… path and a custom iterator (fxbt)This PR was submitted for the 2.8 branch but it was squashed and merged into the 4.2-dev branch instead (closes#26771).Discussion----------[Filesystem] Fix mirroring a directory with a relative path and a custom iterator| Q             | A| ------------- | ---| Branch?       | 2.8 up to 4.1| Bug fix?      | yes| New feature?  | no| BC breaks?    | no| Deprecations? | no| Tests pass?   | yes| Fixed tickets || License       | MIT| Doc PR        |The Filesystem::mirror method with a Finder iterator doesn't work if the origin directory is relative.This is a case where it won't work:```$dir = '/data/../data/';$finder = (new Finder())->in($dir)->getIterator();(new Filesystem())->mirror($dir, '/tmp', $finder);```The finder will return file objects like this :```SplFileInfo {    pathname: "/data/file.tmp"    ...}```But the following line will fail because because the `$file->getPathname()` and the `$originDir` are differents.```$target = $targetDir.substr($file->getPathname(), $originDirLen);// $file->getPathname() = '/data/file.tmp'// $originDirLen = strlen('/data/../data/') = 14// $target = '/tmp' instead of '/tpm/file.tpm'```In some case, it's even worse. If the filename length is bigger than the `$originDirLen`, the target file will be a file with a completely wrong name:```// $file->getPathname() = '/data/file123456789.tmp'// $originDirLen = strlen('/data/../data/') = 14// $target = '/tmp/56789.tmp' instead of '/tpm/file123456789.tmp'```I fixed this on my side by using the realpath function everytime i'm calling the mirror method, but i doubt this is the desired behavior.Commits-------27b673c [Filesystem] Fix mirroring a directory with a relative path and a custom iterator