mbox series
Message ID20260604141826.2998337-3-robin@jarry.cc
StateNew
Delegate
ArchivedNo
Headers
show
Return-Path: <robin@jarry.cc>
Received: from ringo (2a01cb00021ec0002e23edbec21b0e73.ipv6.abo.wanadoo.fr
 [IPv6:2a01:cb00:21e:c000:2e23:edbe:c21b:e73])
	by patches.jarry.cc (Postfix) with ESMTP id 6A1441BC434D
	for <pw@patches.jarry.cc>; Thu, 04 Jun 2026 16:18:29 +0200 (CEST)
From: Robin Jarry <robin@jarry.cc>
To: pw@patches.jarry.cc
Subject: [PATCH v3 02/16] parsemail: fix SeriesReference race with concurrent
 delivery
Date: Thu,  4 Jun 2026 16:18:11 +0200
Message-ID: <20260604141826.2998337-3-robin@jarry.cc>
X-Mailer: git-send-email 2.54.0
In-Reply-To: <20260604141826.2998337-1-robin@jarry.cc>
References: <20260604141826.2998337-1-robin@jarry.cc>
MIME-Version: 1.0
List-ID: <pw.jarry.cc>
Content-Transfer-Encoding: 8bit
Series
Implement forge bidirectional sync
github_branchpatchwork/implement-forge-bidirectional-sync-c
github_prhttps://github.com/rjarry/patchwork/pull/4

Commit Message

Robin JarryJun. 4, 2026, 16:18. UTC
[v3,02/16] parsemail: fix SeriesReference race with concurrent delivery

When multiple parsemail processes run in parallel (e.g. postfix
delivering several messages from the same series at once), two
processes can try to create a SeriesReference for the same msgid
simultaneously. The second one fails with an IntegrityError:

  django.db.utils.IntegrityError: duplicate key value violates
  unique constraint "patchwork_seriesreference_project_id_msgid_..."
  DETAIL: Key (project_id, msgid)=(2, <...>) already exists.

This can result in incomplete series that never reach the
"received_all" state because the failed parsemail invocation
prevents one of the patches from being recorded.

The existing get/create pattern has a classic TOCTOU race: the get
succeeds (no reference found), but by the time create runs, another
process has already inserted the row. Replace both the try/get/
except/create block and the bare create call with get_or_create
which handles the race atomically at the database level.

Signed-off-by: Robin Jarry <robin@jarry.cc>
---
 patchwork/parser.py                           | 30 +++++++++----------
 .../parsemail-race-fix-e5f6g7h8i9j0k1l2.yaml  |  5 ++++
 2 files changed, 19 insertions(+), 16 deletions(-)
 create mode 100644 releasenotes/notes/parsemail-race-fix-e5f6g7h8i9j0k1l2.yaml

Patch

mbox series 
diff --git a/patchwork/parser.py b/patchwork/parser.py
index c33ada8d7d42..fafa47ba9e78 100644
--- a/patchwork/parser.py
+++ b/patchwork/parser.py
@@ -1336,20 +1336,18 @@ def parse_mail(mail, list_id=None):
                         # later one.
                         for ref in refs + [msgid]:
                             ref = ref[:255]
-                            # we don't want duplicates
-                            try:
-                                # we could have a ref to a previous series.
-                                # (For example, a series sent in reply to
-                                # another series.) That should not create a
-                                # series ref for this series, so check for the
-                                # msg-id only, not the msg-id/series pair.
-                                SeriesReference.objects.get(
-                                    msgid=ref, project=project
-                                )
-                            except SeriesReference.DoesNotExist:
-                                SeriesReference.objects.create(
-                                    msgid=ref, project=project, series=series
-                                )
+                            # We could have a ref to a previous series. (For
+                            # example, a series sent in reply to another
+                            # series.) That should not create a series ref for
+                            # this series, so check for the msg-id only, not
+                            # the msg-id/series pair. Use get_or_create to
+                            # avoid races when multiple parsemail processes run
+                            # in parallel.
+                            SeriesReference.objects.get_or_create(
+                                msgid=ref,
+                                project=project,
+                                defaults={'series': series},
+                            )
 
                         # attempt to pull the series in again, raising an
                         # exception if we lost the race when creating a series
@@ -1436,8 +1434,8 @@ def parse_mail(mail, list_id=None):
                 # we don't save the in-reply-to or references fields
                 # for a cover letter, as they can't refer to the same
                 # series
-                SeriesReference.objects.create(
-                    msgid=msgid, project=project, series=series
+                SeriesReference.objects.get_or_create(
+                    msgid=msgid, project=project, defaults={'series': series}
                 )
 
             with transaction.atomic():
diff --git a/releasenotes/notes/parsemail-race-fix-e5f6g7h8i9j0k1l2.yaml b/releasenotes/notes/parsemail-race-fix-e5f6g7h8i9j0k1l2.yaml
new file mode 100644
index 000000000000..f0869819538b
--- /dev/null
+++ b/releasenotes/notes/parsemail-race-fix-e5f6g7h8i9j0k1l2.yaml
@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Fix a race condition in SeriesReference creation during concurrent
+    email delivery.