bpo-40597: Allow email.contextmanager set_content() to set a null string. (GH-20542)
diff --git a/Lib/email/contentmanager.py b/Lib/email/contentmanager.py
index 2b4b875..b91fb0e 100644
--- a/Lib/email/contentmanager.py
+++ b/Lib/email/contentmanager.py
@@ -146,7 +146,7 @@
def normal_body(lines): return b'\n'.join(lines) + b'\n'
if cte==None:
# Use heuristics to decide on the "best" encoding.
- if max(len(x) for x in lines) <= policy.max_line_length:
+ if max((len(x) for x in lines), default=0) <= policy.max_line_length:
try:
return '7bit', normal_body(lines).decode('ascii')
except UnicodeDecodeError:
diff --git a/Lib/test/test_email/test_contentmanager.py b/Lib/test/test_email/test_contentmanager.py
index 64dca2d..f4f6bb7 100644
--- a/Lib/test/test_email/test_contentmanager.py
+++ b/Lib/test/test_email/test_contentmanager.py
@@ -303,6 +303,19 @@
self.assertEqual(m.get_payload(decode=True).decode('utf-8'), content)
self.assertEqual(m.get_content(), content)
+ def test_set_text_plain_null(self):
+ m = self._make_message()
+ content = ''
+ raw_data_manager.set_content(m, content)
+ self.assertEqual(str(m), textwrap.dedent("""\
+ Content-Type: text/plain; charset="utf-8"
+ Content-Transfer-Encoding: 7bit
+
+
+ """))
+ self.assertEqual(m.get_payload(decode=True).decode('utf-8'), '\n')
+ self.assertEqual(m.get_content(), '\n')
+
def test_set_text_html(self):
m = self._make_message()
content = "<p>Simple message.</p>\n"
diff --git a/Misc/NEWS.d/next/Library/2020-05-30-12-44-29.bpo-39384.Iqxy3q.rst b/Misc/NEWS.d/next/Library/2020-05-30-12-44-29.bpo-39384.Iqxy3q.rst
new file mode 100644
index 0000000..482ae62
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-05-30-12-44-29.bpo-39384.Iqxy3q.rst
@@ -0,0 +1 @@
+Fixed email.contentmanager to allow set_content() to set a null string.