[Bug] 77024 - Correct the behaviour of casting spl files to strings

[duncan3dc]

Bug #77024

This PR makes __toString() in a CSV context consistent with a plain text file.

This behaviour contradicts the manual (and common sense as far as I can tell) but this PR ensures backwards compatibility

[nikic]

The test currently fails on Windows. It's probably best not to use a temporary file. Either use SplTempFileObject for the second part as well, or create an actual file for this.

[duncan3dc]

@nikic The second test is to ensure SplFileObject works too, if we use SplTempFileObject again then we have no regression test that protects us from somebody changing the behaviour of SplFileObject do we?
Looking at the AppVeyor error, presumably adding an unset($file) before unlink() may resolve it?

[nikic]

Looking at the AppVeyor error, presumably adding an unset($file) before unlink() may resolve it?

If that works, that would be fine as well.

[petk]

Or add the unlink() call into the --CLEAN-- section instead. I think that helps on Windows in some cases also.

[duncan3dc]

Windows build is fixed now 👍

[petk]

Applied via 91c6fb8 to PHP-7.2+. Thank you @duncan3dc and the reviewers...