Doc string clarification in file-directory-p

* src/fileio.c (Ffile_directory_p): Mention that "" is a special
case (bug#43375).

1 files changed, 5 insertions, 0 deletions

diff --git a/src/fileio.c b/src/fileio.c
index 1e4ca82e5f3..6d0bafa8cf9 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -2919,6 +2919,11 @@ DEFUN ("file-directory-p", Ffile_directory_p, Sfile_directory_p, 1, 1, 0,
        doc: /* Return t if FILENAME names an existing directory.
 Return nil if FILENAME does not name a directory, or if there
 was trouble determining whether FILENAME is a directory.
+
+As a special case, this function will also return t if FILENAME is the
+empty string (\"\").  This quirk is due to Emacs interpreting the
+empty string (in some cases) as the current directory.
+
 Symbolic links to directories count as directories.
 See `file-symlink-p' to distinguish symlinks.  */)
   (Lisp_Object filename)