id	summary	reporter	owner	description	type	status	priority	milestone	component	version	severity	resolution	keywords	cc
22267	Make trailingslashit() and untrailingslashit() work with backslashes	knutsp		"#20778 demonstrates that untrailinhslashit(), hence trailingslashit(), are unable to remove a trailing backslash from file paths on Windows.

As Windows accepts a slash as directory separator, DIRECTORY_SEPARATOR is not needed to make portable code, except when parsing or exploding a path that comes from the system [http://alanhogan.com/tips/php/directory-separator-not-necessary]. We neeed to tell trailingslashit() and untrailingslashit() that we want to remove the trailing slash a file path from system, not a generated one and not a URL path.

My idea is:
{{{
function untrailingslashit( $string, $is_path = false ) {
    if ( $is_path )
        return rtrim( $string, DIRECTORY_SEPARATOR . '/' );
    else
        return rtrim( $string, '/');
}

function trailingslashit( $string, $is_path = false ) {
    if ( $is_path )
        return untrailingslashit( $string, $is_path ) . DIRECTORY_SEPARATOR;
    else
        return untrailingslashit( $string ) . '/';
}
}}}

Expected results that is true:

{{{
  trailingslashit( '/mypath'  ) == '/mypath/'
  trailingslashit( '/mypath/' ) == '/mypath/'
  trailingslashit( '/mypath//') == '/mypath/'
untrailingslashit( '/mypath/' ) == '/mypath'
untrailingslashit( '/mypath//') == '/mypath'
  trailingslashit( '/usr/tmp/', true ) == '/usr/tmp/' // On non-Windows
  trailingslashit( '/usr/tmp',  true ) == '/usr/tmp/' // On non-Windows
  trailingslashit( '/usr/tmp//',true ) == '/usr/tmp/' // On non-Windows
  trailingslashit( 'C:\TEMP',   true ) == 'C:\TEMP\'  // On Windows
  trailingslashit( 'C://TEMP//',true ) == 'C://TEMP\' // On Windows
  trailingslashit( 'C:/TEMP/',  true ) == 'C:/TEMP\'  // On Windows
untrailingslashit( 'C:\TEMP\',  true ) == 'C:\TEMP'   // On Windows
}}}

On Windows, for making a path to $subdir one may use either

{{{
$path = trailingslashit( $path, true ) . $subdir;
$path = untrailingslashit( $path, true ) . '/' . $subdir;
}}}
according to preference in the situation, knowing that '/' is a valid separator in any case.

The added DIRECTORY_SEPARATOR in trailingslashit() code suggestion above could be '/', but it might produce an unexpected result, some someone when deliberately wants to make a true native path for the system.

The second parameter to rtrim() in untrailingslashit() should instruct rtrim() to remove both characters, as we cannot assume a Windows file path is always delimited or trailed with ""\"".

I will make the patch, and will test the all the expected results on Windows and Linux. That is, if I am not convinced this is no way to go (adding optional parameters and ""messing"" with an old formatting function).

== Alternatives ==

We could make untrailingslashpath() and trailingslashpath() which assumes a path string, and no extra argument. This would require, at least softly, a replace all over the code, where a path is to be (un)trailingslashed.

We could make untrailingbackslashit() and trailingbackslashit() instead, but this would force us to check either DIRECTORY_SEPARATOR or $is_win before selecting which function to use, bloating code all over the place. A good helper function should be a real help, especially in edge cases.
"	enhancement	new	normal	Awaiting Review	Filesystem	2.2	normal		has-patch	knutsp Ov3rfly