From patchwork Sat Dec  7 16:46:18 2019
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
X-Patchwork-Submitter: Mete Polat <metepolat2000@gmail.com>
X-Patchwork-Id: 1205489
Return-Path: 
 <patchwork-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org>
X-Original-To: incoming@patchwork.ozlabs.org
Delivered-To: patchwork-incoming@bilbo.ozlabs.org
Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2])
	(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
	key-exchange X25519 server-signature RSA-PSS (4096 bits))
	(No client certificate requested)
	by ozlabs.org (Postfix) with ESMTPS id 47Vb4C4n76z9sPL
	for <incoming@patchwork.ozlabs.org>;
	Sun,  8 Dec 2019 03:48:11 +1100 (AEDT)
Authentication-Results: ozlabs.org;
	dmarc=fail (p=none dis=none) header.from=gmail.com
Authentication-Results: ozlabs.org;
	dkim=fail reason="signature verification failed" (2048-bit key;
	unprotected) header.d=gmail.com header.i=@gmail.com
	header.b="dwexzDPy"; dkim-atps=neutral
Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3])
	by lists.ozlabs.org (Postfix) with ESMTP id 47Vb4C36qdzDq5k
	for <incoming@patchwork.ozlabs.org>;
	Sun,  8 Dec 2019 03:48:11 +1100 (AEDT)
X-Original-To: patchwork@lists.ozlabs.org
Delivered-To: patchwork@lists.ozlabs.org
Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized)
	smtp.mailfrom=gmail.com (client-ip=2a00:1450:4864:20::342;
	helo=mail-wm1-x342.google.com; envelope-from=metepolat2000@gmail.com;
	receiver=<UNKNOWN>)
Authentication-Results: lists.ozlabs.org;
	dmarc=pass (p=none dis=none) header.from=gmail.com
Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key;
	unprotected) header.d=gmail.com header.i=@gmail.com
	header.b="dwexzDPy"; dkim-atps=neutral
Received: from mail-wm1-x342.google.com (mail-wm1-x342.google.com
	[IPv6:2a00:1450:4864:20::342])
	(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
	key-exchange X25519 server-signature RSA-PSS (2048 bits)
	server-digest SHA256) (No client certificate requested)
	by lists.ozlabs.org (Postfix) with ESMTPS id 47Vb315K5GzDqYY
	for <patchwork@lists.ozlabs.org>;
	Sun,  8 Dec 2019 03:47:09 +1100 (AEDT)
Received: by mail-wm1-x342.google.com with SMTP id t14so10448192wmi.5
	for <patchwork@lists.ozlabs.org>;
	Sat, 07 Dec 2019 08:47:09 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025;
	h=from:to:cc:subject:date:message-id:in-reply-to:references
	:mime-version:content-transfer-encoding;
	bh=aP6LIah9w5Z2DWpHulQ8fBEbqrJBsfZikk3PZoQDFUI=;
	b=dwexzDPyePRoLJGgtS4rMCqmbm4XRqKayFV1odOCre9loEn0zM43zDHgIE4nu3XH5Q
	XfQPrVpXTfiflea5qZQt0GaFHZhJwGLg4WQfAAlvGNe1iS6Kng3CAVyWPA4prBRrQ0LQ
	/ABo7yxlE5yOloFyCGIWdCeL3+FzyaE+TUAp7SDH6rzKOo3xqnMoy5Sb5Icib+rT0o9M
	gMWP17hKOf4jj1nwTnHS8r+JOoLWBQbeucvg3Eok5JjXL0M4LCQHvUI0hu4Kr/pg4nKj
	RE9WF4Z7R1ovwD8rJ5NnJbOmerNJmtJZCA1IO/DmzAyONyzocVSpxYhmqesfkWfAXVIr
	WMrg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
	d=1e100.net; s=20161025;
	h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to
	:references:mime-version:content-transfer-encoding;
	bh=aP6LIah9w5Z2DWpHulQ8fBEbqrJBsfZikk3PZoQDFUI=;
	b=Z9Kqe5CpWE8aw8jCPCxx6BFA/n72LfsoIUw/d007iXspNn//t5M5D9q0LnQgsoEMtA
	Z/0vr6fN92JgnPyDy6Jg+d0pogtNEzRD3cbuSxk8NbXCRnF9pJqQ/YuKhuX75rUzTxeE
	bZL77qBQojPGIHqVc8BIZELp5NjkOvTMkHYLTInDUmrDysh25w1LHHkR6WaDUxA93hi5
	NwwZs1wLdoQCcT5tCBKxofkslqVkysNR4CV3d44604sMquitqcHIIBHmD/qUay7pM7Kz
	Yws2VLh3tZt1zZtTLFYFvWBkLMBA0su5bONyrFaqIY/ddEgGMV8vzUMD8asOyDEckAV9
	f6BA==
X-Gm-Message-State: APjAAAWMW4h6ufPgN96IhkEjIYcZ1NQSFwIJXqP8xvHfPh5zivS/E5vJ
	8XSeFQa4OnVvu63p0cv8gp15x2rIFq4=
X-Google-Smtp-Source: 
 APXvYqxDuCAXHftjzOomd7RrD7wqWK0jXNEbGllyllWGaGWcqwBAPuLPObObP+D53Y2HTrkz1GWnwQ==
X-Received: by 2002:a1c:7d93:: with SMTP id
	y141mr16669549wmc.111.1575737223027;
	Sat, 07 Dec 2019 08:47:03 -0800 (PST)
Received: from Metes-MBP.fritz.box
	(aftr-62-216-202-157.dynamic.mnet-online.de. [62.216.202.157])
	by smtp.gmail.com with ESMTPSA id
	u22sm22083886wru.30.2019.12.07.08.47.02
	(version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);
	Sat, 07 Dec 2019 08:47:02 -0800 (PST)
From: Mete Polat <metepolat2000@gmail.com>
To: patchwork@lists.ozlabs.org
Subject: [PATCH 1/4] ui, templates: Combine series and related row
Date: Sat,  7 Dec 2019 17:46:18 +0100
Message-Id: <20191207164621.24234-2-metepolat2000@gmail.com>
X-Mailer: git-send-email 2.24.0
In-Reply-To: <20191207164621.24234-1-metepolat2000@gmail.com>
References: <20191207164621.24234-1-metepolat2000@gmail.com>
MIME-Version: 1.0
X-BeenThere: patchwork@lists.ozlabs.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Patchwork development <patchwork.lists.ozlabs.org>
List-Unsubscribe: <https://lists.ozlabs.org/options/patchwork>,
	<mailto:patchwork-request@lists.ozlabs.org?subject=unsubscribe>
List-Archive: <http://lists.ozlabs.org/pipermail/patchwork/>
List-Post: <mailto:patchwork@lists.ozlabs.org>
List-Help: <mailto:patchwork-request@lists.ozlabs.org?subject=help>
List-Subscribe: <https://lists.ozlabs.org/listinfo/patchwork>,
	<mailto:patchwork-request@lists.ozlabs.org?subject=subscribe>
Cc: ralf.ramsauer@oth-regensburg.de
Errors-To: patchwork-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org
Sender: "Patchwork"
	<patchwork-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org>

Move the series patch list from row 'Related' to 'Series'. This allows
us to use the 'Related' row for actually showing submission relations
instead.

Signed-off-by: Mete Polat <metepolat2000@gmail.com>
Reviewed-by: Stephen Finucane <stephen@that.guru>
---
 htdocs/css/style.css                          |  2 +-
 patchwork/templates/patchwork/submission.html | 69 +++++++++----------
 2 files changed, 33 insertions(+), 38 deletions(-)

diff --git a/htdocs/css/style.css b/htdocs/css/style.css
index b9fb9eb302f9..243caa0d968a 100644
--- a/htdocs/css/style.css
+++ b/htdocs/css/style.css
@@ -192,7 +192,7 @@ table.patchmeta tr th, table.patchmeta tr td {
     vertical-align: top;
 }
 
-.patchrelations ul {
+.submissionlist ul {
     list-style-type: none;
     padding: 0;
     margin: 0;
diff --git a/patchwork/templates/patchwork/submission.html b/patchwork/templates/patchwork/submission.html
index 2706a5535605..77a2711ab5b4 100644
--- a/patchwork/templates/patchwork/submission.html
+++ b/patchwork/templates/patchwork/submission.html
@@ -9,7 +9,7 @@
 
 {% block body %}
 <script>
-function toggle_div(link_id, headers_id)
+function toggle_div(link_id, headers_id, label_show, label_hide)
 {
     var link = document.getElementById(link_id)
     var headers = document.getElementById(headers_id)
@@ -17,10 +17,10 @@ function toggle_div(link_id, headers_id)
     var hidden = headers.style['display'] == 'none';
 
     if (hidden) {
-        link.innerHTML = 'hide';
+        link.innerHTML = label_hide || 'hide';
         headers.style['display'] = 'block';
     } else {
-        link.innerHTML = 'show';
+        link.innerHTML = label_show || 'show';
         headers.style['display'] = 'none';
     }
 
@@ -74,42 +74,37 @@ function toggle_div(link_id, headers_id)
   <th>Series</th>
   <td>
    <a href="{% url 'patch-list' project_id=project.linkname %}?series={{ submission.series.id }}">
-    {{ submission.series }}
-   </a>
-  </td>
- </tr>
- <tr>
-  <th>Related</th>
-  <td>
-   <a id="togglepatchrelations"
-      href="javascript:toggle_div('togglepatchrelations', 'patchrelations')"
-   >show</a>
-   <div id="patchrelations" class="patchrelations" style="display:none;">
+    {{ submission.series.name }}
+   </a> |
+   <a id="togglepatchseries"
+      href="javascript:toggle_div('togglepatchseries', 'patchseries', 'expand', 'collapse')"
+   >expand</a>
+   <div id="patchseries" class="submissionlist" style="display:none;">
     <ul>
-    {% with submission.series.cover_letter as cover %}
-     <li>
-     {% if cover %}
-      {% if cover == submission %}
-       {{ cover.name|default:"[no subject]"|truncatechars:100 }}
-      {% else %}
-      <a href="{% url 'cover-detail' project_id=project.linkname msgid=cover.url_msgid %}">
-       {{ cover.name|default:"[no subject]"|truncatechars:100 }}
-      </a>
-      {% endif %}
-     {% endif %}
-     </li>
-    {% endwith %}
-    {% for sibling in submission.series.patches.all %}
-     <li>
-      {% if sibling == submission %}
-       {{ sibling.name|default:"[no subject]"|truncatechars:100 }}
-      {% else %}
-      <a href="{% url 'patch-detail' project_id=project.linkname msgid=sibling.url_msgid %}">
-       {{ sibling.name|default:"[no subject]"|truncatechars:100 }}
-      </a>
+     {% with submission.series.cover_letter as cover %}
+      <li>
+      {% if cover %}
+       {% if cover == submission %}
+        {{ cover.name|default:"[no subject]"|truncatechars:100 }}
+       {% else %}
+       <a href="{% url 'cover-detail' project_id=project.linkname msgid=cover.url_msgid %}">
+        {{ cover.name|default:"[no subject]"|truncatechars:100 }}
+       </a>
+       {% endif %}
       {% endif %}
-     </li>
-    {% endfor %}
+      </li>
+     {% endwith %}
+     {% for sibling in submission.series.patches.all %}
+      <li>
+       {% if sibling == submission %}
+        {{ sibling.name|default:"[no subject]"|truncatechars:100 }}
+       {% else %}
+       <a href="{% url 'patch-detail' project_id=project.linkname msgid=sibling.url_msgid %}">
+        {{ sibling.name|default:"[no subject]"|truncatechars:100 }}
+       </a>
+       {% endif %}
+      </li>
+     {% endfor %}
     </ul>
    </div>
   </td>

From patchwork Sat Dec  7 16:46:19 2019
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
X-Patchwork-Submitter: Mete Polat <metepolat2000@gmail.com>
X-Patchwork-Id: 1205487
Return-Path: 
 <patchwork-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org>
X-Original-To: incoming@patchwork.ozlabs.org
Delivered-To: patchwork-incoming@bilbo.ozlabs.org
Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3])
	(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
	key-exchange X25519 server-signature RSA-PSS (4096 bits)
	server-digest SHA256) (No client certificate requested)
	by ozlabs.org (Postfix) with ESMTPS id 47Vb3b017kz9sNx
	for <incoming@patchwork.ozlabs.org>;
	Sun,  8 Dec 2019 03:47:39 +1100 (AEDT)
Authentication-Results: ozlabs.org;
	dmarc=fail (p=none dis=none) header.from=gmail.com
Authentication-Results: ozlabs.org;
	dkim=fail reason="signature verification failed" (2048-bit key;
	unprotected) header.d=gmail.com header.i=@gmail.com
	header.b="C3BNcfDo"; dkim-atps=neutral
Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3])
	by lists.ozlabs.org (Postfix) with ESMTP id 47Vb3Z5wn6zDqRX
	for <incoming@patchwork.ozlabs.org>;
	Sun,  8 Dec 2019 03:47:38 +1100 (AEDT)
X-Original-To: patchwork@lists.ozlabs.org
Delivered-To: patchwork@lists.ozlabs.org
Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized)
	smtp.mailfrom=gmail.com (client-ip=2a00:1450:4864:20::329;
	helo=mail-wm1-x329.google.com; envelope-from=metepolat2000@gmail.com;
	receiver=<UNKNOWN>)
Authentication-Results: lists.ozlabs.org;
	dmarc=pass (p=none dis=none) header.from=gmail.com
Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key;
	unprotected) header.d=gmail.com header.i=@gmail.com
	header.b="C3BNcfDo"; dkim-atps=neutral
Received: from mail-wm1-x329.google.com (mail-wm1-x329.google.com
	[IPv6:2a00:1450:4864:20::329])
	(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
	key-exchange X25519 server-signature RSA-PSS (2048 bits)
	server-digest SHA256) (No client certificate requested)
	by lists.ozlabs.org (Postfix) with ESMTPS id 47Vb315B5hzDqYL
	for <patchwork@lists.ozlabs.org>;
	Sun,  8 Dec 2019 03:47:09 +1100 (AEDT)
Received: by mail-wm1-x329.google.com with SMTP id p9so11049435wmc.2
	for <patchwork@lists.ozlabs.org>;
	Sat, 07 Dec 2019 08:47:09 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025;
	h=from:to:cc:subject:date:message-id:in-reply-to:references
	:mime-version:content-transfer-encoding;
	bh=nD555JZSGfxTAPQpQkFlnB6j5Co0QbfYtzM8m8MV6Pk=;
	b=C3BNcfDo203mSKbQMH/5sEsa24I6IRx6mYjJdPC2mm6Y5TapRwOXngRFOdQkxYaHLt
	ehOjxa0NFjYQYV8eKwwbr0wrm+MY5jl/kH2MLcdNxXQbtAnuj7pGncakbS1xBVmwZnO/
	M9uz+hofY8mTWnd86ipgTaV4KZjY3FxtilMaMVrtpoN71lATbAojwDufWy5f+16dkiOe
	oYZj69PR5BIu7XiK6C5kTU5X4EusRdyMKTBExPohb3l6IT5w7lREumJRzqCHsk5CB5rh
	kqGm3D04A1Q/0hvk171OqgKgd9qPjV6yDh3nghIa+ATudWyLi6G33DSJRRuMqfvkwl5X
	5r+w==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
	d=1e100.net; s=20161025;
	h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to
	:references:mime-version:content-transfer-encoding;
	bh=nD555JZSGfxTAPQpQkFlnB6j5Co0QbfYtzM8m8MV6Pk=;
	b=bUDBLoNsH3GJtjKfC5x9kK1kSjrSaU17Q2oLRY4fqLD0iJVsEQjDfzeywzO/phXQiz
	lohVN3V2bnz6RVYPN8S7dLYKFJFSzqmgVDiwbLBJsMA67n1LoGzjwVHoOrbNFL2M5Pxl
	eN3C1bXgR3wxAlH3yJq28suLkSW2F2wmmshw8hKJUHRUY08JK8RtILiYcKdhFN/c4tOe
	n5WmAE41TV+dpG5B7QZhAWk2g6dDCCGAFP5G7GUrdTV3RlKVfMwAsC4gTsQzTroHOiHR
	esK0aBdxapxaUiWvlmJ9yXfogcOVFG0YJQ63E1ozq/n0r4qikjonbaAu+grenm+xy7Re
	zTDQ==
X-Gm-Message-State: APjAAAXc3T6DQpU6nWUz8jgSOHYKyDA7cAqfvYBY+A9pFUmY3repFC2w
	q/3bniVfNlGVoo5v/8GDZvws5m9G/io=
X-Google-Smtp-Source: 
 APXvYqyLBaoL5voNK9dkZuwIF9yL2KYya7o+0s37sj8D5m20aCz7fHdeZrMO6qi5NUVENasf15+5Lg==
X-Received: by 2002:a1c:731a:: with SMTP id
	d26mr15480461wmb.130.1575737224107;
	Sat, 07 Dec 2019 08:47:04 -0800 (PST)
Received: from Metes-MBP.fritz.box
	(aftr-62-216-202-157.dynamic.mnet-online.de. [62.216.202.157])
	by smtp.gmail.com with ESMTPSA id
	u22sm22083886wru.30.2019.12.07.08.47.03
	(version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);
	Sat, 07 Dec 2019 08:47:03 -0800 (PST)
From: Mete Polat <metepolat2000@gmail.com>
To: patchwork@lists.ozlabs.org
Subject: [PATCH 2/4] models, templates: Add submission relations
Date: Sat,  7 Dec 2019 17:46:19 +0100
Message-Id: <20191207164621.24234-3-metepolat2000@gmail.com>
X-Mailer: git-send-email 2.24.0
In-Reply-To: <20191207164621.24234-1-metepolat2000@gmail.com>
References: <20191207164621.24234-1-metepolat2000@gmail.com>
MIME-Version: 1.0
X-BeenThere: patchwork@lists.ozlabs.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Patchwork development <patchwork.lists.ozlabs.org>
List-Unsubscribe: <https://lists.ozlabs.org/options/patchwork>,
	<mailto:patchwork-request@lists.ozlabs.org?subject=unsubscribe>
List-Archive: <http://lists.ozlabs.org/pipermail/patchwork/>
List-Post: <mailto:patchwork@lists.ozlabs.org>
List-Help: <mailto:patchwork-request@lists.ozlabs.org?subject=help>
List-Subscribe: <https://lists.ozlabs.org/listinfo/patchwork>,
	<mailto:patchwork-request@lists.ozlabs.org?subject=subscribe>
Cc: ralf.ramsauer@oth-regensburg.de
Errors-To: patchwork-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org
Sender: "Patchwork"
	<patchwork-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org>

Introduces the ability to add relations between submissions. Relations
are displayed in the details page of a submission under 'Related'.
Related submissions located in another projects can be viewed as well.

Signed-off-by: Mete Polat <metepolat2000@gmail.com>
---
 .../migrations/0038_submission_relations.py   | 30 +++++++++++++++
 patchwork/models.py                           | 10 +++++
 patchwork/templates/patchwork/submission.html | 37 +++++++++++++++++++
 patchwork/views/patch.py                      |  7 ++++
 4 files changed, 84 insertions(+)
 create mode 100644 patchwork/migrations/0038_submission_relations.py

diff --git a/patchwork/migrations/0038_submission_relations.py b/patchwork/migrations/0038_submission_relations.py
new file mode 100644
index 000000000000..4c5274c64c09
--- /dev/null
+++ b/patchwork/migrations/0038_submission_relations.py
@@ -0,0 +1,30 @@
+# Generated by Django 2.2.6 on 2019-12-08 03:00
+
+import datetime
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+import patchwork.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('patchwork', '0037_event_actor'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='SubmissionRelation',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('by', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL)),
+            ],
+        ),
+        migrations.AddField(
+            model_name='submission',
+            name='related',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='submissions', related_query_name='submission', to='patchwork.SubmissionRelation'),
+        ),
+    ]
diff --git a/patchwork/models.py b/patchwork/models.py
index 7f0efd489ae3..a92203b24ff2 100644
--- a/patchwork/models.py
+++ b/patchwork/models.py
@@ -374,6 +374,9 @@ class Submission(FilenameMixin, EmailMixin, models.Model):
     # submission metadata
 
     name = models.CharField(max_length=255)
+    related = models.ForeignKey(
+        'SubmissionRelation', null=True, blank=True, on_delete=models.SET_NULL,
+        related_name='submissions', related_query_name='submission')
 
     @property
     def list_archive_url(self):
@@ -863,6 +866,13 @@ class BundlePatch(models.Model):
         ordering = ['order']
 
 
+class SubmissionRelation(models.Model):
+    by = models.ForeignKey(User, on_delete=models.CASCADE)
+
+    def __str__(self):
+        return ', '.join(s.name for s in self.submissions.all()) or '<Empty>'
+
+
 @python_2_unicode_compatible
 class Check(models.Model):
 
diff --git a/patchwork/templates/patchwork/submission.html b/patchwork/templates/patchwork/submission.html
index 77a2711ab5b4..bb0391f98ff4 100644
--- a/patchwork/templates/patchwork/submission.html
+++ b/patchwork/templates/patchwork/submission.html
@@ -110,6 +110,43 @@ function toggle_div(link_id, headers_id, label_show, label_hide)
   </td>
  </tr>
 {% endif %}
+{% if submission.related %}
+ <tr>
+  <th>Related</th>
+  <td>
+   <a id="togglerelated"
+      href="javascript:toggle_div('togglerelated', 'related')"
+   >show</a>
+   <div id="related" class="submissionlist" style="display:none;">
+    <ul>
+     {% for sibling in submission.related.submissions.all %}
+      <li>
+       {% if sibling.id != submission.id and sibling.project_id == project.id %}
+        <a href="{% url 'patch-detail' project_id=project.linkname msgid=sibling.url_msgid %}">
+         {{ sibling.name|default:"[no subject]"|truncatechars:100 }}
+        </a>
+       {% endif %}
+      </li>
+     {% endfor %}
+     {% if related_outside %}
+      <a id="togglerelatedoutside"
+         href="javascript:toggle_div('togglerelatedoutside', 'relatedoutside', 'show from other projects')"
+      >show from other projects</a>
+      <div id="relatedoutside" class="submissionlist" style="display:none;">
+       {% for sibling in related_outside %}
+        <li>
+         <a href="{% url 'patch-detail' project_id=sibling.project.linkname msgid=sibling.url_msgid %}">
+          {{ sibling.name|default:"[no subject]"|truncatechars:100 }}
+         </a> (in {{ sibling.project }})
+        </li>
+       {% endfor %}
+      </div>
+     {% endif %}
+    </ul>
+   </div>
+  </td>
+ </tr>
+{% endif %}
 </table>
 
 <div class="patchforms">
diff --git a/patchwork/views/patch.py b/patchwork/views/patch.py
index f34053ce57da..0480614614ad 100644
--- a/patchwork/views/patch.py
+++ b/patchwork/views/patch.py
@@ -110,12 +110,19 @@ def patch_detail(request, project_id, msgid):
     comments = comments.only('submitter', 'date', 'id', 'content',
                              'submission')
 
+    if patch.related:
+        related_outside = patch.related.submissions \
+            .exclude(project=patch.project)
+    else:
+        related_outside = []
+
     context['comments'] = comments
     context['checks'] = patch.check_set.all().select_related('user')
     context['submission'] = patch
     context['patchform'] = form
     context['createbundleform'] = createbundleform
     context['project'] = patch.project
+    context['related_outside'] = related_outside
 
     return render(request, 'patchwork/submission.html', context)
 

From patchwork Sat Dec  7 16:46:20 2019
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
X-Patchwork-Submitter: Mete Polat <metepolat2000@gmail.com>
X-Patchwork-Id: 1205486
Return-Path: 
 <patchwork-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org>
X-Original-To: incoming@patchwork.ozlabs.org
Delivered-To: patchwork-incoming@bilbo.ozlabs.org
Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2])
	(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
	key-exchange X25519 server-signature RSA-PSS (4096 bits)
	server-digest SHA256) (No client certificate requested)
	by ozlabs.org (Postfix) with ESMTPS id 47Vb3H1cp8z9sPL
	for <incoming@patchwork.ozlabs.org>;
	Sun,  8 Dec 2019 03:47:23 +1100 (AEDT)
Authentication-Results: ozlabs.org;
	dmarc=fail (p=none dis=none) header.from=gmail.com
Authentication-Results: ozlabs.org;
	dkim=fail reason="signature verification failed" (2048-bit key;
	unprotected) header.d=gmail.com header.i=@gmail.com
	header.b="W3tUFVkP"; dkim-atps=neutral
Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3])
	by lists.ozlabs.org (Postfix) with ESMTP id 47Vb3D73LqzDqZP
	for <incoming@patchwork.ozlabs.org>;
	Sun,  8 Dec 2019 03:47:20 +1100 (AEDT)
X-Original-To: patchwork@lists.ozlabs.org
Delivered-To: patchwork@lists.ozlabs.org
Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized)
	smtp.mailfrom=gmail.com (client-ip=2a00:1450:4864:20::441;
	helo=mail-wr1-x441.google.com; envelope-from=metepolat2000@gmail.com;
	receiver=<UNKNOWN>)
Authentication-Results: lists.ozlabs.org;
	dmarc=pass (p=none dis=none) header.from=gmail.com
Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key;
	unprotected) header.d=gmail.com header.i=@gmail.com
	header.b="W3tUFVkP"; dkim-atps=neutral
Received: from mail-wr1-x441.google.com (mail-wr1-x441.google.com
	[IPv6:2a00:1450:4864:20::441])
	(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
	key-exchange X25519 server-signature RSA-PSS (2048 bits)
	server-digest SHA256) (No client certificate requested)
	by lists.ozlabs.org (Postfix) with ESMTPS id 47Vb315HgrzDqYP
	for <patchwork@lists.ozlabs.org>;
	Sun,  8 Dec 2019 03:47:09 +1100 (AEDT)
Received: by mail-wr1-x441.google.com with SMTP id t2so11257829wrr.1
	for <patchwork@lists.ozlabs.org>;
	Sat, 07 Dec 2019 08:47:09 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025;
	h=from:to:cc:subject:date:message-id:in-reply-to:references
	:mime-version:content-transfer-encoding;
	bh=fgvIjyEJxcmEZN1pkLQppLKLdt6aShmPCv8LGPTcZao=;
	b=W3tUFVkPI1Q4alWj7qBcMehkwzTeTb8f0BRUVXaHr5OSEhj5gmgIgEGJKVYZcBtskw
	bbLN1Kvdg2eo6Qb0yLg1F/CNRozBbv1cdoq1CJPjgDSqp+3u+02ajRMrSydxVKjzA3sf
	hONovb7JGxwHNP/aj3WwrnkZJtJOt8TRjk+c8fYBiSiMb2GuWBLf0x8Vub3NPzLoHRlk
	3YBinC5au5U8P/548y6FTsjzDIohmmx4Rx808d/R/g2pTV/b0hOVQmnGXzYA1HUp90nc
	46+oMI8oeFII7RiE01yuVcLpEVN3zgMquBcJ/puXoLC/Daf5IA4tyD2eDu7blck0hhIU
	4/XQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
	d=1e100.net; s=20161025;
	h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to
	:references:mime-version:content-transfer-encoding;
	bh=fgvIjyEJxcmEZN1pkLQppLKLdt6aShmPCv8LGPTcZao=;
	b=jfA6wE0xcv5RADwIjLx/qbcBfei5AhfLXj9WgWUbLlr2GYnCbG9Jhnp+GpeZf7Cpzq
	aCbTlPw9Zm2sghvLZ8Lvt1hhAk459Njx9wXsD4lvgNx08zZ0ibDjyuK4k38zXqrHIAZq
	9ZGat1tv+QT/hX85IjCBlb54GYBJt1HxbqM2mpFUv87/vwMSbsFq9g+aRkg4nVrD7pgM
	qM18zlWePuXfo2V9gU7flKIjwYglPZpF2LT3EhEgvCNL5q9lLWawwgk7r2zdwTmxn4lV
	MQ1phGqzY1kCbk2HQtPoqNR+7hZ/SuWxPNtkmRye6t1GCu6qOaACpL6mcAUl07bz7XY7
	0yaQ==
X-Gm-Message-State: APjAAAX1/Advb8aMKVJPYgfDC1Wu7itzrSYg1PS1A5m3GnmRr4lrCaLx
	PzWQH26p3aS03Y3YDHnwbzndTZh5UYM=
X-Google-Smtp-Source: 
 APXvYqwx74C2A6jMwddyTe5RuCy512QGbagfTLLSP52BTHSP8LtAc5GFwGm2uJCgYtclPYtlSUAyOw==
X-Received: by 2002:adf:f2d0:: with SMTP id
	d16mr20813380wrp.110.1575737225354;
	Sat, 07 Dec 2019 08:47:05 -0800 (PST)
Received: from Metes-MBP.fritz.box
	(aftr-62-216-202-157.dynamic.mnet-online.de. [62.216.202.157])
	by smtp.gmail.com with ESMTPSA id
	u22sm22083886wru.30.2019.12.07.08.47.04
	(version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);
	Sat, 07 Dec 2019 08:47:04 -0800 (PST)
From: Mete Polat <metepolat2000@gmail.com>
To: patchwork@lists.ozlabs.org
Subject: [PATCH 3/4] docs: Add missing series index schema
Date: Sat,  7 Dec 2019 17:46:20 +0100
Message-Id: <20191207164621.24234-4-metepolat2000@gmail.com>
X-Mailer: git-send-email 2.24.0
In-Reply-To: <20191207164621.24234-1-metepolat2000@gmail.com>
References: <20191207164621.24234-1-metepolat2000@gmail.com>
MIME-Version: 1.0
X-BeenThere: patchwork@lists.ozlabs.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Patchwork development <patchwork.lists.ozlabs.org>
List-Unsubscribe: <https://lists.ozlabs.org/options/patchwork>,
	<mailto:patchwork-request@lists.ozlabs.org?subject=unsubscribe>
List-Archive: <http://lists.ozlabs.org/pipermail/patchwork/>
List-Post: <mailto:patchwork@lists.ozlabs.org>
List-Help: <mailto:patchwork-request@lists.ozlabs.org?subject=help>
List-Subscribe: <https://lists.ozlabs.org/listinfo/patchwork>,
	<mailto:patchwork-request@lists.ozlabs.org?subject=subscribe>
Cc: ralf.ramsauer@oth-regensburg.de
Errors-To: patchwork-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org
Sender: "Patchwork"
	<patchwork-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org>

Fixes: 7d8e24bc84bd ("docs: Start documenting API using OpenAPI")
Signed-off-by: Mete Polat <metepolat2000@gmail.com>
Reviewed-by: Stephen Finucane <stephen@that.guru>
---
 docs/api/schemas/latest/patchwork.yaml | 5 +++++
 docs/api/schemas/patchwork.j2          | 5 +++++
 docs/api/schemas/v1.0/patchwork.yaml   | 5 +++++
 docs/api/schemas/v1.1/patchwork.yaml   | 5 +++++
 docs/api/schemas/v1.2/patchwork.yaml   | 5 +++++
 5 files changed, 25 insertions(+)

diff --git a/docs/api/schemas/latest/patchwork.yaml b/docs/api/schemas/latest/patchwork.yaml
index fc23cdb03078..a5e235be936d 100644
--- a/docs/api/schemas/latest/patchwork.yaml
+++ b/docs/api/schemas/latest/patchwork.yaml
@@ -1353,6 +1353,11 @@ components:
           type: string
           format: uri
           readOnly: true
+        series:
+          title: Series URL
+          type: string
+          format: uri
+          readOnly: true
     Bundle:
       required:
         - name
diff --git a/docs/api/schemas/patchwork.j2 b/docs/api/schemas/patchwork.j2
index 85f3977ca15c..196d78466b55 100644
--- a/docs/api/schemas/patchwork.j2
+++ b/docs/api/schemas/patchwork.j2
@@ -1364,6 +1364,11 @@ components:
           type: string
           format: uri
           readOnly: true
+        series:
+          title: Series URL
+          type: string
+          format: uri
+          readOnly: true
     Bundle:
       required:
         - name
diff --git a/docs/api/schemas/v1.0/patchwork.yaml b/docs/api/schemas/v1.0/patchwork.yaml
index b01cbcfa904a..6c7c068aeb76 100644
--- a/docs/api/schemas/v1.0/patchwork.yaml
+++ b/docs/api/schemas/v1.0/patchwork.yaml
@@ -1218,6 +1218,11 @@ components:
           type: string
           format: uri
           readOnly: true
+        series:
+          title: Series URL
+          type: string
+          format: uri
+          readOnly: true
     Bundle:
       required:
         - name
diff --git a/docs/api/schemas/v1.1/patchwork.yaml b/docs/api/schemas/v1.1/patchwork.yaml
index f85c8711cb56..babc972ace35 100644
--- a/docs/api/schemas/v1.1/patchwork.yaml
+++ b/docs/api/schemas/v1.1/patchwork.yaml
@@ -1218,6 +1218,11 @@ components:
           type: string
           format: uri
           readOnly: true
+        series:
+          title: Series URL
+          type: string
+          format: uri
+          readOnly: true
     Bundle:
       required:
         - name
diff --git a/docs/api/schemas/v1.2/patchwork.yaml b/docs/api/schemas/v1.2/patchwork.yaml
index b4d1cf689009..d7b4d2957cff 100644
--- a/docs/api/schemas/v1.2/patchwork.yaml
+++ b/docs/api/schemas/v1.2/patchwork.yaml
@@ -1353,6 +1353,11 @@ components:
           type: string
           format: uri
           readOnly: true
+        series:
+          title: Series URL
+          type: string
+          format: uri
+          readOnly: true
     Bundle:
       required:
         - name

From patchwork Sat Dec  7 16:46:21 2019
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
X-Patchwork-Submitter: Mete Polat <metepolat2000@gmail.com>
X-Patchwork-Id: 1205490
Return-Path: 
 <patchwork-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org>
X-Original-To: incoming@patchwork.ozlabs.org
Delivered-To: patchwork-incoming@bilbo.ozlabs.org
Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2])
	(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
	key-exchange X25519 server-signature RSA-PSS (4096 bits))
	(No client certificate requested)
	by ozlabs.org (Postfix) with ESMTPS id 47Vb4V4Z9Nz9sPL
	for <incoming@patchwork.ozlabs.org>;
	Sun,  8 Dec 2019 03:48:26 +1100 (AEDT)
Authentication-Results: ozlabs.org;
	dmarc=fail (p=none dis=none) header.from=gmail.com
Authentication-Results: ozlabs.org;
	dkim=fail reason="signature verification failed" (2048-bit key;
	unprotected) header.d=gmail.com header.i=@gmail.com
	header.b="ZR6Ous7Y"; dkim-atps=neutral
Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3])
	by lists.ozlabs.org (Postfix) with ESMTP id 47Vb4V3QgvzDqbC
	for <incoming@patchwork.ozlabs.org>;
	Sun,  8 Dec 2019 03:48:26 +1100 (AEDT)
X-Original-To: patchwork@lists.ozlabs.org
Delivered-To: patchwork@lists.ozlabs.org
Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized)
	smtp.mailfrom=gmail.com (client-ip=2a00:1450:4864:20::333;
	helo=mail-wm1-x333.google.com; envelope-from=metepolat2000@gmail.com;
	receiver=<UNKNOWN>)
Authentication-Results: lists.ozlabs.org;
	dmarc=pass (p=none dis=none) header.from=gmail.com
Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key;
	unprotected) header.d=gmail.com header.i=@gmail.com
	header.b="ZR6Ous7Y"; dkim-atps=neutral
Received: from mail-wm1-x333.google.com (mail-wm1-x333.google.com
	[IPv6:2a00:1450:4864:20::333])
	(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
	key-exchange X25519 server-signature RSA-PSS (2048 bits)
	server-digest SHA256) (No client certificate requested)
	by lists.ozlabs.org (Postfix) with ESMTPS id 47Vb331HMrzDqYK
	for <patchwork@lists.ozlabs.org>;
	Sun,  8 Dec 2019 03:47:10 +1100 (AEDT)
Received: by mail-wm1-x333.google.com with SMTP id f129so10486354wmf.2
	for <patchwork@lists.ozlabs.org>;
	Sat, 07 Dec 2019 08:47:10 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025;
	h=from:to:cc:subject:date:message-id:in-reply-to:references
	:mime-version:content-transfer-encoding;
	bh=5bTi3gk/38jw3cWfOPQDZRCkQhQIdi3mcPOforydq3M=;
	b=ZR6Ous7YrGocrrqh7Jj2yQR6k9YA7Fa/S65jIod3nczub29hiRHWG9JkermFx9iQb1
	W6PIuplVI4gArZ6IQcQDMzJhI8a5wc48GWIdu1qjQxIRgFasfJnP9zMq/nY6CbOww5aS
	1qmt1iEHfFjFrbQAgyHukmyJ3CrAUGD8AhQYyQLZwGdpSftgmYpozVryQSpjNOmN+hMS
	0ukmY7+Aq7DdQiw0MD+/U+Q2Eff8r6Jl50XfvdP5PWfkfxikp/lxiRR4qEmAs3iIEtLP
	t6y26tbPHK/iJ6aSJC4y4c7LjARn3UvbgzWJC1wEBviBK/Ejtd+WxKkoa31IWqBD4FzB
	nkbA==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
	d=1e100.net; s=20161025;
	h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to
	:references:mime-version:content-transfer-encoding;
	bh=5bTi3gk/38jw3cWfOPQDZRCkQhQIdi3mcPOforydq3M=;
	b=pTDVLh2s6Fmuso8uDdsnSj+DL2mLSAd/xITB7BTyDdj5qGN7TVWjKbYxzPCr6LpKDj
	Ewliwo8lVKuMuP/EMMgSe/DzVf4z1sx0hna3zUj0ZTe6bQ35rWkn6Qwgs6yI+EqIGTy0
	Hp1ayy/O2m1WTYg4MrrF6B88ivZKRmMdiDQkK/tYdwXN4QMEwDNXbu285ynP9LzIYMyB
	GQOrIawIuenKHWgIcij+1ObLAyjw8IKBqLsZMs+8M4flg35m06saQcTx4+Z6zrgfe7hj
	zCX6oiLkeynm0imxSy4eRTbtz8SnrEKbsjGOyoLPz5zFBDZswr1VawvcIH2C1h1WUMjU
	bShg==
X-Gm-Message-State: APjAAAWt3nzrbg+JntTyYhDiS2IRc0IVB9iQ4qsQ3ly3dwGWGoGIezE/
	1Zm6sZ+zQRsHpPLdbMsQ+Pl/6S4KthL0Qg==
X-Google-Smtp-Source: 
 APXvYqwuseHdir6AASbKXK2W9uHS4lXvvr32qlj5Z68N8OLLrWt1caQHrZj11Sr4rqxPCqt/Hq1m1A==
X-Received: by 2002:a05:600c:2947:: with SMTP id
	n7mr15247304wmd.156.1575737226709;
	Sat, 07 Dec 2019 08:47:06 -0800 (PST)
Received: from Metes-MBP.fritz.box
	(aftr-62-216-202-157.dynamic.mnet-online.de. [62.216.202.157])
	by smtp.gmail.com with ESMTPSA id
	u22sm22083886wru.30.2019.12.07.08.47.05
	(version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);
	Sat, 07 Dec 2019 08:47:06 -0800 (PST)
From: Mete Polat <metepolat2000@gmail.com>
To: patchwork@lists.ozlabs.org
Subject: [PATCH 4/4]  REST: Add submission relations
Date: Sat,  7 Dec 2019 17:46:21 +0100
Message-Id: <20191207164621.24234-5-metepolat2000@gmail.com>
X-Mailer: git-send-email 2.24.0
In-Reply-To: <20191207164621.24234-1-metepolat2000@gmail.com>
References: <20191207164621.24234-1-metepolat2000@gmail.com>
MIME-Version: 1.0
X-BeenThere: patchwork@lists.ozlabs.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Patchwork development <patchwork.lists.ozlabs.org>
List-Unsubscribe: <https://lists.ozlabs.org/options/patchwork>,
	<mailto:patchwork-request@lists.ozlabs.org?subject=unsubscribe>
List-Archive: <http://lists.ozlabs.org/pipermail/patchwork/>
List-Post: <mailto:patchwork@lists.ozlabs.org>
List-Help: <mailto:patchwork-request@lists.ozlabs.org?subject=help>
List-Subscribe: <https://lists.ozlabs.org/listinfo/patchwork>,
	<mailto:patchwork-request@lists.ozlabs.org?subject=subscribe>
Cc: ralf.ramsauer@oth-regensburg.de
Errors-To: patchwork-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org
Sender: "Patchwork"
	<patchwork-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org>

View relations and add/update/delete them as a maintainer. Maintainers
can only create relations of submissions (patches/cover letters) which
are part of a project they maintain.

New REST API urls:
api/relations/
api/relations/<relation_id>/

Co-authored-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Mete Polat <metepolat2000@gmail.com>
---
Optimize db queries:
  I have spent quite a lot of time in optimizing the db queries for the REST API
  (thanks for the tip with the Django toolbar). Daniel stated that
  prefetch_related is possibly hitting the database for every relation when
  prefetching submissions but it turns out that we can tell Django to use a
  statement like:
      SELECT *
      FROM `patchwork_patch`
     INNER JOIN `patchwork_submission`
        ON (`patchwork_patch`.`submission_ptr_id` = `patchwork_submission`.`id`)
     WHERE `patchwork_patch`.`submission_ptr_id` IN (LIST_OF_ALL_SUBMISSION_IDS)

   We do the same for `patchwork_coverletter`.
   This means we only hit the db two times for casting _all_ submissions to a
   patch or cover-letter.

   Prefetching submissions__project eliminates similar and duplicate queries
   that are used to determine whether a logged in user is at least maintainer
   of one submission's project.

 docs/api/schemas/latest/patchwork.yaml        | 273 +++++++++++++++++
 docs/api/schemas/patchwork.j2                 | 285 ++++++++++++++++++
 docs/api/schemas/v1.2/patchwork.yaml          | 273 +++++++++++++++++
 patchwork/api/embedded.py                     |  39 +++
 patchwork/api/index.py                        |   1 +
 patchwork/api/relation.py                     | 121 ++++++++
 patchwork/models.py                           |   6 +
 patchwork/tests/api/test_relation.py          | 181 +++++++++++
 patchwork/tests/utils.py                      |  15 +
 patchwork/urls.py                             |  11 +
 ...submission-relations-c96bb6c567b416d8.yaml |  10 +
 11 files changed, 1215 insertions(+)
 create mode 100644 patchwork/api/relation.py
 create mode 100644 patchwork/tests/api/test_relation.py
 create mode 100644 releasenotes/notes/add-submission-relations-c96bb6c567b416d8.yaml

diff --git a/docs/api/schemas/latest/patchwork.yaml b/docs/api/schemas/latest/patchwork.yaml
index a5e235be936d..7dd24fd700d5 100644
--- a/docs/api/schemas/latest/patchwork.yaml
+++ b/docs/api/schemas/latest/patchwork.yaml
@@ -1039,6 +1039,188 @@ paths:
                 $ref: '#/components/schemas/Error'
       tags:
         - series
+  /api/relations/:
+    get:
+      description: List relations.
+      operationId: relations_list
+      parameters:
+        - $ref: '#/components/parameters/Page'
+        - $ref: '#/components/parameters/PageSize'
+        - $ref: '#/components/parameters/Order'
+      responses:
+        '200':
+          description: ''
+          headers:
+            Link:
+              $ref: '#/components/headers/Link'
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: '#/components/schemas/Relation'
+      tags:
+        - relations
+    post:
+      description: Create a relation.
+      operationId: relations_create
+      security:
+        - basicAuth: []
+        - apiKeyAuth: []
+      requestBody:
+        $ref: '#/components/requestBodies/Relation'
+      responses:
+        '201':
+          description: ''
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Relation'
+        '400':
+          description: Invalid Request
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '403':
+          description: Forbidden
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '404':
+          description: Not found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '409':
+          description: Conflict
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+      tags:
+        - checks
+  /api/relations/{id}/:
+    get:
+      description: Show a relation.
+      operationId: relation_read
+      parameters:
+        - in: path
+          name: id
+          description: A unique integer value identifying this relation.
+          required: true
+          schema:
+            title: ID
+            type: integer
+      responses:
+        '200':
+          description: ''
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Relation'
+        '404':
+          description: Not found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '409':
+          description: Conflict
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+      tags:
+        - relations
+    patch:
+      description: Update a relation (partial).
+      operationId: relations_partial_update
+      security:
+        - basicAuth: []
+        - apiKeyAuth: []
+      parameters:
+        - in: path
+          name: id
+          description: A unique integer value identifying this relation.
+          required: true
+          schema:
+            title: ID
+            type: integer
+      requestBody:
+        $ref: '#/components/requestBodies/Relation'
+      responses:
+        '200':
+          description: ''
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Relation'
+        '400':
+          description: Bad request
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '403':
+          description: Forbidden
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '404':
+          description: Not found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+      tags:
+        - relations
+    put:
+      description: Update a relation.
+      operationId: relations_update
+      security:
+        - basicAuth: []
+        - apiKeyAuth: []
+      parameters:
+        - in: path
+          name: id
+          description: A unique integer value identifying this relation.
+          required: true
+          schema:
+            title: ID
+            type: integer
+      requestBody:
+        $ref: '#/components/requestBodies/Relation'
+      responses:
+        '200':
+          description: ''
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Relation'
+        '400':
+          description: Bad request
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '403':
+          description: Forbidden
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '404':
+          description: Not found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+      tags:
+        - relations
   /api/users/:
     get:
       description: List users.
@@ -1314,6 +1496,18 @@ components:
         application/x-www-form-urlencoded:
           schema:
             $ref: '#/components/schemas/User'
+    Relation:
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/RelationUpdate'
+        multipart/form-data:
+          schema:
+            $ref: '#/components/schemas/RelationUpdate'
+        application/x-www-form-urlencoded:
+          schema:
+            $ref: '#/components/schemas/RelationUpdate'
   schemas:
     Index:
       type: object
@@ -1358,6 +1552,11 @@ components:
           type: string
           format: uri
           readOnly: true
+        relations:
+          title: Relations URL
+          type: string
+          format: uri
+          readOnly: true
     Bundle:
       required:
         - name
@@ -1943,6 +2142,14 @@ components:
           title: Delegate
           type: integer
           nullable: true
+    RelationUpdate:
+      type: object
+      properties:
+        submissions:
+          title: Submission IDs
+          type: array
+          items:
+            type: integer
     Person:
       type: object
       properties:
@@ -2133,6 +2340,30 @@ components:
             $ref: '#/components/schemas/PatchEmbedded'
           readOnly: true
           uniqueItems: true
+    Relation:
+      type: object
+      properties:
+        id:
+          title: ID
+          type: integer
+        url:
+          title: URL
+          type: string
+          format: uri
+          readOnly: true
+        by:
+          type: object
+          title: By
+          readOnly: true
+          allOf:
+            - $ref: '#/components/schemas/UserEmbedded'
+        submissions:
+          title: Submissions
+          type: array
+          items:
+            $ref: '#/components/schemas/SubmissionEmbedded'
+          readOnly: true
+          uniqueItems: true
     User:
       type: object
       properties:
@@ -2211,6 +2442,48 @@ components:
           maxLength: 255
           minLength: 1
           readOnly: true
+    SubmissionEmbedded:
+      type: object
+      properties:
+        id:
+          title: ID
+          type: integer
+          readOnly: true
+        url:
+          title: URL
+          type: string
+          format: uri
+          readOnly: true
+        web_url:
+          title: Web URL
+          type: string
+          format: uri
+          readOnly: true
+        msgid:
+          title: Message ID
+          type: string
+          readOnly: true
+          minLength: 1
+        list_archive_url:
+          title: List archive URL
+          type: string
+          readOnly: true
+          nullable: true
+        date:
+          title: Date
+          type: string
+          format: iso8601
+          readOnly: true
+        name:
+          title: Name
+          type: string
+          readOnly: true
+          minLength: 1
+        mbox:
+          title: Mbox
+          type: string
+          format: uri
+          readOnly: true
     CoverLetterEmbedded:
       type: object
       properties:
diff --git a/docs/api/schemas/patchwork.j2 b/docs/api/schemas/patchwork.j2
index 196d78466b55..a034029accf9 100644
--- a/docs/api/schemas/patchwork.j2
+++ b/docs/api/schemas/patchwork.j2
@@ -1048,6 +1048,190 @@ paths:
                 $ref: '#/components/schemas/Error'
       tags:
         - series
+{% if version >= (1, 2) %}
+  /api/{{ version_url }}relations/:
+    get:
+      description: List relations.
+      operationId: relations_list
+      parameters:
+        - $ref: '#/components/parameters/Page'
+        - $ref: '#/components/parameters/PageSize'
+        - $ref: '#/components/parameters/Order'
+      responses:
+        '200':
+          description: ''
+          headers:
+            Link:
+              $ref: '#/components/headers/Link'
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: '#/components/schemas/Relation'
+      tags:
+        - relations
+    post:
+      description: Create a relation.
+      operationId: relations_create
+      security:
+        - basicAuth: []
+        - apiKeyAuth: []
+      requestBody:
+        $ref: '#/components/requestBodies/Relation'
+      responses:
+        '201':
+          description: ''
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Relation'
+        '400':
+          description: Invalid Request
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '403':
+          description: Forbidden
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '404':
+          description: Not found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '409':
+          description: Conflict
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+      tags:
+        - checks
+  /api/{{ version_url }}relations/{id}/:
+    get:
+      description: Show a relation.
+      operationId: relation_read
+      parameters:
+        - in: path
+          name: id
+          description: A unique integer value identifying this relation.
+          required: true
+          schema:
+            title: ID
+            type: integer
+      responses:
+        '200':
+          description: ''
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Relation'
+        '404':
+          description: Not found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '409':
+          description: Conflict
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+      tags:
+        - relations
+    patch:
+      description: Update a relation (partial).
+      operationId: relations_partial_update
+      security:
+        - basicAuth: []
+        - apiKeyAuth: []
+      parameters:
+        - in: path
+          name: id
+          description: A unique integer value identifying this relation.
+          required: true
+          schema:
+            title: ID
+            type: integer
+      requestBody:
+        $ref: '#/components/requestBodies/Relation'
+      responses:
+        '200':
+          description: ''
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Relation'
+        '400':
+          description: Bad request
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '403':
+          description: Forbidden
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '404':
+          description: Not found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+      tags:
+        - relations
+    put:
+      description: Update a relation.
+      operationId: relations_update
+      security:
+        - basicAuth: []
+        - apiKeyAuth: []
+      parameters:
+        - in: path
+          name: id
+          description: A unique integer value identifying this relation.
+          required: true
+          schema:
+            title: ID
+            type: integer
+      requestBody:
+        $ref: '#/components/requestBodies/Relation'
+      responses:
+        '200':
+          description: ''
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Relation'
+        '400':
+          description: Bad request
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '403':
+          description: Forbidden
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '404':
+          description: Not found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+      tags:
+        - relations
+{% endif %}
   /api/{{ version_url }}users/:
     get:
       description: List users.
@@ -1325,6 +1509,20 @@ components:
         application/x-www-form-urlencoded:
           schema:
             $ref: '#/components/schemas/User'
+{% if version >= (1, 2) %}
+    Relation:
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/RelationUpdate'
+        multipart/form-data:
+          schema:
+            $ref: '#/components/schemas/RelationUpdate'
+        application/x-www-form-urlencoded:
+          schema:
+            $ref: '#/components/schemas/RelationUpdate'
+{% endif %}
   schemas:
     Index:
       type: object
@@ -1369,6 +1567,13 @@ components:
           type: string
           format: uri
           readOnly: true
+{% if version >= (1, 2) %}
+        relations:
+          title: Relations URL
+          type: string
+          format: uri
+          readOnly: true
+{% endif %}
     Bundle:
       required:
         - name
@@ -1981,6 +2186,16 @@ components:
           title: Delegate
           type: integer
           nullable: true
+{% if version >= (1, 2) %}
+    RelationUpdate:
+      type: object
+      properties:
+        submissions:
+          title: Submission IDs
+          type: array
+          items:
+            type: integer
+{% endif %}
     Person:
       type: object
       properties:
@@ -2177,6 +2392,32 @@ components:
             $ref: '#/components/schemas/PatchEmbedded'
           readOnly: true
           uniqueItems: true
+{% if version >= (1, 2) %}
+    Relation:
+      type: object
+      properties:
+        id:
+          title: ID
+          type: integer
+        url:
+          title: URL
+          type: string
+          format: uri
+          readOnly: true
+        by:
+          type: object
+          title: By
+          readOnly: true
+          allOf:
+            - $ref: '#/components/schemas/UserEmbedded'
+        submissions:
+          title: Submissions
+          type: array
+          items:
+            $ref: '#/components/schemas/SubmissionEmbedded'
+          readOnly: true
+          uniqueItems: true
+{% endif %}
     User:
       type: object
       properties:
@@ -2255,6 +2496,50 @@ components:
           maxLength: 255
           minLength: 1
           readOnly: true
+{% if version >= (1, 2) %}
+    SubmissionEmbedded:
+      type: object
+      properties:
+        id:
+          title: ID
+          type: integer
+          readOnly: true
+        url:
+          title: URL
+          type: string
+          format: uri
+          readOnly: true
+        web_url:
+          title: Web URL
+          type: string
+          format: uri
+          readOnly: true
+        msgid:
+          title: Message ID
+          type: string
+          readOnly: true
+          minLength: 1
+        list_archive_url:
+          title: List archive URL
+          type: string
+          readOnly: true
+          nullable: true
+        date:
+          title: Date
+          type: string
+          format: iso8601
+          readOnly: true
+        name:
+          title: Name
+          type: string
+          readOnly: true
+          minLength: 1
+        mbox:
+          title: Mbox
+          type: string
+          format: uri
+          readOnly: true
+{% endif %}
     CoverLetterEmbedded:
       type: object
       properties:
diff --git a/docs/api/schemas/v1.2/patchwork.yaml b/docs/api/schemas/v1.2/patchwork.yaml
index d7b4d2957cff..99425e968881 100644
--- a/docs/api/schemas/v1.2/patchwork.yaml
+++ b/docs/api/schemas/v1.2/patchwork.yaml
@@ -1039,6 +1039,188 @@ paths:
                 $ref: '#/components/schemas/Error'
       tags:
         - series
+  /api/1.2/relations/:
+    get:
+      description: List relations.
+      operationId: relations_list
+      parameters:
+        - $ref: '#/components/parameters/Page'
+        - $ref: '#/components/parameters/PageSize'
+        - $ref: '#/components/parameters/Order'
+      responses:
+        '200':
+          description: ''
+          headers:
+            Link:
+              $ref: '#/components/headers/Link'
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: '#/components/schemas/Relation'
+      tags:
+        - relations
+    post:
+      description: Create a relation.
+      operationId: relations_create
+      security:
+        - basicAuth: []
+        - apiKeyAuth: []
+      requestBody:
+        $ref: '#/components/requestBodies/Relation'
+      responses:
+        '201':
+          description: ''
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Relation'
+        '400':
+          description: Invalid Request
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '403':
+          description: Forbidden
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '404':
+          description: Not found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '409':
+          description: Conflict
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+      tags:
+        - checks
+  /api/1.2/relations/{id}/:
+    get:
+      description: Show a relation.
+      operationId: relation_read
+      parameters:
+        - in: path
+          name: id
+          description: A unique integer value identifying this relation.
+          required: true
+          schema:
+            title: ID
+            type: integer
+      responses:
+        '200':
+          description: ''
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Relation'
+        '404':
+          description: Not found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '409':
+          description: Conflict
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+      tags:
+        - relations
+    patch:
+      description: Update a relation (partial).
+      operationId: relations_partial_update
+      security:
+        - basicAuth: []
+        - apiKeyAuth: []
+      parameters:
+        - in: path
+          name: id
+          description: A unique integer value identifying this relation.
+          required: true
+          schema:
+            title: ID
+            type: integer
+      requestBody:
+        $ref: '#/components/requestBodies/Relation'
+      responses:
+        '200':
+          description: ''
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Relation'
+        '400':
+          description: Bad request
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '403':
+          description: Forbidden
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '404':
+          description: Not found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+      tags:
+        - relations
+    put:
+      description: Update a relation.
+      operationId: relations_update
+      security:
+        - basicAuth: []
+        - apiKeyAuth: []
+      parameters:
+        - in: path
+          name: id
+          description: A unique integer value identifying this relation.
+          required: true
+          schema:
+            title: ID
+            type: integer
+      requestBody:
+        $ref: '#/components/requestBodies/Relation'
+      responses:
+        '200':
+          description: ''
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Relation'
+        '400':
+          description: Bad request
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '403':
+          description: Forbidden
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+        '404':
+          description: Not found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Error'
+      tags:
+        - relations
   /api/1.2/users/:
     get:
       description: List users.
@@ -1314,6 +1496,18 @@ components:
         application/x-www-form-urlencoded:
           schema:
             $ref: '#/components/schemas/User'
+    Relation:
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/RelationUpdate'
+        multipart/form-data:
+          schema:
+            $ref: '#/components/schemas/RelationUpdate'
+        application/x-www-form-urlencoded:
+          schema:
+            $ref: '#/components/schemas/RelationUpdate'
   schemas:
     Index:
       type: object
@@ -1358,6 +1552,11 @@ components:
           type: string
           format: uri
           readOnly: true
+        relations:
+          title: Relations URL
+          type: string
+          format: uri
+          readOnly: true
     Bundle:
       required:
         - name
@@ -1943,6 +2142,14 @@ components:
           title: Delegate
           type: integer
           nullable: true
+    RelationUpdate:
+      type: object
+      properties:
+        submissions:
+          title: Submission IDs
+          type: array
+          items:
+            type: integer
     Person:
       type: object
       properties:
@@ -2133,6 +2340,30 @@ components:
             $ref: '#/components/schemas/PatchEmbedded'
           readOnly: true
           uniqueItems: true
+    Relation:
+      type: object
+      properties:
+        id:
+          title: ID
+          type: integer
+        url:
+          title: URL
+          type: string
+          format: uri
+          readOnly: true
+        by:
+          type: object
+          title: By
+          readOnly: true
+          allOf:
+            - $ref: '#/components/schemas/UserEmbedded'
+        submissions:
+          title: Submissions
+          type: array
+          items:
+            $ref: '#/components/schemas/SubmissionEmbedded'
+          readOnly: true
+          uniqueItems: true
     User:
       type: object
       properties:
@@ -2211,6 +2442,48 @@ components:
           maxLength: 255
           minLength: 1
           readOnly: true
+    SubmissionEmbedded:
+      type: object
+      properties:
+        id:
+          title: ID
+          type: integer
+          readOnly: true
+        url:
+          title: URL
+          type: string
+          format: uri
+          readOnly: true
+        web_url:
+          title: Web URL
+          type: string
+          format: uri
+          readOnly: true
+        msgid:
+          title: Message ID
+          type: string
+          readOnly: true
+          minLength: 1
+        list_archive_url:
+          title: List archive URL
+          type: string
+          readOnly: true
+          nullable: true
+        date:
+          title: Date
+          type: string
+          format: iso8601
+          readOnly: true
+        name:
+          title: Name
+          type: string
+          readOnly: true
+          minLength: 1
+        mbox:
+          title: Mbox
+          type: string
+          format: uri
+          readOnly: true
     CoverLetterEmbedded:
       type: object
       properties:
diff --git a/patchwork/api/embedded.py b/patchwork/api/embedded.py
index de4f31165ee7..0fba291b62b8 100644
--- a/patchwork/api/embedded.py
+++ b/patchwork/api/embedded.py
@@ -102,6 +102,45 @@ class CheckSerializer(SerializedRelatedField):
             }
 
 
+def _upgrade_instance(instance):
+    if hasattr(instance, 'patch'):
+        return instance.patch
+    else:
+        return instance.coverletter
+
+
+class SubmissionSerializer(SerializedRelatedField):
+
+    class _Serializer(BaseHyperlinkedModelSerializer):
+        """We need to 'upgrade' or specialise the submission to the relevant
+        subclass, so we can't use the mixins. This is gross but can go away
+        once we flatten the models."""
+        url = SerializerMethodField()
+        web_url = SerializerMethodField()
+        mbox = SerializerMethodField()
+
+        def get_url(self, instance):
+            instance = _upgrade_instance(instance)
+            request = self.context.get('request')
+            return request.build_absolute_uri(instance.get_absolute_api_url())
+
+        def get_web_url(self, instance):
+            instance = _upgrade_instance(instance)
+            request = self.context.get('request')
+            return request.build_absolute_uri(instance.get_absolute_url())
+
+        def get_mbox(self, instance):
+            instance = _upgrade_instance(instance)
+            request = self.context.get('request')
+            return request.build_absolute_uri(instance.get_mbox_url())
+
+        class Meta:
+            model = models.Submission
+            fields = ('id', 'url', 'web_url', 'msgid', 'list_archive_url',
+                      'date', 'name', 'mbox')
+            read_only_fields = fields
+
+
 class CoverLetterSerializer(SerializedRelatedField):
 
     class _Serializer(MboxMixin, WebURLMixin, BaseHyperlinkedModelSerializer):
diff --git a/patchwork/api/index.py b/patchwork/api/index.py
index 45485c9106f6..cf1845393835 100644
--- a/patchwork/api/index.py
+++ b/patchwork/api/index.py
@@ -21,4 +21,5 @@ class IndexView(APIView):
             'series': reverse('api-series-list', request=request),
             'events': reverse('api-event-list', request=request),
             'bundles': reverse('api-bundle-list', request=request),
+            'relations': reverse('api-relation-list', request=request),
         })
diff --git a/patchwork/api/relation.py b/patchwork/api/relation.py
new file mode 100644
index 000000000000..37640d62e9cc
--- /dev/null
+++ b/patchwork/api/relation.py
@@ -0,0 +1,121 @@
+# Patchwork - automated patch tracking system
+# Copyright (C) 2019, Bayerische Motoren Werke Aktiengesellschaft (BMW AG)
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+from rest_framework import permissions
+from rest_framework import status
+from rest_framework.exceptions import PermissionDenied, APIException
+from rest_framework.generics import GenericAPIView
+from rest_framework.generics import ListCreateAPIView
+from rest_framework.generics import RetrieveUpdateDestroyAPIView
+from rest_framework.serializers import ModelSerializer
+
+from patchwork.api.base import PatchworkPermission
+from patchwork.api.embedded import SubmissionSerializer
+from patchwork.api.embedded import UserSerializer
+from patchwork.models import SubmissionRelation
+
+
+class MaintainerPermission(PatchworkPermission):
+
+    def has_permission(self, request, view):
+        if request.method in permissions.SAFE_METHODS:
+            return True
+
+        # Prevent showing an HTML POST form in the browseable API for logged in
+        # users who are not maintainers.
+        return len(request.user.maintains) > 0
+
+    def has_object_permission(self, request, view, relation):
+        if request.method in permissions.SAFE_METHODS:
+            return True
+
+        maintains = request.user.maintains
+        submissions = relation.submissions.all()
+        # user has to be maintainer of every project a submission is part of
+        return self.check_user_maintains_all(maintains, submissions)
+
+    @staticmethod
+    def check_user_maintains_all(maintains, submissions):
+        if any(s.project not in maintains for s in submissions):
+            detail = 'At least one submission is part of a project you are ' \
+                     'not maintaining.'
+            raise PermissionDenied(detail=detail)
+        return True
+
+
+class SubmissionConflict(APIException):
+    status_code = status.HTTP_409_CONFLICT
+    default_detail = 'At least one submission is already part of another ' \
+                     'relation. You have to explicitly remove a submission ' \
+                     'from its existing relation before moving it to this one.'
+
+
+class SubmissionRelationSerializer(ModelSerializer):
+    by = UserSerializer(read_only=True)
+    submissions = SubmissionSerializer(many=True)
+
+    def create(self, validated_data):
+        submissions = validated_data['submissions']
+        if any(submission.related_id is not None
+               for submission in submissions):
+            raise SubmissionConflict()
+        return super(SubmissionRelationSerializer, self).create(validated_data)
+
+    def update(self, instance, validated_data):
+        submissions = validated_data['submissions']
+        if any(submission.related_id is not None and
+               submission.related_id != instance.id
+               for submission in submissions):
+            raise SubmissionConflict()
+        return super(SubmissionRelationSerializer, self) \
+            .update(instance, validated_data)
+
+    class Meta:
+        model = SubmissionRelation
+        fields = ('id', 'url', 'by', 'submissions',)
+        read_only_fields = ('url', 'by', )
+        extra_kwargs = {
+            'url': {'view_name': 'api-relation-detail'},
+        }
+
+
+class SubmissionRelationMixin(GenericAPIView):
+    serializer_class = SubmissionRelationSerializer
+    permission_classes = (MaintainerPermission,)
+
+    def initial(self, request, *args, **kwargs):
+        user = request.user
+        if not hasattr(user, 'maintains'):
+            if user.is_authenticated:
+                user.maintains = user.profile.maintainer_projects.all()
+            else:
+                user.maintains = []
+        super(SubmissionRelationMixin, self).initial(request, *args, **kwargs)
+
+    def get_queryset(self):
+        return SubmissionRelation.objects.all() \
+            .select_related('by') \
+            .prefetch_related('submissions__patch',
+                              'submissions__coverletter',
+                              'submissions__project')
+
+
+class SubmissionRelationList(SubmissionRelationMixin, ListCreateAPIView):
+    ordering = 'id'
+    ordering_fields = ['id']
+
+    def perform_create(self, serializer):
+        # has_object_permission() is not called when creating a new relation.
+        # Check whether user is maintainer of every project a submission is
+        # part of
+        maintains = self.request.user.maintains
+        submissions = serializer.validated_data['submissions']
+        MaintainerPermission.check_user_maintains_all(maintains, submissions)
+        serializer.save(by=self.request.user)
+
+
+class SubmissionRelationDetail(SubmissionRelationMixin,
+                               RetrieveUpdateDestroyAPIView):
+    pass
diff --git a/patchwork/models.py b/patchwork/models.py
index a92203b24ff2..9ae3370e896b 100644
--- a/patchwork/models.py
+++ b/patchwork/models.py
@@ -415,6 +415,9 @@ class CoverLetter(Submission):
                        kwargs={'project_id': self.project.linkname,
                                'msgid': self.url_msgid})
 
+    def get_absolute_api_url(self):
+        return reverse('api-cover-detail', kwargs={'pk': self.id})
+
     def get_mbox_url(self):
         return reverse('cover-mbox',
                        kwargs={'project_id': self.project.linkname,
@@ -604,6 +607,9 @@ class Patch(Submission):
                        kwargs={'project_id': self.project.linkname,
                                'msgid': self.url_msgid})
 
+    def get_absolute_api_url(self):
+        return reverse('api-patch-detail', kwargs={'pk': self.id})
+
     def get_mbox_url(self):
         return reverse('patch-mbox',
                        kwargs={'project_id': self.project.linkname,
diff --git a/patchwork/tests/api/test_relation.py b/patchwork/tests/api/test_relation.py
new file mode 100644
index 000000000000..5b1a04f13670
--- /dev/null
+++ b/patchwork/tests/api/test_relation.py
@@ -0,0 +1,181 @@
+# Patchwork - automated patch tracking system
+# Copyright (C) 2019, Bayerische Motoren Werke Aktiengesellschaft (BMW AG)
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+import unittest
+
+import six
+from django.conf import settings
+from django.urls import reverse
+
+from patchwork.tests.api import utils
+from patchwork.tests.utils import create_cover
+from patchwork.tests.utils import create_maintainer
+from patchwork.tests.utils import create_patches
+from patchwork.tests.utils import create_project
+from patchwork.tests.utils import create_relation
+from patchwork.tests.utils import create_user
+
+if settings.ENABLE_REST_API:
+    from rest_framework import status
+
+
+class UserType:
+    ANONYMOUS = 1
+    NON_MAINTAINER = 2
+    MAINTAINER = 3
+
+
+@unittest.skipUnless(settings.ENABLE_REST_API, 'requires ENABLE_REST_API')
+class TestRelationAPI(utils.APITestCase):
+    fixtures = ['default_tags']
+
+    @staticmethod
+    def api_url(item=None):
+        kwargs = {}
+        if item is None:
+            return reverse('api-relation-list', kwargs=kwargs)
+        kwargs['pk'] = item
+        return reverse('api-relation-detail', kwargs=kwargs)
+
+    def request_restricted(self, method, user_type):
+        """Assert post/delete/patch requests on the relation API."""
+        assert method in ['post', 'delete', 'patch']
+
+        # setup
+
+        project = create_project()
+        maintainer = create_maintainer(project)
+
+        if user_type == UserType.ANONYMOUS:
+            expected_status = status.HTTP_403_FORBIDDEN
+        elif user_type == UserType.NON_MAINTAINER:
+            expected_status = status.HTTP_403_FORBIDDEN
+            self.client.force_authenticate(user=create_user())
+        elif user_type == UserType.MAINTAINER:
+            if method == 'post':
+                expected_status = status.HTTP_201_CREATED
+            elif method == 'delete':
+                expected_status = status.HTTP_204_NO_CONTENT
+            else:
+                expected_status = status.HTTP_200_OK
+            self.client.force_authenticate(user=maintainer)
+        else:
+            raise ValueError
+
+        resource_id = None
+        req = None
+
+        if method == 'delete':
+            resource_id = create_relation(project=project, by=maintainer).id
+        elif method == 'post':
+            patch_ids = [p.id for p in create_patches(2, project=project)]
+            req = {'submissions': patch_ids}
+        elif method == 'patch':
+            resource_id = create_relation(project=project, by=maintainer).id
+            patch_ids = [p.id for p in create_patches(2, project=project)]
+            req = {'submissions': patch_ids}
+        else:
+            raise ValueError
+
+        # request
+
+        resp = getattr(self.client, method)(self.api_url(resource_id), req)
+
+        # check
+
+        self.assertEqual(expected_status, resp.status_code)
+
+        if resp.status_code in range(status.HTTP_200_OK,
+                                     status.HTTP_204_NO_CONTENT):
+            self.assertRequest(req, resp.data)
+
+    def assertRequest(self, request, resp):
+        if request.get('id'):
+            self.assertEqual(request['id'], resp['id'])
+        send_ids = request['submissions']
+        resp_ids = [s['id'] for s in resp['submissions']]
+        six.assertCountEqual(self, resp_ids, send_ids)
+
+    def assertSerialized(self, obj, resp):
+        self.assertEqual(obj.id, resp['id'])
+        exp_ids = [s.id for s in obj.submissions.all()]
+        act_ids = [s['id'] for s in resp['submissions']]
+        six.assertCountEqual(self, exp_ids, act_ids)
+
+    def test_list_empty(self):
+        """List relation when none are present."""
+        resp = self.client.get(self.api_url())
+        self.assertEqual(status.HTTP_200_OK, resp.status_code)
+        self.assertEqual(0, len(resp.data))
+
+    @utils.store_samples('relation-list')
+    def test_list(self):
+        """List relations."""
+        relation = create_relation()
+
+        resp = self.client.get(self.api_url())
+        self.assertEqual(status.HTTP_200_OK, resp.status_code)
+        self.assertEqual(1, len(resp.data))
+        self.assertSerialized(relation, resp.data[0])
+
+    def test_detail(self):
+        """Show relation."""
+        relation = create_relation()
+
+        resp = self.client.get(self.api_url(relation.id))
+        self.assertEqual(status.HTTP_200_OK, resp.status_code)
+        self.assertSerialized(relation, resp.data)
+
+    @utils.store_samples('relation-create-error-forbidden')
+    def test_create_anonymous(self):
+        self.request_restricted('post', UserType.ANONYMOUS)
+
+    def test_create_non_maintainer(self):
+        self.request_restricted('post', UserType.NON_MAINTAINER)
+
+    @utils.store_samples('relation-create')
+    def test_create_maintainer(self):
+        self.request_restricted('post', UserType.MAINTAINER)
+
+    @utils.store_samples('relation-update-error-forbidden')
+    def test_update_anonymous(self):
+        self.request_restricted('patch', UserType.ANONYMOUS)
+
+    def test_update_non_maintainer(self):
+        self.request_restricted('patch', UserType.NON_MAINTAINER)
+
+    @utils.store_samples('relation-update')
+    def test_update_maintainer(self):
+        self.request_restricted('patch', UserType.MAINTAINER)
+
+    @utils.store_samples('relation-delete-error-forbidden')
+    def test_delete_anonymous(self):
+        self.request_restricted('delete', UserType.ANONYMOUS)
+
+    def test_delete_non_maintainer(self):
+        self.request_restricted('delete', UserType.NON_MAINTAINER)
+
+    @utils.store_samples('relation-update')
+    def test_delete_maintainer(self):
+        self.request_restricted('delete', UserType.MAINTAINER)
+
+    def test_submission_conflict(self):
+        project = create_project()
+        maintainer = create_maintainer(project)
+        self.client.force_authenticate(user=maintainer)
+        relation = create_relation(by=maintainer, project=project)
+        submission_ids = [s.id for s in relation.submissions.all()]
+
+        # try to create a new relation with a new submission (cover) and
+        # submissions already bound to another relation
+        cover = create_cover(project=project)
+        submission_ids.append(cover.id)
+        req = {'submissions': submission_ids}
+        resp = self.client.post(self.api_url(), req)
+        self.assertEqual(status.HTTP_409_CONFLICT, resp.status_code)
+
+        # try to patch relation
+        resp = self.client.patch(self.api_url(relation.id), req)
+        self.assertEqual(status.HTTP_200_OK, resp.status_code)
diff --git a/patchwork/tests/utils.py b/patchwork/tests/utils.py
index 577183d0986c..ffe90976233e 100644
--- a/patchwork/tests/utils.py
+++ b/patchwork/tests/utils.py
@@ -16,6 +16,7 @@ from patchwork.models import Check
 from patchwork.models import Comment
 from patchwork.models import CoverLetter
 from patchwork.models import Patch
+from patchwork.models import SubmissionRelation
 from patchwork.models import Person
 from patchwork.models import Project
 from patchwork.models import Series
@@ -347,3 +348,17 @@ def create_covers(count=1, **kwargs):
         kwargs (dict): Overrides for various cover letter fields
     """
     return _create_submissions(create_cover, count, **kwargs)
+
+
+def create_relation(count_patches=2, by=None, **kwargs):
+    if not by:
+        project = create_project()
+        kwargs['project'] = project
+        by = create_maintainer(project)
+    relation = SubmissionRelation.objects.create(by=by)
+    values = {
+        'related': relation
+    }
+    values.update(kwargs)
+    create_patches(count_patches, **values)
+    return relation
diff --git a/patchwork/urls.py b/patchwork/urls.py
index dcdcfb49e67e..92095f62c7b9 100644
--- a/patchwork/urls.py
+++ b/patchwork/urls.py
@@ -187,6 +187,7 @@ if settings.ENABLE_REST_API:
     from patchwork.api import patch as api_patch_views  # noqa
     from patchwork.api import person as api_person_views  # noqa
     from patchwork.api import project as api_project_views  # noqa
+    from patchwork.api import relation as api_relation_views  # noqa
     from patchwork.api import series as api_series_views  # noqa
     from patchwork.api import user as api_user_views  # noqa
 
@@ -256,9 +257,19 @@ if settings.ENABLE_REST_API:
             name='api-cover-comment-list'),
     ]
 
+    api_1_2_patterns = [
+        url(r'^relations/$',
+            api_relation_views.SubmissionRelationList.as_view(),
+            name='api-relation-list'),
+        url(r'^relations/(?P<pk>[^/]+)/$',
+            api_relation_views.SubmissionRelationDetail.as_view(),
+            name='api-relation-detail'),
+    ]
+
     urlpatterns += [
         url(r'^api/(?:(?P<version>(1.0|1.1|1.2))/)?', include(api_patterns)),
         url(r'^api/(?:(?P<version>(1.1|1.2))/)?', include(api_1_1_patterns)),
+        url(r'^api/(?:(?P<version>1.2)/)?', include(api_1_2_patterns)),
 
         # token change
         url(r'^user/generate-token/$', user_views.generate_token,
diff --git a/releasenotes/notes/add-submission-relations-c96bb6c567b416d8.yaml b/releasenotes/notes/add-submission-relations-c96bb6c567b416d8.yaml
new file mode 100644
index 000000000000..cb877991cd55
--- /dev/null
+++ b/releasenotes/notes/add-submission-relations-c96bb6c567b416d8.yaml
@@ -0,0 +1,10 @@
+---
+features:
+  - |
+    Submissions (cover letters or patches) can now be related to other ones
+    (e.g. revisions). Relations can be set via the REST API by maintainers
+    (currently only for submissions of projects they maintain)
+api:
+  - |
+    Relations are available via ``/relations/`` and
+    ``/relations/{relationID}/`` endpoints.