bpo-36226: Ignore multipart check for headersonly

grische · grische · commit 6dd5999223ae · 2019-09-05T12:15:23.000+02:00
root cannot be a list if only the headers have been passed on and are
being parsed.

This fixes false MultipartInvariantViolationDefects
diff --git a/Lib/email/feedparser.py b/Lib/email/feedparser.py
@@ -189,6 +189,7 @@ def close(self):
         assert not self._msgstack
         # Look for final set of defects
         if root.get_content_maintype() == 'multipart' \
+               and not self._headersonly \
                and not root.is_multipart():
             defect = errors.MultipartInvariantViolationDefect()
             self.policy.handle_defect(root, defect)
diff --git a/Lib/test/test_email/test_parser.py b/Lib/test/test_email/test_parser.py
@@ -5,6 +5,12 @@
 from email.policy import default
 from test.test_email import TestEmailBase
 
+class TestFeedParser(TestEmailBase):
+    def test_multipart_message_with_headers_only(self):
+        import email.parser
+        header = 'Content-Type: multipart/related; boundary="==="\r\n\r\n'
+        msg = email.parser.Parser().parsestr(header, headersonly=True)
+        self.assertDefectsEqual(msg.defects, [])
 
 class TestCustomMessage(TestEmailBase):
 
diff --git a/Misc/NEWS.d/next/Library/2019-09-05-12-13-11.bpo-36226.J5mcDO.rst b/Misc/NEWS.d/next/Library/2019-09-05-12-13-11.bpo-36226.J5mcDO.rst
@@ -0,0 +1,2 @@
+Fixes false MultipartInvariantViolationDefects which were triggered when
+only headers of a multipart message were parsed.

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+Fixes false MultipartInvariantViolationDefects which were triggered when`
	`2`	`+only headers of a multipart message were parsed.`