urls: Also decode slashes in message IDs

In commit 2653fdb, we started encoding slashes in message IDs
presented to users. This allowed us to support message IDs containing
slashes, which are allowed per the RFC and have been seen in the wild.
However, we continue to store the original unencoded message IDs in the
database and unfortunately we neglected to reverse the decoding in the
functions for downloading patch diffs and mboxes. Address this now.

Signed-off-by: Stephen Finucane <[email protected]>
Fixes: 2653fdb ("urls: Encode slashes in message IDs")
Closes: #518
Cc: Siddhesh Poyarekar <[email protected]>
Cc: DJ Delorie <[email protected]>
(cherry picked from commit ddc4c7e)

Author: stephenfin

patchwork/models.py

@@ -387,6 +387,14 @@ def encoded_msgid(self):
         # [1] https://datatracker.ietf.org/doc/html/rfc3986.html#section-2
         return self.url_msgid.replace('/', '%2F')
 
+    @staticmethod
+    def decode_msgid(msgid):
+        """Decode an encoded msgid.
+
+        Reverses :mod:`~url_msgid` and :mod:`~encoded_msgid` operations.
+        """
+        return f"<{msgid.replace('%2F', '/')}>"
+
     def save(self, *args, **kwargs):
         # Modifying a submission via admin interface changes '\n' newlines in
         # message content to '\r\n'. We need to fix them to avoid problems,

patchwork/views/patch.py

@@ -40,7 +40,7 @@ def patch_list(request, project_id):
 
 def patch_detail(request, project_id, msgid):
     project = get_object_or_404(Project, linkname=project_id)
-    db_msgid = f"<{msgid.replace('%2F', '/')}>"
+    db_msgid = Patch.decode_msgid(msgid)
 
     # redirect to cover letters where necessary
     try:
@@ -152,7 +152,7 @@ def patch_detail(request, project_id, msgid):
 
 
 def patch_raw(request, project_id, msgid):
-    db_msgid = '<%s>' % msgid
+    db_msgid = Patch.decode_msgid(msgid)
     project = get_object_or_404(Project, linkname=project_id)
     patch = get_object_or_404(Patch, project_id=project.id, msgid=db_msgid)
 
@@ -166,7 +166,7 @@ def patch_raw(request, project_id, msgid):
 
 
 def patch_mbox(request, project_id, msgid):
-    db_msgid = '<%s>' % msgid
+    db_msgid = Patch.decode_msgid(msgid)
     project = get_object_or_404(Project, linkname=project_id)
     patch = get_object_or_404(Patch, project_id=project.id, msgid=db_msgid)
     series_id = request.GET.get('series')