Fix deprecated $php_errormsg in PHP 7.2

[ziegenberg]

From the PHP 8.0 migration guide (https://www.php.net/manual/de/migration80.incompatible.php):

The track_errors ini directive has been removed.
This means that $php_errormsg is no longer available.
The error_get_last() function may be used instead.

Also the documentation on $php_errormsg (https://www.php.net/manual/en/reserved.variables.phperrormsg.php) says:

This feature has been DEPRECATED as of PHP 7.2.0.
Relying on this feature is highly discouraged.
Use error_get_last() instead.

The functions Horde_String::convertCharset and Horde_String::_pos are broken up to assist in better testability and additional tests for the newly introduced functions are added.

This commit breaks compatibility with PHP 5.6 as error_clear_last() was introduced with PHP 7.

[bytestream]

A test could be helpful - if possible - something that at least covers the code if not directly tests the issue raised here 👀

I don't recall this coming up when running the tests on PHP 8.0 or 8.1

[marinaglancy]

I don't think it's possible. All these changes are made to the if-blocks that check that some php extensions are not available (iconv/mbstring/intl). If you had testing environment without these extensions, many other tests would fail

[ziegenberg]

I guess, one could mock Horde_Util::extensionExists() like so:

$util = $this->getMockBuilder(Horde_Util::class)
    ->setMethods(array('extensionExists'))
    ->getMock();
$map = [
    ['xml', false],
    ['iconv', true],
    ['mbstring', false]
];
$util->expects($this->any())
    ->method('extensionExists')
    ->will($this->returnValueMap($map));

and then there still needs to be a test developed.

I'm currently challenged with installing the Horde Git Tools. The reason is: composer version 2 dropped pear support... 😐

[bytestream]

Yeah never mind; it looks like the function would need to be broken up to make it easier to test. Thanks for looking into it.

[yunosh]

This isn't anything we could apply until we finally drop PHP 5.6 support. Which is overdue, admittedly.

[ziegenberg]

People are preparing for PHP 8, starting to leave PHP 7 behind some them soon. Is there a roadmap for dropping support for PHP 5.6? Can you tell a date and time for the transition? Some might start looking for replacement frameworks :(

[yunosh]

Yes, we'll drop PHP 5 support with Horde 6.

[ziegenberg]

Is there an ETA for Horde 6?

[ziegenberg]

@bytestream I amended my pull request and broke up the two functions to make it easier to test and also added some basic tests.