
+        $xml = self::testSimpleXml($xml2);
 
-        $gnmXML = $xml->children($namespacesMeta[$this->gnm]);
-        (new Properties($this->spreadsheet))->readProperties($xml, $gnmXML, $namespacesMeta);
+        $gnmXML = $xml->children(self::NAMESPACE_GNM);
+        (new Properties($this->spreadsheet))->readProperties($xml, $gnmXML);
 
         $worksheetID = 0;
         foreach ($gnmXML->Sheets->Sheet as $sheet) {
@@ -329,7 +343,7 @@ public function loadIntoExisting(string $pFilename, Spreadsheet $spreadsheet): S
             $this->spreadsheet->getActiveSheet()->setTitle($worksheetName, false, false);
 
             if (!$this->readDataOnly) {
-                (new PageSetup($this->spreadsheet, $this->gnm))
+                (new PageSetup($this->spreadsheet))
                     ->printInformation($sheet)
                     ->sheetMargins($sheet);
             }
@@ -510,21 +524,37 @@ private function processMergedCells(SimpleXMLElement $sheet): void
         }
     }
 
+    private function setColumnWidth(int $c, float $defaultWidth): void
+    {
+        $colDim = $this->spreadsheet->getActiveSheet()->getColumnDimension(Coordinate::stringFromColumnIndex($c + 1));
+        if ($colDim !== null) {
+            $colDim->setWidth($defaultWidth);
+        }
+    }
+
+    private function setColumnInvisible(int $c): void
+    {
+        $colDim = $this->spreadsheet->getActiveSheet()->getColumnDimension(Coordinate::stringFromColumnIndex($c + 1));
+        if ($colDim !== null) {
+            $colDim->setVisible(false);
+        }
+    }
+
     private function processColumnLoop(int $c, int $maxCol, SimpleXMLElement $columnOverride, float $defaultWidth): int
     {
-        $columnAttributes = $columnOverride->attributes();
+        $columnAttributes = self::testSimpleXml($columnOverride->attributes());
         $column = $columnAttributes['No'];
         $columnWidth = ((float) $columnAttributes['Unit']) / 5.4;
         $hidden = (isset($columnAttributes['Hidden'])) && ((string) $columnAttributes['Hidden'] == '1');
         $columnCount = (int) ($columnAttributes['Count'] ?? 1);
         while ($c < $column) {
-            $this->spreadsheet->getActiveSheet()->getColumnDimension(Coordinate::stringFromColumnIndex($c + 1))->setWidth($defaultWidth);
+            $this->setColumnWidth($c, $defaultWidth);
             ++$c;
         }
         while (($c < ($column + $columnCount)) && ($c <= $maxCol)) {
-            $this->spreadsheet->getActiveSheet()->getColumnDimension(Coordinate::stringFromColumnIndex($c + 1))->setWidth($columnWidth);
+            $this->setColumnWidth($c, $columnWidth);
             if ($hidden) {
-                $this->spreadsheet->getActiveSheet()->getColumnDimension(Coordinate::stringFromColumnIndex($c + 1))->setVisible(false);
+                self::setColumnInvisible($c);
             }
             ++$c;
         }
@@ -536,35 +566,54 @@ private function processColumnWidths(SimpleXMLElement $sheet, int $maxCol): void
     {
         if ((!$this->readDataOnly) && (isset($sheet->Cols))) {
             //    Column Widths
+            $defaultWidth = 0;
             $columnAttributes = $sheet->Cols->attributes();
-            $defaultWidth = $columnAttributes['DefaultSizePts'] / 5.4;
+            if ($columnAttributes !== null) {
+                $defaultWidth = $columnAttributes['DefaultSizePts'] / 5.4;
+            }
             $c = 0;
             foreach ($sheet->Cols->ColInfo as $columnOverride) {
                 $c = $this->processColumnLoop($c, $maxCol, $columnOverride, $defaultWidth);
             }
             while ($c <= $maxCol) {
-                $this->spreadsheet->getActiveSheet()->getColumnDimension(Coordinate::stringFromColumnIndex($c + 1))->setWidth($defaultWidth);
+                $this->setColumnWidth($c, $defaultWidth);
                 ++$c;
             }
         }
     }
 
+    private function setRowHeight(int $r, float $defaultHeight): void
+    {
+        $rowDim = $this->spreadsheet->getActiveSheet()->getRowDimension($r);
+        if ($rowDim !== null) {
+            $rowDim->setRowHeight($defaultHeight);
+        }
+    }
+
+    private function setRowInvisible(int $r): void
+    {
+        $rowDim = $this->spreadsheet->getActiveSheet()->getRowDimension($r);
+        if ($rowDim !== null) {
+            $rowDim->setVisible(false);
+        }
+    }
+
     private function processRowLoop(int $r, int $maxRow, SimpleXMLElement $rowOverride, float $defaultHeight): int
     {
-        $rowAttributes = $rowOverride->attributes();
+        $rowAttributes = self::testSimpleXml($rowOverride->attributes());
         $row = $rowAttributes['No'];
         $rowHeight = (float) $rowAttributes['Unit'];
         $hidden = (isset($rowAttributes['Hidden'])) && ((string) $rowAttributes['Hidden'] == '1');
         $rowCount = (int) ($rowAttributes['Count'] ?? 1);
         while ($r < $row) {
             ++$r;
-            $this->spreadsheet->getActiveSheet()->getRowDimension($r)->setRowHeight($defaultHeight);
+            $this->setRowHeight($r, $defaultHeight);
         }
         while (($r < ($row + $rowCount)) && ($r < $maxRow)) {
             ++$r;
-            $this->spreadsheet->getActiveSheet()->getRowDimension($r)->setRowHeight($rowHeight);
+            $this->setRowHeight($r, $rowHeight);
             if ($hidden) {
-                $this->spreadsheet->getActiveSheet()->getRowDimension($r)->setVisible(false);
+                $this->setRowInvisible($r);
             }
         }
 
@@ -575,8 +624,11 @@ private function processRowHeights(SimpleXMLElement $sheet, int $maxRow): void
     {
         if ((!$this->readDataOnly) && (isset($sheet->Rows))) {
             //    Row Heights
+            $defaultHeight = 0;
             $rowAttributes = $sheet->Rows->attributes();
-            $defaultHeight = (float) $rowAttributes['DefaultSizePts'];
+            if ($rowAttributes !== null) {
+                $defaultHeight = (float) $rowAttributes['DefaultSizePts'];
+            }
             $r = 0;
 
             foreach ($sheet->Rows->RowInfo as $rowOverride) {
@@ -639,19 +691,21 @@ private static function addStyle2(array &$styleArray, string $key1, string $key,
         }
     }
 
-    private static function parseBorderAttributes($borderAttributes)
+    private static function parseBorderAttributes(?SimpleXMLElement $borderAttributes): array
     {
         $styleArray = [];
-        if (isset($borderAttributes['Color'])) {
-            $styleArray['color']['rgb'] = self::parseGnumericColour($borderAttributes['Color']);
-        }
+        if ($borderAttributes !== null) {
+            if (isset($borderAttributes['Color'])) {
+                $styleArray['color']['rgb'] = self::parseGnumericColour($borderAttributes['Color']);
+            }
 
-        self::addStyle($styleArray, 'borderStyle', $borderAttributes['Style']);
+            self::addStyle($styleArray, 'borderStyle', $borderAttributes['Style']);
+        }
 
         return $styleArray;
     }
 
-    private function parseRichText($is)
+    private function parseRichText(string $is): RichText
     {
         $value = new RichText();
         $value->createText($is);
@@ -659,7 +713,7 @@ private function parseRichText($is)
         return $value;
     }
 
-    private static function parseGnumericColour($gnmColour)
+    private static function parseGnumericColour(string $gnmColour): string
     {
         [$gnmR, $gnmG, $gnmB] = explode(':', $gnmColour);
         $gnmR = substr(str_pad($gnmR, 4, '0', STR_PAD_RIGHT), 0, 2);
diff --git a/src/PhpSpreadsheet/Reader/Gnumeric/PageSetup.php b/src/PhpSpreadsheet/Reader/Gnumeric/PageSetup.php
index 0fe7300593..accc27160f 100644
--- a/src/PhpSpreadsheet/Reader/Gnumeric/PageSetup.php
+++ b/src/PhpSpreadsheet/Reader/Gnumeric/PageSetup.php
@@ -2,6 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Reader\Gnumeric;
 
+use PhpOffice\PhpSpreadsheet\Reader\Gnumeric;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
 use PhpOffice\PhpSpreadsheet\Worksheet\PageMargins;
 use PhpOffice\PhpSpreadsheet\Worksheet\PageSetup as WorksheetPageSetup;
@@ -14,15 +15,9 @@ class PageSetup
      */
     private $spreadsheet;
 
-    /**
-     * @var string
-     */
-    private $gnm;
-
-    public function __construct(Spreadsheet $spreadsheet, string $gnm)
+    public function __construct(Spreadsheet $spreadsheet)
     {
         $this->spreadsheet = $spreadsheet;
-        $this->gnm = $gnm;
     }
 
     public function printInformation(SimpleXMLElement $sheet): self
@@ -68,7 +63,7 @@ public function sheetMargins(SimpleXMLElement $sheet): self
 
     private function buildMarginSet(SimpleXMLElement $sheet, array $marginSet): array
     {
-        foreach ($sheet->PrintInformation->Margins->children($this->gnm, true) as $key => $margin) {
+        foreach ($sheet->PrintInformation->Margins->children(Gnumeric::NAMESPACE_GNM) as $key => $margin) {
             $marginAttributes = $margin->attributes();
             $marginSize = ($marginAttributes['Points']) ?? 72; //    Default is 72pt
             // Convert value in points to inches
diff --git a/src/PhpSpreadsheet/Reader/Gnumeric/Properties.php b/src/PhpSpreadsheet/Reader/Gnumeric/Properties.php
index 16d9c2e082..1696f06940 100644
--- a/src/PhpSpreadsheet/Reader/Gnumeric/Properties.php
+++ b/src/PhpSpreadsheet/Reader/Gnumeric/Properties.php
@@ -2,6 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Reader\Gnumeric;
 
+use PhpOffice\PhpSpreadsheet\Reader\Gnumeric;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
 use SimpleXMLElement;
 
@@ -91,74 +92,72 @@ private function docPropertiesDC(SimpleXMLElement $officePropertyDC): void
         }
     }
 
-    private function docPropertiesMeta(SimpleXMLElement $officePropertyMeta, array $namespacesMeta): void
+    private function docPropertiesMeta(SimpleXMLElement $officePropertyMeta): void
     {
         $docProps = $this->spreadsheet->getProperties();
         foreach ($officePropertyMeta as $propertyName => $propertyValue) {
-            if ($propertyValue === null) {
-                continue;
+            if ($propertyValue !== null) {
+                $attributes = $propertyValue->attributes(Gnumeric::NAMESPACE_META);
+                $propertyValue = trim((string) $propertyValue);
+                switch ($propertyName) {
+                    case 'keyword':
+                        $docProps->setKeywords($propertyValue);
+
+                        break;
+                    case 'initial-creator':
+                        $docProps->setCreator($propertyValue);
+                        $docProps->setLastModifiedBy($propertyValue);
+
+                        break;
+                    case 'creation-date':
+                        $creationDate = strtotime($propertyValue);
+                        $creationDate = $creationDate === false ? time() : $creationDate;
+                        $docProps->setCreated($creationDate);
+                        $docProps->setModified($creationDate);
+
+                        break;
+                    case 'user-defined':
+                        [, $attrName] = explode(':', $attributes['name']);
+                        self::userDefinedProperties($attrName, $propertyValue);
+
+                        break;
+                }
             }
+        }
+    }
 
-            $attributes = $propertyValue->attributes($namespacesMeta['meta']);
-            $propertyValue = trim((string) $propertyValue);
-            switch ($propertyName) {
-                case 'keyword':
-                    $docProps->setKeywords($propertyValue);
-
-                    break;
-                case 'initial-creator':
-                    $docProps->setCreator($propertyValue);
-                    $docProps->setLastModifiedBy($propertyValue);
-
-                    break;
-                case 'creation-date':
-                    $creationDate = strtotime($propertyValue);
-                    $creationDate = $creationDate === false ? time() : $creationDate;
-                    $docProps->setCreated($creationDate);
-                    $docProps->setModified($creationDate);
-
-                    break;
-                case 'user-defined':
-                    [, $attrName] = explode(':', $attributes['name']);
-                    switch ($attrName) {
-                        case 'publisher':
-                            $docProps->setCompany($propertyValue);
-
-                            break;
-                        case 'category':
-                            $docProps->setCategory($propertyValue);
+    private function userDefinedProperties(string $attrName, string $propertyValue): void
+    {
+        $docProps = $this->spreadsheet->getProperties();
+        switch ($attrName) {
+            case 'publisher':
+                $docProps->setCompany($propertyValue);
 
-                            break;
-                        case 'manager':
-                            $docProps->setManager($propertyValue);
+                break;
+            case 'category':
+                $docProps->setCategory($propertyValue);
 
-                            break;
-                    }
+                break;
+            case 'manager':
+                $docProps->setManager($propertyValue);
 
-                    break;
-            }
+                break;
         }
     }
 
-    public function readProperties(SimpleXMLElement $xml, SimpleXMLElement $gnmXML, array $namespacesMeta): void
+    public function readProperties(SimpleXMLElement $xml, SimpleXMLElement $gnmXML): void
     {
-        if (isset($namespacesMeta['office'])) {
-            $officeXML = $xml->children($namespacesMeta['office']);
+        $officeXML = $xml->children(Gnumeric::NAMESPACE_OFFICE);
+        if (!empty($officeXML)) {
             $officeDocXML = $officeXML->{'document-meta'};
             $officeDocMetaXML = $officeDocXML->meta;
 
             foreach ($officeDocMetaXML as $officePropertyData) {
-                $officePropertyDC = [];
-                if (isset($namespacesMeta['dc'])) {
-                    $officePropertyDC = $officePropertyData->children($namespacesMeta['dc']);
-                }
+                $officePropertyDC = $officePropertyData->children(Gnumeric::NAMESPACE_DC);
                 $this->docPropertiesDC($officePropertyDC);
 
-                $officePropertyMeta = [];
-                if (isset($namespacesMeta['meta'])) {
-                    $officePropertyMeta = $officePropertyData->children($namespacesMeta['meta']);
-                }
-                $this->docPropertiesMeta($officePropertyMeta, $namespacesMeta);
+                $officePropertyMeta = $officePropertyData->children(Gnumeric::NAMESPACE_META);
+                $this->docPropertiesMeta($officePropertyMeta);
             }
         } elseif (isset($gnmXML->Summary)) {
             $this->docPropertiesOld($gnmXML);
diff --git a/tests/PhpSpreadsheetTests/Reader/Gnumeric/GnumericLoadTest.php b/tests/PhpSpreadsheetTests/Reader/Gnumeric/GnumericLoadTest.php
index e24178e558..65511153b8 100644
--- a/tests/PhpSpreadsheetTests/Reader/Gnumeric/GnumericLoadTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Gnumeric/GnumericLoadTest.php
@@ -115,7 +115,12 @@ public function testLoad(): void
         self::assertEquals(Font::UNDERLINE_DOUBLE, $sheet->getCell('A24')->getStyle()->getFont()->getUnderline());
         self::assertTrue($sheet->getCell('B23')->getStyle()->getFont()->getSubScript());
         self::assertTrue($sheet->getCell('B24')->getStyle()->getFont()->getSuperScript());
-        self::assertFalse($sheet->getRowDimension(30)->getVisible());
+        $rowDimension = $sheet->getRowDimension(30);
+        if ($rowDimension === null) {
+            self::fail('Unable to get RowDimension for row 30)');
+        } else {
+            self::assertFalse($rowDimension->getVisible());
+        }
     }
 
     public function testLoadFilter(): void