Excel Inconsistent Handling of Empty Argument MIN/MAX/MINA/MAXA

Fix #3866. Excel normally treats a missing argument (e.g. `PRODUCT(2,3,)`) as null and ignores it. Not so for MIN/MAX/MINA/MAXA; for those, an empty argument is treated as zero. PhpSpreadsheet is changed to do the same.

docs/topics/recipes.md

@@ -415,6 +415,7 @@ At present, the following locale settings are supported:
 
 Language             |                      | Locale Code
 ---------------------|----------------------|-------------
+Bulgarian            | български            | bg
 Czech                | Ceština              | cs
 Danish               | Dansk                | da
 German               | Deutsch              | de

src/PhpSpreadsheet/Calculation/Calculation.php

@@ -4997,7 +4997,12 @@ private function processTokenStack(mixed $tokens, ?string $cellID = null, ?Cell
                             }
                         } else {
                             $emptyArguments[] = ($arg['type'] === 'Empty Argument');
-                            $args[] = self::unwrapResult($arg['value']);
+                            if ($arg['type'] === 'Empty Argument' && in_array($functionName, ['MIN', 'MINA', 'MAX', 'MAXA'], true)) {
+                                $args[] = $arg['value'] = 0;
+                                $this->debugLog->writeDebugLog('Empty Argument reevaluated as 0');
+                            } else {
+                                $args[] = self::unwrapResult($arg['value']);
+                            }
                             if ($functionName !== 'MKMATRIX') {
                                 $argArrayVals[] = $this->showValue($arg['value']);
                             }

tests/PhpSpreadsheetTests/Calculation/MissingArgumentsTest.php

@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation;
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+use PHPUnit\Framework\TestCase;
+
+class MissingArgumentsTest extends TestCase
+{
+    /**
+     * @dataProvider providerMissingArguments
+     */
+    public function testMissingArguments(mixed $expected, string $formula): void
+    {
+        $spreadsheet = new Spreadsheet();
+        $sheet = $spreadsheet->getActiveSheet();
+        $sheet->getCell('A1')->setValue($formula);
+        self::assertSame($expected, $sheet->getCell('A1')->getCalculatedValue());
+        $spreadsheet->disconnectWorksheets();
+    }
+
+    public static function providerMissingArguments(): array
+    {
+        return [
+            'argument missing at end' => [0, '=min(3,2,)'],
+            'argument missing at beginning' => [0, '=mina(,3,2)'],
+            'argument missing in middle' => [0, '=min(,3,2)'],
+            'missing argument is not result' => [-2, '=min(3,-2,)'],
+            'max with missing argument' => [0, '=max(-3,-2,)'],
+            'maxa with missing argument' => [0, '=maxa(-3,-2,)'],
+            'max with null cell' => [-2, '=max(-3,-2,Z1)'],
+            'min with null cell' => [2, '=min(3,2,Z1)'],
+            'product ignores null argument' => [6.0, '=product(3,2,)'],
+            'embedded function' => [5, '=sum(3,2,min(3,2,))'],
+            'unaffected embedded function' => [8, '=sum(3,2,max(3,2,))'],
+        ];
+    }
+}