svn export misbehaves from WC with file externals

If this is an issue that should be sent to the bugtracker or a different
mailing list, please let me know and I'm happy to do so.

We're using svn:externals properties to reference files within another part
of the same repo, and the documented behavior of 'svn export' when using a
PATH as the first argument fails in cases where the parent directory of the
SVN external is implicitly created. This is in contrast to doing the same
export when the first argument is a URL, including a relative-SVN-URL.

I've included a minimal test case below demonstrating the problem.

This poses an issue for environments using svn:externals in this way that
also wish to perform an export with the contents of the WC, which may
include yet-uncommitted changes, or simply a mixed-rev checkout of some
sort.

Test case, assumes $HOME/src/svn-example is empty or non-existent:

mkdir -p "$HOME/src/svn-example"
cd "$HOME/src/svn-example"
svnadmin create repo
svn co "file://$HOME/src/svn-example/repo" wc
cd wc
mkdir externals dir
echo "I am the source for an external file" > externals/ext-file
svn add externals dir
svn ps svn:externals '^/externals/ext-file subdir/ext-file' dir
svn ci -m "Initial commit"
svn up
echo "PERFORMING WC EXPORT.."
svn export dir ../export-will-fail
echo "PERFORMING RELATIVE URI EXPORT.."
svn export ^/dir ../export-will-work

# End test case.

-- 
Josh