fix errant this_columns

Author: Ben Kandel

pandas/io/parsers.py

@@ -2083,10 +2083,10 @@ def _infer_columns(self):
                     # We have an empty file, so check
                     # if columns are provided. That will
                     # serve as the 'line' for parsing
-                    if have_mi_columns:
+                    if have_mi_columns and hr > 0:
                         if clear_buffer:
                             self._clear_buffer()
-                        columns.append([None] * len(this_columns))
+                        columns.append([None] * len(columns[-1]))
                         return columns, num_original_columns
 
                     if not self.names:

pandas/parser.pyx

@@ -715,7 +715,7 @@ cdef class TextReader:
 
                 # e.g., if header=3 and file only has 2 lines
                 elif (self.parser.lines < hr + 1
-                    and not isinstance(self.orig_header, list)) or (
+                      and not isinstance(self.orig_header, list)) or (
                             self.parser.lines < hr):
                     msg = self.orig_header
                     if isinstance(msg, list):