[5.2] fix(export): type numeric answers as numbers in exports

Signed-off-by: Git'Fellow <12234510+solracsf@users.noreply.github.com>

Author: solracsf

lib/Service/SubmissionService.php

@@ -35,6 +35,7 @@
 use OCP\IUserSession;
 use OCP\Mail\IMailer;
 
+use PhpOffice\PhpSpreadsheet\Cell\DataType;
 use PhpOffice\PhpSpreadsheet\IOFactory;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
 use PhpOffice\PhpSpreadsheet\Writer\Csv;
@@ -348,17 +349,23 @@ private function exportData(array $header, array $data, string $fileFormat, ?Fil
 					$activeWorksheet->getStyle([$column, $row])
 						->getAlignment()
 						->setWrapText(true);
+				} elseif (!is_string($value)) {
+					$activeWorksheet->setCellValue([$column, $row], $value);
+				} elseif ($fileFormat === 'csv') {
+					// CSV is escaped (not typed) to neutralise formula-triggering values when opened in a spreadsheet app.
+					$activeWorksheet->getCell([$column, $row])
+						->setValueExplicit($this->escapeCSV($value), DataType::TYPE_STRING);
+				} elseif (is_numeric($value)
+					&& !in_array($value[0], ['=', '+', '-', '@'], true)
+					&& (string)(+$value) === $value) {
+					// Store numeric-looking answers (e.g. Radio labels "1"-"5") as numbers so they can be
+					// aggregated. The round-trip check keeps values whose canonical numeric form would differ
+					// (leading-zero phone numbers, "1e5", oversized ids, ...) as text.
+					$activeWorksheet->setCellValue([$column, $row], +$value);
 				} else {
-					// Explicitly set the type of the value to string for values that start with '=' to prevent it being interpreted as formulas
-					if (is_string($value)) {
-						$activeWorksheet->getCell([$column, $row])
-							->setValueExplicit($fileFormat === 'csv'
-								? $this->escapeCSV($value)
-								: $value,
-							);
-					} else {
-						$activeWorksheet->setCellValue([$column, $row], $value);
-					}
+					// Explicitly type as string so values that start with '=' are not interpreted as formulas.
+					$activeWorksheet->getCell([$column, $row])
+						->setValueExplicit($value, DataType::TYPE_STRING);
 				}
 			}
 		}