parsemail: Ensure that the patch order cannot be None

find_patch_order() was starting with order = None and trying to retrieve
the order from the previous revision. That doesn't work when there's no
previous revision, because patchwork didn't know about series when the
previous patch was sent.

The test case triggering the failure is actually a bit involved. It
needs series as reply to a couple of revision of a single patch, with
the part of thread before series support. The test case has the full
story.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>

patchwork/bin/parsemail.py

@@ -439,10 +439,9 @@ def find_previous_patch(revision, order, refs):
 
     return None
 
-def find_patch_order(revisions, previous_patch):
+def find_patch_order(revisions, previous_patch, order):
     # cycle through revisions starting by the more recent one and find
     # the revision where previous_patch is
-    order = None
     for revision in revisions:
         try:
             order = SeriesRevisionPatch.objects.get(revision=revision,
@@ -477,7 +476,7 @@ def find_series_for_mail(project, name, msgid, is_patch, order, refs):
         if is_patch:
             previous_patch = find_previous_patch(revision, order, refs)
             if previous_patch:
-                order = find_patch_order(revisions, previous_patch)
+                order = find_patch_order(revisions, previous_patch, order)
                 revision = revision.duplicate(exclude_patches=(order,))
                 # series has been updated, grab the new instance
                 series = revision.series

patchwork/tests/test_series.py

@@ -400,6 +400,19 @@ def testNoCoverLetterUpdateLen3Patch3(self):
 class SinglePatchUpdatesVariousCornerCasesTest(TestCase):
     fixtures = ['default_states', 'default_events']
 
+    def setMessageId(self, mail, msgid):
+        del mail['Message-Id']
+        mail['Message-Id'] = msgid
+
+    def setParentMail(self, mail, parent_mail, references=[]):
+        del mail['References']
+        del mail['In-Reply-To']
+        mail['In-Reply-To'] = parent_mail.get('Message-Id')
+        if not references:
+            mail['References'] = parent_mail.get('Message-Id')
+            return
+        mail['References'] = ' '.join([m.get('Message-Id') for m in references])
+
     def testSinglePatchUpdatesNotSerialized(self):
         """ + patch v1
             +--> patch v2
@@ -473,6 +486,56 @@ def testSinglePatchUpdateNoCoverLetterNoSeriesMarker(self):
         self.assertEqual(patches[0].name, '[1/2] ' + defaults.patch_name)
         self.assertEqual(patches[1].name, '[v2] ' + defaults.patch_name)
 
+    def testSeriesAsReplyofSinglePatchCrossSeriesAwarePatchwork(self):
+        """ + initia_patch                     \
+            +--+ reply_1                        | Before patchwork knew
+               +--+ patch_v2                    | about series
+                  +--+ reply_2                 /
+                     +--+ cover letter (0/3)   \
+                        +--> patch 1/3          | After patchwork knew
+                        +--> patch 2/3          | about series
+                        +--> patch 3/3         /
+        """
+        initial_series = TestSeries(1, has_cover_letter=False)
+        mails = initial_series.create_mails()
+        initial_patch = mails[0]
+        self.setMessageId(initial_patch, 'initial_patch')
+
+        reply_1 = initial_series.create_reply(initial_patch)
+        mails.append(reply_1)
+        self.setMessageId(reply_1, 'reply_1')
+
+        patch_v2 = initial_series.create_patch(in_reply_to=reply_1,
+                                               subject_prefix="PATCH v2")
+        mails.append(patch_v2)
+
+        reply_2 = initial_series.create_reply(patch_v2)
+        mails.append(reply_2)
+        self.setMessageId(reply_2, 'reply_2')
+
+        initial_series.insert(mails)
+
+        # deleting the Series objects so far simulates the transition to
+        # a series-aware patchwork from a previous version not creating
+        # Series objects.
+        Series.objects.all().delete()
+
+        series = TestSeries(3)
+        series_mails = series.create_mails()
+        self.setMessageId(series_mails[0], 'cover_letter')
+        self.setParentMail(series_mails[0], reply_2)
+        for mail in series_mails[1:]:
+            self.setParentMail(mail, series_mails[0],
+                    references=(reply_2, series_mails[0]))
+        series.insert(series_mails)
+
+        series = Series.objects.all()
+        self.assertEqual(len(series), 1)
+        revisions = series[0].revisions()
+        # FIXME: We don't treat a series sent as a reply as a single
+        # entity. Something that will need fixing.
+        self.assertEqual(len(revisions), 3)
+
 #
 # New version of a full series (separate mail thread)
 #