[PATCH] parser: Don't crash when From: is list email but has weird mangle format

[Andrew Donnellan]

get_original_sender() tries to demangle DMARC-mangled From headers, in
the case where the email's From address is the list address. It knows how
to handle Google Groups and Mailman style mangling, where the original
submitter's name will be turned into e.g. "Andrew Donnellan via
linuxppc-dev".

If an email has the From header set to the list address but has a name that
doesn't include " via ", we'll throw an exception because stripped_name
hasn't been set. Sometimes this is because the list name is seemingly
empty, resulting in a mangled name like "Andrew Donnellan via"
without the space after "via" that we detect. Handle this as well as we can
instead, and add a test.

Fixes: 8279a84238c10 ("parser: Unmangle From: headers that have been mangled for DMARC purposes")
Reported-by: Jeremy Kerr <jk at ozlabs.org>
Signed-off-by: Andrew Donnellan <ajd at linux.ibm.com>

---

Backport to stable?
---
 patchwork/parser.py            |  7 +++++++
 patchwork/tests/test_parser.py | 23 +++++++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/patchwork/parser.py b/patchwork/parser.py
index a09fd754c4be..dce03a4ff827 100644
--- a/patchwork/parser.py
+++ b/patchwork/parser.py
@@ -373,6 +373,13 @@ def get_original_sender(mail, name, email):
         # Mailman uses the format "<name> via <list>"
         # Google Groups uses "'<name>' via <list>"
         stripped_name = name[:name.rfind(' via ')].strip().strip("'")
+    elif name.endswith(' via'):
+        # Sometimes this seems to happen (perhaps if Mailman isn't set up with
+        # any list name)
+        stripped_name = name[:name.rfind(' via')].strip().strip("'")
+    else:
+        # We've hit a format that we don't expect
+        stripped_name = None
 
     original_from = clean_header(mail.get('X-Original-From', ''))
     if original_from:
diff --git a/patchwork/tests/test_parser.py b/patchwork/tests/test_parser.py
index f5631bee8329..a60eb6b4bac9 100644
--- a/patchwork/tests/test_parser.py
+++ b/patchwork/tests/test_parser.py
@@ -366,6 +366,29 @@ class SenderCorrelationTest(TestCase):
         self.assertEqual(person_b._state.adding, False)
         self.assertEqual(person_b.id, person_a.id)
 
+    def test_weird_dmarc_munging(self):
+        project = create_project()
+        real_sender = 'Existing Sender <existing at example.com>'
+        munged_sender1 = "'Existing Sender' via <{}>".format(project.listemail)
+        munged_sender2 = "'Existing Sender' <{}>".format(project.listemail)
+
+        # Unmunged author
+        mail = self._create_email(real_sender)
+        person_a = get_or_create_author(mail, project)
+        person_a.save()
+
+        # Munged with no list name
+        mail = self._create_email(munged_sender1, None, None, real_sender)
+        person_b = get_or_create_author(mail, project)
+        self.assertEqual(person_b._state.adding, False)
+        self.assertEqual(person_b.id, person_a.id)
+
+        # Munged with no 'via'
+        mail = self._create_email(munged_sender2, None, None, real_sender)
+        person_b = get_or_create_author(mail, project)
+        self.assertEqual(person_b._state.adding, False)
+        self.assertEqual(person_b.id, person_a.id)
+
 
 class SeriesCorrelationTest(TestCase):
     """Validate correct behavior of find_series."""
-- 
2.20.1