commit ef5bb25e2d6147cd44be9c9b166525fb30485be0
author Batuhan Taşkaya <47358913+isidentical@users.noreply.github.com> Thu May 23 04:13:16 2019 +0300
committer R. David Murray <rdmurray@bitdance.com> Wed May 22 21:13:16 2019 -0400
tree 34b3fa59b4861461fab7223207c8605b75e88ec6
parent 6bc5917903b722bdd0e5d3020949f26fec5dfe9a

bpo-27737: Allow whitespace only headers encoding (#13478)

Lib/email/header.py

diff --git a/Lib/email/header.py b/Lib/email/header.py
index 7b30a03..4ab0032 100644
--- a/Lib/email/header.py
+++ b/Lib/email/header.py
@@ -431,7 +431,7 @@
         if end_of_line != (' ', ''):
             self._current_line.push(*end_of_line)
         if len(self._current_line) > 0:
-            if self._current_line.is_onlyws():
+            if self._current_line.is_onlyws() and self._lines:
                 self._lines[-1] += str(self._current_line)
             else:
                 self._lines.append(str(self._current_line))