- The libcurl FTP code now returns CURLE_REMOTE_FILE_NOT_FOUND error when SIZE

gets a 550 response back for the cases where a download (or NOBODY) is
  wanted. It still allows a 550 as response if the SIZE is used as part of an
  upload process (like if resuming an upload is requested and the file isn't
  there before the upload). I also modified the FTP test server and a few test
  cases accordingly to match this modified behavior.

tests/data/test118

@@ -9,6 +9,9 @@ FAILURE
 </info>
 # Server-side
 <reply>
+<size>
+1
+</size>
 <servercmd>
 REPLY RETR 314 bluah you f00l!
 REPLY EPSV 314 bluah you f00l!

tests/data/test533

@@ -45,10 +45,8 @@ CWD path
 EPSV
 TYPE I
 SIZE 533
-RETR 533
 EPSV
 SIZE 533
-RETR 533
 QUIT
 </protocol>
 </verify>

tests/data/test534

@@ -45,7 +45,6 @@ CWD path
 EPSV
 TYPE I
 SIZE 534
-RETR 534
 QUIT
 </protocol>
 </verify>

tests/data/test546

@@ -19,8 +19,6 @@ works
 </data>
 
 <servercmd>
-REPLY RETR 550 the file doesn't exist
-COUNT RETR 1
 REPLY SIZE 550 Can't check for file existence
 COUNT SIZE 1
 </servercmd>
@@ -52,7 +50,6 @@ CWD path
 EPSV
 TYPE I
 SIZE 546
-RETR 546
 EPSV
 SIZE 546
 RETR 546

tests/ftpserver.pl

@@ -389,12 +389,14 @@ sub SIZE_command {
 
     my $size = $data[0];
 
-    if($size) {
+    if($size ne "") {
+        # we check for "" to be able to explictly set the size to 0 and yet have
+        # that send a 213
         if($size > -1) {
             sendcontrol "213 $size\r\n";
         }
         else {
-            sendcontrol "550 $testno: No such file or directory.\r\n";
+            sendcontrol "350 $testno: SIZE is not supported.\r\n";
         }
     }
     else {
@@ -407,7 +409,7 @@ sub SIZE_command {
             sendcontrol "213 $size\r\n";
         }
         else {
-            sendcontrol "550 $testno: No such file or directory.\r\n";
+            sendcontrol "350 $testno: SIZE is not supported.\r\n";
         }
     }
     return 0;