In issue #4557, the user complains, with some justification, about the way Excel handles certain calculations. We are not able to help with that problem. However, the user also notes a problem in Shared/Date when `isDateTime` has to evaluate a cell whose calculated value is an array. This is solved by flattening the calculated result to a single value.
It became obvious while working on this change that the code to set `instanceArrayReturnType` was kind of awkward. Simpler methods `returnArrayAsArray` and `returnArrayAsValue` are added to `Spreadsheet`. Even these started out a bit awkward because `Spreadsheet::calculationEngine` was defined as nullable, which really isn't true. It is allocated by the constructor, and never freed except in the destructor. It is no longer nullable.
With PhpUnit 10 came the ability to use Php attributes rather than doc-block annotations for things like "data provider". PhpUnit 11 deprecates the use of annotations, and PhpUnit 12 will not not permit their use. Since PhpUnit 11 requires Php8.2+, we cannot adopt it as long as we support Php8.1, which will continue to be the case for some time. However, there is no penalty for early adoption.
Php-cs-fixer can use:
```
'php_unit_attributes' => ['keep_annotations' => false],
```
This allows us to run `composer fix` to automate all the needed changes. No manual changes were needed for any of the test members.
With this change, PhpUnit 9 can no longer be used with the test suite. File composer.json is updated to reflect that reality, and phpunit9.xml.dist, which has been supplied in case anyone needed to use PhpUnit 9, is no longer required, and is thus deleted. For now, PhpUnit 11 is not being added as a possibility.
No source code is changed in this PR.
* Eliminate Some Phpstan Annotations
Some changes are possible due to Php8+ features like null-safe operators and Stringable.
* Possible Uninitialized Variable
Scrutinizer might be technically correct.
* CellAddress Static -> Self
I don't understand the use case for extending it, which would be the reason for using static rather than self.
* Update Worksheet.php
While we might never be able to have 100% of our code strict, we can at
the very least do it for all of our tests. This ensures that our tests
are using our API with the types as intended by the test author, and not
silently be cast to what our API requires.
Successor to PR #3523. There are 494 single-line changes (`public function provider` to `public static function provider`) in this PR. None of these were made manually; they were all created with the following script (adapted from
https://stackoverflow.com/questions/25909820/how-to-recursively-iterate-through-files-in-php):
```php
$dir = 'C:/git/unit10prep2/tests/PhpSpreadsheetTests';
$it = new RecursiveDirectoryIterator($dir);
// Loop through files
foreach(new RecursiveIteratorIterator($it) as $file) {
if ($file->getExtension() === 'php') {
$contents = file_get_contents($file);
$new = preg_replace('/public function (\\w*)([Pp])rovider/', 'public static function $1$2rovider', $contents);
if ($new !== $contents) {
echo "changing $file\n";
file_put_contents($file, $new);
}
}
}
```
After this PR, there will be one more, with a small number of test changes, and enabling PhpUnit 10 for Php 8.1+.