String Increments and Php8.5

Fix #4600. String incrementation through the `++` operator is deprecated in Php 8.5. Because we make use of that operator to iterate through columns, we are particularly hard hit by that change - unaddressed, it causes over 2,000 errors in our test suite! It is, fortunately, not as difficult as I feared to correct. Replacing the `++` operator with a call to new method `StringHelper::stringIncrement` in 79 statements scattered over 31 source modules (in src, samples, test, and infra) eliminates all the messages in the test suite. It is possible that others are lurking, but I don't know a systematic way of determining if there are others. We'll stick with this for now, and deal with any others as they show up.

This PR will be applied to the master, release390, and release222 branches. It will not be applied to the release210 or release1291 branches, which will now accept security changes only.

Author: oleibman

CONTRIBUTING.md

@@ -43,7 +43,7 @@ This makes it easier to see exactly what is being tested when reviewing the PR.
 4. By default, Github removes markdown headings in the Release Notes. You can either edit to restore these, or, probably preferably, change the default comment character on your system - `git config core.commentChar ";"`.
 
 > **Note:** Tagged releases are made from the `master` branch. Only in an emergency should a tagged release be made from the `release` branch. (i.e. cherry-picked hot-fixes.) However, there are 4 branches which have been updated to apply security patches, and those may be tagged if future security updates are needed.
-- release1291
-- release210
+- release1291 (no further updates aside from security patches, including code changes needed for Php 8.5 compatibility)
+- release210 (no further updates aside from security patches, including code changes needed for Php 8.5 compatibility)
 - release222
 - release390

README.md

@@ -1,8 +1,7 @@
 # PhpSpreadsheet
 
 [![Build Status](https://github.com/PHPOffice/PhpSpreadsheet/workflows/main/badge.svg)](https://github.com/PHPOffice/PhpSpreadsheet/actions)
-[![Code Quality](https://scrutinizer-ci.com/g/PHPOffice/PhpSpreadsheet/badges/quality-score.png?b=master)](https://scrutinizer-ci.com/g/PHPOffice/PhpSpreadsheet/?branch=master)
-[![Code Coverage](https://scrutinizer-ci.com/g/PHPOffice/PhpSpreadsheet/badges/coverage.png?b=master)](https://scrutinizer-ci.com/g/PHPOffice/PhpSpreadsheet/?branch=master)
+[![Code Coverage](https://coveralls.io/repos/github/PHPOffice/PhpSpreadsheet/badge.svg?branch=master)](https://coveralls.io/github/PHPOffice/PhpSpreadsheet?branch=master)
 [![Total Downloads](https://img.shields.io/packagist/dt/PHPOffice/PhpSpreadsheet)](https://packagist.org/packages/phpoffice/phpspreadsheet)
 [![Latest Stable Version](https://img.shields.io/github/v/release/PHPOffice/PhpSpreadsheet)](https://packagist.org/packages/phpoffice/phpspreadsheet)
 [![License](https://img.shields.io/github/license/PHPOffice/PhpSpreadsheet)](https://packagist.org/packages/phpoffice/phpspreadsheet)
@@ -11,6 +10,17 @@
 PhpSpreadsheet is a library written in pure PHP and offers a set of classes that
 allow you to read and write various spreadsheet file formats such as Excel and LibreOffice Calc.
 
+This is the master branch, and is maintained for security and bug fixes.
+
+## PHP Version Support
+
+LTS: For maintained branches, support for PHP versions will only be maintained for a period of six months beyond the
+[end of life](https://www.php.net/supported-versions) of that PHP version.
+
+Currently the required PHP minimum version is PHP __8.1__, and we [will support that version](https://www.php.net/supported-versions.php) until 30th June 2026.
+
+See the `composer.json` for other requirements.
+
 ## Installation
 
 See the [install instructions](https://phpspreadsheet.readthedocs.io/en/latest/#installation).

docs/topics/accessing-cells.md

@@ -472,6 +472,7 @@ $highestColumnIndex = \PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFrom
 echo '<table>' . "\n";
 for ($row = 1; $row <= $highestRow; ++$row) {
     echo '<tr>' . PHP_EOL;
+    // Use StringHelper::stringIncrement($col) rather than ++$col if using Php8.5+.
     for ($col = 1; $col <= $highestColumnIndex; ++$col) {
         $value = $worksheet->getCell([$col, $row])->getValue();
         echo '<td>' . $value . '</td>' . PHP_EOL;
@@ -494,11 +495,12 @@ $worksheet = $spreadsheet->getActiveSheet();
 $highestRow = $worksheet->getHighestDataRow(); // e.g. 10
 $highestColumn = $worksheet->getHighestDataColumn(); // e.g 'F'
 // Increment the highest column letter
-++$highestColumn;
+++$highestColumn; // StringHelper::stringIncrement($highestColumn); if using Php8.5+.
 
 echo '<table>' . "\n";
 for ($row = 1; $row <= $highestRow; ++$row) {
     echo '<tr>' . PHP_EOL;
+    // Use StringHelper::stringIncrement($col) rather than ++$col if using Php8.5+.
     for ($col = 'A'; $col != $highestColumn; ++$col) {
         echo '<td>' .
              $worksheet->getCell($col . $row)

docs/topics/migration-from-PHPExcel.md

@@ -418,13 +418,15 @@ So the code must be adapted with something like:
 // Before
 $cell = $worksheet->getCellByColumnAndRow($column, $row);
 
+// Use StringHelper::stringIncrement($column) rather than ++$column if using Php8.5+.
 for ($column = 0; $column < $max; ++$column) {
     $worksheet->setCellValueByColumnAndRow($column, $row, 'value');
 }
 
 // After
 $cell = $worksheet->getCell([$column + 1, $row]);
 
+// Use StringHelper::stringIncrement($column) rather than ++$column if using Php8.5+.
 for ($column = 1; $column <= $max; ++$column) {
     $worksheet->setCellValue([$column, $row], 'value');
 }

infra/LocaleGenerator.php

@@ -5,6 +5,7 @@
 use Exception;
 use PhpOffice\PhpSpreadsheet\Cell\Cell;
 use PhpOffice\PhpSpreadsheet\IOFactory;
+use PhpOffice\PhpSpreadsheet\Shared\StringHelper;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
 use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;
 
@@ -283,7 +284,7 @@ protected function mapLanguageColumns(Worksheet $translationWorksheet): array
         $this->log("Mapping Languages for {$sheetName}:");
 
         $baseColumn = self::ENGLISH_REFERENCE_COLUMN;
-        $languagesList = $translationWorksheet->getColumnIterator(++$baseColumn);
+        $languagesList = $translationWorksheet->getColumnIterator(StringHelper::stringIncrement($baseColumn));
 
         $languageNameMap = [];
         foreach ($languagesList as $languageColumn) {

samples/Basic1/13_Calculation.php

@@ -1,6 +1,7 @@
 <?php
 
 use PhpOffice\PhpSpreadsheet\Calculation\Calculation;
+use PhpOffice\PhpSpreadsheet\Shared\StringHelper;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
 
 mt_srand(1234567890);
@@ -156,7 +157,7 @@
 
 // Calculated data
 $helper->log('Calculated data');
-for ($col = 'B'; $col != 'G'; ++$col) {
+for ($col = 'B'; $col != 'G'; StringHelper::stringIncrement($col)) {
     for ($row = 14; $row <= 41; ++$row) {
         $formula = $spreadsheet->getActiveSheet()->getCell($col . $row)->getValue();
         if (

samples/Basic1/13_CalculationCyclicFormulae.php

@@ -1,6 +1,7 @@
 <?php
 
 use PhpOffice\PhpSpreadsheet\Calculation\Calculation;
+use PhpOffice\PhpSpreadsheet\Shared\StringHelper;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
 
 require __DIR__ . '/../Header.php';
@@ -22,7 +23,7 @@
 // Calculated data
 $helper->log('Calculated data');
 for ($row = 1; $row <= 2; ++$row) {
-    for ($col = 'A'; $col != 'C'; ++$col) {
+    for ($col = 'A'; $col != 'C'; StringHelper::stringIncrement($col)) {
         $formula = $spreadsheet->getActiveSheet()->getCell($col . $row)->getValue();
         if (
             is_string($formula)

samples/Basic3/39_Dropdown.php

@@ -2,6 +2,7 @@
 
 use PhpOffice\PhpSpreadsheet\Cell\DataValidation;
 use PhpOffice\PhpSpreadsheet\NamedRange;
+use PhpOffice\PhpSpreadsheet\Shared\StringHelper;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
 
 require __DIR__ . '/../Header.php';
@@ -59,7 +60,7 @@ function transpose(string $value): array
     $spreadsheet->getActiveSheet()
         ->setCellValue($continentColumn . ($key + 1), $continent);
 
-    ++$column;
+    StringHelper::stringIncrement($column);
 }
 
 // Hide the dropdown data

samples/ConditionalFormatting/05_Date_Comparisons.php

@@ -1,5 +1,6 @@
 <?php
 
+use PhpOffice\PhpSpreadsheet\Shared\StringHelper;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
 use PhpOffice\PhpSpreadsheet\Style\Alignment;
 use PhpOffice\PhpSpreadsheet\Style\Color;
@@ -97,7 +98,7 @@
     ->fromArray($dateFunctionArray, null, 'B1', true);
 $spreadsheet->getActiveSheet()
     ->fromArray($dateTitleArray, null, 'A2', true);
-for ($column = 'B'; $column !== 'L'; ++$column) {
+for ($column = 'B'; $column !== 'L'; StringHelper::stringIncrement($column)) {
     $spreadsheet->getActiveSheet()
         ->fromArray($dataArray, null, "{$column}2", true);
 }
@@ -117,7 +118,7 @@
 
 // Set conditional formatting rules and styles
 $helper->log('Define conditional formatting and set styles');
-for ($column = 'B'; $column !== 'L'; ++$column) {
+for ($column = 'B'; $column !== 'L'; StringHelper::stringIncrement($column)) {
     $wizardFactory = new Wizard("{$column}2:{$column}19");
     /** @var Wizard\DateValue $dateWizard */
     $dateWizard = $wizardFactory->newRule(Wizard::DATES_OCCURRING);
@@ -141,7 +142,7 @@
 $helper->log('Set some additional styling for date formats');
 
 $spreadsheet->getActiveSheet()->getStyle('B:B')->getNumberFormat()->setFormatCode('ddd dd-mmm-yyyy');
-for ($column = 'A'; $column !== 'L'; ++$column) {
+for ($column = 'A'; $column !== 'L'; StringHelper::stringIncrement($column)) {
     if ($column !== 'A') {
         $spreadsheet->getActiveSheet()->getStyle("{$column}:{$column}")
             ->getNumberFormat()->setFormatCode('ddd dd-mmm-yyyy');

samples/LookupRef/VLOOKUP.php

@@ -1,5 +1,6 @@
 <?php
 
+use PhpOffice\PhpSpreadsheet\Shared\StringHelper;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
 
 require __DIR__ . '/../Header.php';
@@ -40,7 +41,7 @@
 $worksheet->getCell('I5')->setValue('=VLOOKUP(I3, B3:E9, 4, FALSE)');
 $worksheet->getCell('J5')->setValue('=VLOOKUP(J3, B3:E9, 4, FALSE)');
 
-for ($column = 'H'; $column !== 'K'; ++$column) {
+for ($column = 'H'; $column !== 'K'; StringHelper::stringIncrement($column)) {
     for ($row = 4; $row <= 5; ++$row) {
         $cell = $worksheet->getCell("{$column}{$row}");
         $helper->log("{$column}{$row}: " . $cell->getValueString() . ' => ' . $cell->getCalculatedValueString());