Fix glob single file bug

azure/datalake/store/multithread.py

@@ -195,26 +195,42 @@ def clear_saved():
     def hash(self):
         return self._name
 
+
+
     def _setup(self):
         """ Create set of parameters to loop over
         """
-        if "*" not in self.rpath:
-            rfiles = self.client._adlfs.walk(self.rpath, details=True, invalidate_cache=True)
-        else:
+
+        def is_glob_path(path):
+            path = AzureDLPath(path).trim()
+            prefix = path.globless_prefix
+            return not path == prefix
+
+        if is_glob_path(self.rpath):
             rfiles = self.client._adlfs.glob(self.rpath, details=True, invalidate_cache=True)
+        else:
+            rfiles = self.client._adlfs.walk(self.rpath, details=True, invalidate_cache=True)
 
-        if len(rfiles) == 1 and self.client._adlfs.info(self.rpath)['type'] == 'FILE':
+
+        if len(rfiles) == 0:
+            raise ValueError('No files to download')
+
+        # If only one file is returned we are not sure whether user specified a dir or a file to download,
+        # since walk gives the same result for both i.e walk("DirWithsingleFile") == walk("DirWithSingleFile\SingleFile)
+        # If user specified a file in rpath,
+        # then we want to download the file into lpath directly and not create another subdir for that.
+        # If user specified a dir that happens to contain only one file, we want to create the dir as well under lpath.
+        if len(rfiles) == 1 and not is_glob_path(self.rpath) and self.client._adlfs.info(self.rpath)['type'] == 'FILE':
             if os.path.exists(self.lpath) and os.path.isdir(self.lpath):
                 file_pairs = [(os.path.join(self.lpath, os.path.basename(rfiles[0]['name'] + '.inprogress')),
                                rfiles[0])]
             else:
                 file_pairs = [(self.lpath, rfiles[0])]
-        elif len(rfiles) >= 1:
+        else:
             local_rel_rpath = str(AzureDLPath(self.rpath).trim().globless_prefix)
             file_pairs = [(os.path.join(self.lpath, os.path.relpath(f['name'] +'.inprogress', local_rel_rpath)), f)
                           for f in rfiles]
-        else:
-            raise ValueError('No files to download')
+
 
         # this property is used for internal validation
         # and should not be referenced directly by public callers
@@ -231,6 +247,7 @@ def _setup(self):
                 self.client.submit(rfile['name'], lfile, rfile['length'])
 
         return existing_files
+
     def run(self, nthreads=None, monitor=True):
         """ Populate transfer queue and execute downloads