Unexpected Exception in Php DateTime

Fix #4696. Fix #917 (which had gone stale but is now reopened). Fix #916. People were receiving unexpected exceptions calling `Date::isDateTime($cell)`. 916 and 917 had been mostly resolved long ago by adding a numeric check on the contents of $cell. However, it turns out that the use of values with very large absolute values can cause Php DateTime to throw an exception, which is the problem with 4696, when it calls `Date::toExcelDateTimeObject` for a cell with a large integer value.

`Date::toExcelDateTimeObject` is coded to return a Php DateTime object. I don't see any reasonable non-breaking fix for that. People can always add try/catch if they are worried about that. However, `Date::isDateTime` can add an additional check and return `false` if this situation occurs. All 3 of the issues resolved by this PR mention isDateTime in their discussion; they are all fixed without additional coding changes by this.

An additional change is needed for `Cell::getFormattedValue` to avoid this problem. This is fixed in `Style::NumberFormatter::DateFormatter::format`.

src/PhpSpreadsheet/Shared/Date.php

@@ -11,6 +11,7 @@ use PhpOffice\PhpSpreadsheet\Cell\Cell;
 use PhpOffice\PhpSpreadsheet\Exception;
 use PhpOffice\PhpSpreadsheet\Exception as PhpSpreadsheetException;
 use PhpOffice\PhpSpreadsheet\Style\NumberFormat;
+use Throwable;
 
 class Date
 {
@@ -376,15 +377,18 @@ class Date
                         $cell->getCalculatedValue()
                     );
                 }
-                $result = is_numeric($value)
-                    && self::isDateTimeFormat(
+                if (is_numeric($value)) {
+                    $result = self::isDateTimeFormat(
                         $worksheet->getStyle(
                             $cell->getCoordinate()
                         )->getNumberFormat(),
                         $dateWithoutTimeOkay
                     );
-            } catch (Exception) {
-                // Result is already false, so no need to actually do anything here
+                    /** @var float|int $value */
+                    self::excelToDateTimeObject($value);
+                }
+            } catch (Throwable) {
+                $result = false;
             }
             $worksheet->setSelectedCells($selected);
             $spreadsheet->setActiveSheetIndex($index);

src/PhpSpreadsheet/Style/NumberFormat/DateFormatter.php

@@ -3,6 +3,8 @@
 namespace PhpOffice\PhpSpreadsheet\Style\NumberFormat;
 
 use PhpOffice\PhpSpreadsheet\Shared\Date;
+use PhpOffice\PhpSpreadsheet\Shared\StringHelper;
+use Throwable;
 
 class DateFormatter
 {
@@ -161,7 +163,11 @@ class DateFormatter
         $callback = [self::class, 'escapeQuotesCallback'];
         $format = (string) preg_replace_callback('/"(.*)"/U', $callback, $format);
 
-        $dateObj = Date::excelToDateTimeObject($value);
+        try {
+            $dateObj = Date::excelToDateTimeObject($value);
+        } catch (Throwable) {
+            return StringHelper::convertToString($value);
+        }
         // If the colon preceding minute had been quoted, as happens in
         // Excel 2003 XML formats, m will not have been changed to i above.
         // Change it now.

tests/PhpSpreadsheetTests/Shared/Issue4696Test.php

@@ -0,0 +1,62 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpOffice\PhpSpreadsheetTests\Shared;
+
+use PhpOffice\PhpSpreadsheet\Cell\DataType;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+
+class Issue4696Test extends TestCase
+{
+    private ?Spreadsheet $spreadsheet = null;
+
+    protected function tearDown(): void
+    {
+        if ($this->spreadsheet !== null) {
+            $this->spreadsheet->disconnectWorksheets();
+            $this->spreadsheet = null;
+        }
+    }
+
+    #[DataProvider('providerIsDateTime')]
+    public function testTimeOnly(bool $expectedResult, string $expectedFormatted, int|float|string $value): void
+    {
+        $this->spreadsheet = new Spreadsheet();
+        $sheet = $this->spreadsheet->getActiveSheet();
+        if (is_string($value) && $value[0] !== '=') {
+            $sheet->getCell('A1')->setValueExplicit($value, DataType::TYPE_STRING);
+        } else {
+            $sheet->getCell('A1')->setValue($value);
+        }
+        $sheet->getStyle('A1')->getNumberFormat()
+            ->setFormatCode('yyyy-mm-dd');
+        self::assertSame(
+            $expectedResult,
+            Date::isDateTime($sheet->getCell('A1'))
+        );
+        self::assertSame(
+            $expectedFormatted,
+            $sheet->getCell('A1')->getFormattedValue()
+        );
+    }
+
+    public static function providerIsDateTime(): array
+    {
+        return [
+            'valid integer' => [true, '1903-12-31', 1461],
+            'valid integer stored as string' => [true, '1904-01-01', '1462'],
+            'valid integer stored as concatenated string' => [true, '1904-01-01', '="14"&"62"'],
+            'valid float' => [true, '1903-12-31', 1461.5],
+            'valid float stored as string' => [true, '1903-12-31', '1461.5'],
+            'out-of-range integer' => [false, '7000989091802000122', 7000989091802000122],
+            'out-of-range float' => [false, '7.000989091802E+18', 7000989091802000122.1],
+            'out-of-range float stored as string' => [false, '7000989091802000122.1', '7000989091802000122.1'],
+            'non-numeric' => [false, 'xyz', 'xyz'],
+            'issue 917' => [false, '5e8630b8-603c-43fe-b038-6154a3f893ab', '5e8630b8-603c-43fe-b038-6154a3f893ab'],
+        ];
+    }
+}