Merge pull request #3352 from PHPOffice/PR3329-Additional-Exception-Handling

Additional exception handling to prevent an invalid formula from breaking `isDateTime()`

src/PhpSpreadsheet/Shared/Date.php

@@ -375,13 +375,18 @@ class Date
         if ($worksheet !== null && $spreadsheet !== null) {
             $index = $spreadsheet->getActiveSheetIndex();
             $selected = $worksheet->getSelectedCells();
-            $result = is_numeric($value ?? $cell->getCalculatedValue()) &&
-                self::isDateTimeFormat(
-                    $worksheet->getStyle(
-                        $cell->getCoordinate()
-                    )->getNumberFormat(),
-                    $dateWithoutTimeOkay
-                );
+
+            try {
+                $result = is_numeric($value ?? $cell->getCalculatedValue()) &&
+                    self::isDateTimeFormat(
+                        $worksheet->getStyle(
+                            $cell->getCoordinate()
+                        )->getNumberFormat(),
+                        $dateWithoutTimeOkay
+                    );
+            } catch (Exception $e) {
+                // Result is already false, so no need to actually do anything here
+            }
             $worksheet->setSelectedCells($selected);
             $spreadsheet->setActiveSheetIndex($index);
         }

tests/PhpSpreadsheetTests/Shared/DateTest.php

@@ -262,5 +262,14 @@ class DateTest extends TestCase
             ->getNumberFormat()
             ->setFormatCode('0.00E+00');
         self::assertFalse(null !== $cella3 && Date::isDateTime($cella3));
+
+        $cella4 = $sheet->getCell('A4');
+        self::assertNotNull($cella4);
+
+        $cella4->setValue('= 44 7510557347');
+        $sheet->getStyle('A4')
+            ->getNumberFormat()
+            ->setFormatCode('yyyy-mm-dd');
+        self::assertFalse(Date::isDateTime($cella4));
     }
 }