and fix another flaw in the singlecwd case when we get ftp://site.com/, also

from the #1739100 bug report

lib/ftp.c

@@ -3691,6 +3691,12 @@ CURLcode ftp_parse_url_path(struct connectdata *conn)
 
   case FTPFILE_SINGLECWD:
     /* get the last slash */
+    if(!path_to_use[0]) {
+      /* no dir, no file */
+      ftpc->dirdepth = 0;
+      ftp->file = NULL;
+      break;
+    }
     slash_pos=strrchr(cur_pos, '/');
     if(slash_pos || !*cur_pos) {
       ftpc->dirs = (char **)calloc(1, sizeof(ftpc->dirs[0]));
@@ -3773,7 +3779,7 @@ CURLcode ftp_parse_url_path(struct connectdata *conn)
     ftp->file = cur_pos;  /* the rest is the file name */
   }
 
-  if(*ftp->file) {
+  if(ftp->file && *ftp->file) {
     ftp->file = curl_easy_unescape(conn->data, ftp->file, 0, NULL);
     if(NULL == ftp->file) {
       freedirs(conn);

tests/data/Makefile.am

@@ -42,4 +42,4 @@ EXTRA_DIST = test1 test108 test117 test127 test20 test27 test34 test46	   \
  test405 test604 test605 test606 test607 test608 test609 test294 test295   \
  test296 test297 test298 test610 test611 test612 test406 test407 test408   \
  test409 test613 test614 test700 test701 test702 test704 test705 test703   \
- test706 test707 test350 test351 test352
+ test706 test707 test350 test351 test352 test353

tests/data/test353

@@ -0,0 +1,56 @@
+<testcase>
+<info>
+<keywords>
+FTP
+PASV
+LIST
+</keywords>
+</info>
+#
+# Server-side
+<reply>
+# When doing LIST, we get the default list output hard-coded in the test
+# FTP server
+<datacheck>
+total 20
+drwxr-xr-x   8 98       98           512 Oct 22 13:06 .
+drwxr-xr-x   8 98       98           512 Oct 22 13:06 ..
+drwxr-xr-x   2 98       98           512 May  2  1996 .NeXT
+-r--r--r--   1 0        1             35 Jul 16  1996 README
+lrwxrwxrwx   1 0        1              7 Dec  9  1999 bin -> usr/bin
+dr-xr-xr-x   2 0        1            512 Oct  1  1997 dev
+drwxrwxrwx   2 98       98           512 May 29 16:04 download.html
+dr-xr-xr-x   2 0        1            512 Nov 30  1995 etc
+drwxrwxrwx   2 98       1            512 Oct 30 14:33 pub
+dr-xr-xr-x   5 0        1            512 Oct  1  1997 usr
+</datacheck>
+</reply>
+
+#
+# Client-side
+<client>
+<server>
+ftp
+</server>
+ <name>
+FTP home dir list singlecwd
+ </name>
+ <command>
+ftp://%HOSTIP:%FTPPORT/ --ftp-method singlecwd
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<protocol>
+USER anonymous
+PASS ftp@example.com
+PWD
+EPSV
+TYPE A
+LIST
+QUIT
+</protocol>
+</verify>
+</testcase>