Ensure that a basic metadata file containing a cell metadata definition is written and linked; and then tag array formula cells with the cm tag to link them to that cell metadata definition

src/PhpSpreadsheet/Cell/Cell.php

@@ -327,10 +327,10 @@ class Cell
                         //      as well as updating the spillage cells,
                         //  so we need to restore this cell to its formula value, attributes, and datatype
                         $worksheet->getCell($coordinate);
-                        $this->updateInCollection();
                         $this->value = $value;
                         $this->dataType = $datatype;
                         $this->formulaAttributes = $formulaAttributes;
+                        $this->updateInCollection();
                     }
 
                     // Now we just extract the top-left value from the array to get the result for this specific cell

src/PhpSpreadsheet/Writer/Xlsx.php

@@ -20,6 +20,7 @@ use PhpOffice\PhpSpreadsheet\Writer\Xlsx\Comments;
 use PhpOffice\PhpSpreadsheet\Writer\Xlsx\ContentTypes;
 use PhpOffice\PhpSpreadsheet\Writer\Xlsx\DocProps;
 use PhpOffice\PhpSpreadsheet\Writer\Xlsx\Drawing;
+use PhpOffice\PhpSpreadsheet\Writer\Xlsx\Metadata;
 use PhpOffice\PhpSpreadsheet\Writer\Xlsx\Rels;
 use PhpOffice\PhpSpreadsheet\Writer\Xlsx\RelsRibbon;
 use PhpOffice\PhpSpreadsheet\Writer\Xlsx\RelsVBA;
@@ -157,6 +158,11 @@ class Xlsx extends BaseWriter
      */
     private $writerPartStringTable;
 
+    /**
+     * @var Metadata
+     */
+    private $writerPartMetadata;
+
     /**
      * @var Style
      */
@@ -193,6 +199,7 @@ class Xlsx extends BaseWriter
         $this->writerPartRels = new Rels($this);
         $this->writerPartRelsRibbon = new RelsRibbon($this);
         $this->writerPartRelsVBA = new RelsVBA($this);
+        $this->writerPartMetadata = new Metadata($this);
         $this->writerPartStringTable = new StringTable($this);
         $this->writerPartStyle = new Style($this);
         $this->writerPartTheme = new Theme($this);
@@ -256,6 +263,11 @@ class Xlsx extends BaseWriter
         return $this->writerPartRelsVBA;
     }
 
+    public function getWriterPartMetadata(): Metadata
+    {
+        return $this->writerPartMetadata;
+    }
+
     public function getWriterPartStringTable(): StringTable
     {
         return $this->writerPartStringTable;
@@ -364,6 +376,9 @@ class Xlsx extends BaseWriter
         // Add theme to ZIP file
         $zipContent['xl/theme/theme1.xml'] = $this->getWriterPartTheme()->writeTheme($this->spreadSheet);
 
+        // Add metadata to ZIP file
+        $zipContent['xl/metadata.xml'] = $this->getWriterPartMetadata()->writeMetadata();
+
         // Add string table to ZIP file
         $zipContent['xl/sharedStrings.xml'] = $this->getWriterPartStringTable()->writeStringTable($this->stringTable);
 

src/PhpSpreadsheet/Writer/Xlsx/ContentTypes.php

@@ -82,6 +82,9 @@ class ContentTypes extends WriterPart
             $this->writeOverrideContentType($objWriter, '/xl/worksheets/sheet' . ($i + 1) . '.xml', 'application/vnd.openxmlformats-officedocument.spreadsheetml.worksheet+xml');
         }
 
+        // Shared strings
+        $this->writeOverrideContentType($objWriter, '/xl/metadata.xml', 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheetMetadata+xml');
+
         // Shared strings
         $this->writeOverrideContentType($objWriter, '/xl/sharedStrings.xml', 'application/vnd.openxmlformats-officedocument.spreadsheetml.sharedStrings+xml');
 

src/PhpSpreadsheet/Writer/Xlsx/Metadata.php

@@ -0,0 +1,181 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Writer\Xlsx;
+
+use PhpOffice\PhpSpreadsheet\Shared\XMLWriter;
+
+class Metadata extends WriterPart
+{
+    protected const METADATA_TYPES = [
+        [
+            'cellMeta' => '1',
+            'coerce' => '1',
+            'assign' => '1',
+            'clearComments' => '1',
+            'clearFormats' => '1',
+            'rowColShift' => '1',
+            'splitFirst' => '1',
+            'merge' => '1',
+            'pasteValues' => '1',
+            'pasteAll' => '1',
+            'copy' => '1',
+            'minSupportedVersion' => '120000',
+            'name' => 'XLDAPR',
+        ],
+        [
+            'coerce' => '1',
+            'assign' => '1',
+            'clearComments' => '1',
+            'clearFormats' => '1',
+            'rowColShift' => '1',
+            'splitFirst' => '1',
+            'merge' => '1',
+            'pasteValues' => '1',
+            'pasteAll' => '1',
+            'copy' => '1',
+            'minSupportedVersion' => '120000',
+            'name' => 'XLRICHVALUE',
+        ],
+    ];
+
+    protected const FUTURE_METADATA = [
+        'XLDAPR' => [
+            [
+                'uri' => '{bdbb8cdc-fa1e-496e-a857-3c3f30c029c3}',
+                'xda:dynamicArrayProperties' => [
+                    'fCollapsed' => '0',
+                    'fDynamic' => '1',
+                ],
+            ],
+        ],
+        'XLRICHVALUE' => [
+            [
+                'uri' => '{3e2802c4-a4d2-4d8b-9148-e3be6c30e623}',
+                'xlrd:rvb' => [
+                    'i' => '0',
+                ],
+            ],
+        ],
+    ];
+
+    protected const EXTRA_METADATA = [
+        'cellMetadata' => [
+            [
+                'v' => '0',
+                't' => '1',
+            ],
+        ],
+        'valueMetadata' => [
+            [
+                'v' => '0',
+                't' => '2',
+            ],
+        ],
+    ];
+
+    /**
+     * Write metadata to XML format.
+     *
+     * @return string XML Output
+     */
+    public function writeMetadata()
+    {
+        // Create XML writer
+        $objWriter = null;
+        if ($this->getParentWriter()->getUseDiskCaching()) {
+            $objWriter = new XMLWriter(XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
+        } else {
+            $objWriter = new XMLWriter(XMLWriter::STORAGE_MEMORY);
+        }
+
+        // XML header
+        $objWriter->startDocument('1.0', 'UTF-8', 'yes');
+
+        $objWriter->startElement('metadata');
+        $objWriter->writeAttribute('xmlns:xda', 'http://schemas.microsoft.com/office/spreadsheetml/2017/dynamicarray');
+        $objWriter->writeAttribute('xmlns:xlrd', 'http://schemas.microsoft.com/office/spreadsheetml/2017/richdata');
+        $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/spreadsheetml/2006/main');
+
+        $this->writeMetadataTypes($objWriter);
+        $this->writeFutureMetadata($objWriter);
+        $this->writeExtraMetadata($objWriter);
+
+        $objWriter->endElement(); // metadata
+
+        return $objWriter->getData();
+    }
+
+    private function writeMetadataTypes(XMLWriter $objWriter): void
+    {
+        $objWriter->startElement('metadataTypes');
+        $objWriter->writeAttribute('count', (string) count(self::METADATA_TYPES));
+
+        foreach (self::METADATA_TYPES as $metadataType) {
+            $objWriter->startElement('metadataType');
+
+            foreach ($metadataType as $metadataTypeKey => $metadataTypeValue) {
+                $objWriter->writeAttribute($metadataTypeKey, $metadataTypeValue);
+            }
+
+            $objWriter->endElement(); //metadataType
+        }
+
+        $objWriter->endElement(); //metadataTypes
+    }
+
+    private function writeFutureMetadata(XMLWriter $objWriter): void
+    {
+        foreach (self::FUTURE_METADATA as $name => $futureMetadata) {
+            $objWriter->startElement('futureMetadata');
+            $objWriter->writeAttribute('count', (string) count($futureMetadata));
+            $objWriter->writeAttribute('name', $name);
+
+            foreach ($futureMetadata as $futureMetadatum) {
+                $objWriter->startElement('bk');
+                $objWriter->startElement('extLst');
+
+                $ext = array_shift($futureMetadatum);
+                $objWriter->startElement('ext');
+                $objWriter->writeAttribute('uri', $ext);
+
+                foreach ($futureMetadatum as $extElementName => $extElementProperties) {
+                    $objWriter->startElement($extElementName);
+
+                    foreach ($extElementProperties as $extElementPropertyName => $extElementPropertyValue) {
+                        $objWriter->writeAttribute($extElementPropertyName, $extElementPropertyValue);
+                    }
+
+                    $objWriter->endElement(); // ext
+                }
+
+                $objWriter->endElement(); // ext
+                $objWriter->endElement(); // extLst
+                $objWriter->endElement(); // bk
+            }
+
+            $objWriter->endElement(); // futureMetadata
+        }
+    }
+
+    private function writeExtraMetadata(XMLWriter $objWriter): void
+    {
+        foreach (self::EXTRA_METADATA as $name => $metadata) {
+            $objWriter->startElement($name);
+            $objWriter->writeAttribute('count', (string) count($metadata));
+
+            foreach ($metadata as $metadatum) {
+                $objWriter->startElement('bk');
+                $objWriter->startElement('rc');
+
+                foreach ($metadatum as $attributeName => $attrbuteValue) {
+                    $objWriter->writeAttribute($attributeName, $attrbuteValue);
+                }
+
+                $objWriter->endElement(); // rc
+                $objWriter->endElement(); // bk
+            }
+
+            $objWriter->endElement();
+        }
+    }
+}

src/PhpSpreadsheet/Writer/Xlsx/Rels.php

@@ -137,6 +137,17 @@ class Rels extends WriterPart
                 'worksheets/sheet' . ($i + 1) . '.xml'
             );
         }
+
+        // Relationship sharedStrings.xml
+        // id : just after the last sheet
+        $this->writeRelationship(
+            $objWriter,
+            ($i + 1 + 3),
+            'http://schemas.openxmlformats.org/officeDocument/2006/relationships/sheetMetadata',
+            'metadata.xml'
+        );
+        ++$i; //increment i if needed for an another relation
+
         // Relationships for vbaProject if needed
         // id : just after the last sheet
         if ($spreadsheet->hasMacros()) {

src/PhpSpreadsheet/Writer/Xlsx/Worksheet.php

@@ -1265,11 +1265,13 @@ class Worksheet extends WriterPart
 
         $attributes = $cell->getFormulaAttributes();
         if (($attributes['t'] ?? null) === 'array') {
+            $objWriter->writeAttribute('cm', '1');
+
             $objWriter->startElement('f');
             $objWriter->writeAttribute('t', 'array');
             $objWriter->writeAttribute('ref', $attributes['ref'] ?? $cell->getCoordinate());
-            $objWriter->writeAttribute('aca', '1');
-            $objWriter->writeAttribute('ca', '1');
+            $objWriter->writeAttribute('aca', '1');     // Always calculate array, true
+            $objWriter->writeAttribute('ca', '1');      // Calculate cell, true
             $objWriter->text(Xlfn::addXlfnStripEquals($cellValue));
             $objWriter->endElement();
         } else {