* Csv Handling of Booleans (and an 8.1 Deprecation)
PhpSpreadsheet writes boolean values to a Csv as null-string/1, and treats input values of 'true' and 'false' as if they were strings. On the other hand, Excel writes boolean values to a Csv as TRUE/FALSE, and case-insensitively treats a matching string as boolean on read. This PR changes PhpSpreadsheet to match Excel.
A side-effect of this change is that it fixes behavior incorrectly reported as a bug in PR #2048. That issue was closed, correctly, as user error. The user had altered Csv Writer, including adding ```declare(strict_types=1);```; that declaration was the cause of the error. The "offending" statements, calls to strpbrk and str_replace, will now work correctly whether or not strict_types is in use.
And, just as I was getting ready to push this, the dailies for PHP 8.1 introduced a change deprecating auto_detect_line_endings. Csv Reader uses that setting; it allows it to process a Csv with Mac line endings, which happens to be something that Excel can do. As they say in https://wiki.php.net/rfc/deprecations_php_8_1, where the proposal passed without a single dissenting vote, "These newlines were used by “Classic” Mac OS, a system which has been discontinued in 2001, nearly two decades ago. Interoperability with such systems is no longer relevant." I tend to agree, but I don't know that we're ready to pull the plug yet. I don't see an easy way to emulate that functionality. For now, I have silenced the deprecation notices with at signs. I have also added a test case which will fail when support for that setting is pulled; this will give time to consider alternatives.
* Scrutinizer: Handling ini_set
This could be interesting. It doesn't like not handling an error condition for ini_set. Let's see if this satisfies it.
* Fix For #1509
User expected no CSV enclosures after $writer->setEnclosure(''),
which had been changed to be consistent with $reader->setEnclosure('').
Writer will now omit enclosures after code above; no change to Reader.
Tests have been added for this condition.
* Add Option to Write CSV Enclosure Only When Required
Allowing the user to specify no enclosure when writing a CSV can lead to
a situation where PhpSpreadsheet (likewise Excel) will not read the
resulting file as intended, e.g. if any cell contains a delimiter character.
This is demonstrated in new test TestBadReread.
No existing setting will rectify this situation.
A better choice would be to add an option to write the enclosure
only when it is needed, which is what Excel does. The RFC4180 spec at
https://tools.ietf.org/html/rfc4180
states when it is needed - when the cell contains the delimiter,
or the enclosure, or a newline.
New test TestGoodReread demonstrates that the file is read as intended.
The documentation has been updated to describe the new function,
and to change the write example where the enclosure is set to null.
* Scrutinizer Suggestions
3 minor changes, all in tests.