better handle destfn rename failures by setting and catching new_name…

…=None

sarracenia/flow/__init__.py

@@ -734,7 +734,7 @@ def sundew_getDestInfos(self, msg, currentFileOption, filename):
 
                         if destFileName == None or type(destFileName) != str:
                              logger.error( f"DESTFNSCRIPT {dfm} return value must be the new file name as a string. This one returned {destFileName}, ignoring")
-                             destFileName=filename
+                             return None
 
             elif spec == 'TIME':
                 timeSuffix = ':' + time.strftime("%Y%m%d%H%M%S", time.gmtime())
@@ -749,9 +749,8 @@ def sundew_getDestInfos(self, msg, currentFileOption, filename):
                     timeSuffix = ':' + parts[-1]
 
             else:
-                logger.error("Don't understand this DESTFN parameter: %s" %
-                             spec)
-                return filename
+                logger.error( f"invalid DESTFN parameter: {spec}" )
+                return None
         return destFileName + satnet + timeSuffix
 
 
@@ -1630,6 +1629,14 @@ def do_download(self) -> None:
                 self.worklist.ok.append(msg)
                 continue
 
+            if not 'new_dir' in msg or not msg['new_dir']:
+                self.reject(msg, 422, f"new_dir message field missing, do not know which directory to put file in. skipping." )
+                continue
+
+            if not 'new_file' in msg or not msg['new_file']:
+                self.reject(msg, 422, f"new_file message field missing, do not know name of file to write. skipping." )
+                continue
+
             new_path = msg['new_dir'] + os.path.sep + msg['new_file']
             new_file = msg['new_file']
 
@@ -2717,6 +2724,14 @@ def do_send(self):
 
         for msg in self.worklist.incoming:
 
+            if not 'new_dir' in msg or not msg['new_dir']:
+                self.reject(msg, 422, f"new_dir message field missing, do not know which directory to put file in. skipping." )
+                continue
+
+            if not 'new_file' in msg or not msg['new_file']:
+                self.reject(msg, 422, f"new_file message field missing, do not know name of file to write. skipping." )
+                continue
+
             # weed out non-file transfer operations that are configured to not be done.
             if 'fileOp' in msg:
                 if ('directory' in msg['fileOp']) and ('remove' in msg['fileOp']) and ( 'rmdir' not in self.o.fileEvents ):