Excel Omits Between Operator for Data Validation

Fix #3863. Data Validation default operator is `between`. When Excel writes out a data validation item, it may omit the operator. Xlsx reader will therefore initialize operator to null string. Issue indicates that user wants `between` returned for `getOperator`. A more serious problem is that `isValid` method does not handle this situation correctly. Data Validation is changed to set Operator to the default value if an attempt is made to set it to null string.

src/PhpSpreadsheet/Cell/DataValidation.php

@@ -28,6 +28,7 @@ class DataValidation
     const OPERATOR_LESSTHANOREQUAL = 'lessThanOrEqual';
     const OPERATOR_NOTBETWEEN = 'notBetween';
     const OPERATOR_NOTEQUAL = 'notEqual';
+    private const DEFAULT_OPERATOR = self::OPERATOR_BETWEEN;
 
     /**
      * Formula 1.
@@ -52,7 +53,7 @@ class DataValidation
     /**
      * Operator.
      */
-    private string $operator = self::OPERATOR_BETWEEN;
+    private string $operator = self::DEFAULT_OPERATOR;
 
     /**
      * Allow Blank.
@@ -198,7 +199,7 @@ class DataValidation
      */
     public function setOperator(string $operator): static
     {
-        $this->operator = $operator;
+        $this->operator = ($operator === '') ? self::DEFAULT_OPERATOR : $operator;
 
         return $this;
     }

tests/PhpSpreadsheetTests/Reader/Xlsx/Issue3863Test.php

@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpOffice\PhpSpreadsheetTests\Reader\Xlsx;
+
+use PhpOffice\PhpSpreadsheet\Cell\DataValidator;
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx;
+
+class Issue3863Test extends \PHPUnit\Framework\TestCase
+{
+    private static string $testbook = 'tests/data/Reader/XLSX/issue.3863.xlsx';
+
+    public function testPreliminaries(): void
+    {
+        $file = 'zip://';
+        $file .= self::$testbook;
+        $file .= '#xl/worksheets/sheet1.xml';
+        $data = file_get_contents($file);
+        if ($data === false) {
+            self::fail('Unable to read file');
+        } else {
+            // Only 1 Data Validation and it does not specify operator
+            self::assertStringContainsString('<dataValidations count="1"><dataValidation type="whole" allowBlank="1" showInputMessage="1" showErrorMessage="1" sqref="A1" xr:uid="{D0F98CC5-7234-4ADF-BD42-F33321DCD3CA}"><formula1>5</formula1><formula2>10</formula2></dataValidation></dataValidations>', $data);
+        }
+    }
+
+    public function testValidData(): void
+    {
+        $reader = new Xlsx();
+        $spreadsheet = $reader->load(self::$testbook);
+        $sheet = $spreadsheet->getActiveSheet();
+        self::assertSame('between', $sheet->getCell('A1')->getDataValidation()->getOperator());
+        $validator = new DataValidator();
+        self::assertTrue($validator->isValid($sheet->getCell('A1')));
+        $sheet->getCell('A1')->setValue(3);
+        self::assertFalse($validator->isValid($sheet->getCell('A1')));
+        $sheet->getCell('A1')->setValue(7);
+        self::assertTrue($validator->isValid($sheet->getCell('A1')));
+        $spreadsheet->disconnectWorksheets();
+    }
+}