From edf095116c6ac8a229f1b778fda17b49114c1766 Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <sebastian@pipping.org>
Date: Fri, 7 May 2021 16:30:30 +0200
Subject: [PATCH 1/4] xmlwf.1: Add public external DocBook identifier to
 doctype

.. so that we can throw validation tools at it.
---
 expat/doc/xmlwf.xml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/expat/doc/xmlwf.xml b/expat/doc/xmlwf.xml
index 0977a4f2..a5b9dd54 100644
--- a/expat/doc/xmlwf.xml
+++ b/expat/doc/xmlwf.xml
@@ -1,4 +1,5 @@
-<!DOCTYPE refentry [
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+          "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
   <!-- Fill in your name for FIRSTNAME and SURNAME. -->
   <!ENTITY dhfirstname "<firstname>Scott</firstname>">
   <!ENTITY dhsurname   "<surname>Bronson</surname>">

From 283f024a4e2557f012604ecde7d87ead8b93c565 Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <sebastian@pipping.org>
Date: Fri, 7 May 2021 16:39:47 +0200
Subject: [PATCH 2/4] xmlwf.1: Fix DocBook validity

---
 expat/doc/xmlwf.xml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/expat/doc/xmlwf.xml b/expat/doc/xmlwf.xml
index a5b9dd54..1105bff4 100644
--- a/expat/doc/xmlwf.xml
+++ b/expat/doc/xmlwf.xml
@@ -50,11 +50,11 @@
     </cmdsynopsis>
     <cmdsynopsis>
       <command>&dhpackage;</command>
-      <option>-h</option>
+      <arg choice="plain"><option>-h</option></arg>
     </cmdsynopsis>
     <cmdsynopsis>
       <command>&dhpackage;</command>
-      <option>-v</option>
+      <arg choice="plain"><option>-v</option></arg>
     </cmdsynopsis>
   </refsynopsisdiv>
  

From 55dbc442000a1ff609d82201c8cb062c06bca12f Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <sebastian@pipping.org>
Date: Fri, 7 May 2021 17:00:07 +0200
Subject: [PATCH 3/4] doc/reference.html: Fix XML validity

---
 expat/doc/reference.html | 4 ++--
 expat/doc/style.css      | 6 ++++++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/expat/doc/reference.html b/expat/doc/reference.html
index 1e635bed..1b37071f 100644
--- a/expat/doc/reference.html
+++ b/expat/doc/reference.html
@@ -2486,10 +2486,10 @@ have been allocated by <code><a href="#XML_MemMalloc"
 
 <hr />
 
-  <footer>
+  <div class="footer">
     Found a bug in the documentation?
     <a href="https://github.com/libexpat/libexpat/issues">Please file a bug report.</a>
-  </footer>
+  </div>
 
 </div>
 </body>
diff --git a/expat/doc/style.css b/expat/doc/style.css
index 4af91aaf..e4751f3f 100644
--- a/expat/doc/style.css
+++ b/expat/doc/style.css
@@ -49,3 +49,9 @@ dl dt:nth-child(1n+2) {
 .cpp-symbols dt {
   font-family: monospace;
 }
+
+/* Resemble style of <footer> which is not part of xhtml1-strict */
+.footer {
+  font-size: var(--ok-fs-5);
+  color: var(--ok-tc-1);
+}

From e43dab0c4400362e94b92ab5b28472c06d14cc3d Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <sebastian@pipping.org>
Date: Fri, 7 May 2021 16:30:12 +0200
Subject: [PATCH 4/4] Actions: Ensure well-formed and valid XML

---
 .github/workflows/valid-xml.yml | 56 +++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 .github/workflows/valid-xml.yml

diff --git a/.github/workflows/valid-xml.yml b/.github/workflows/valid-xml.yml
new file mode 100644
index 00000000..ab2d3fd9
--- /dev/null
+++ b/.github/workflows/valid-xml.yml
@@ -0,0 +1,56 @@
+#                          __  __            _
+#                       ___\ \/ /_ __   __ _| |_
+#                      / _ \\  /| '_ \ / _` | __|
+#                     |  __//  \| |_) | (_| | |_
+#                      \___/_/\_\ .__/ \__,_|\__|
+#                               |_| XML parser
+#
+# Copyright (c) 2021 Sebastian Pipping <sebastian@pipping.org>
+# Licensed under the MIT license:
+#
+# Permission is  hereby granted,  free of charge,  to any  person obtaining
+# a  copy  of  this  software   and  associated  documentation  files  (the
+# "Software"),  to  deal in  the  Software  without restriction,  including
+# without  limitation the  rights  to use,  copy,  modify, merge,  publish,
+# distribute, sublicense, and/or sell copies of the Software, and to permit
+# persons  to whom  the Software  is  furnished to  do so,  subject to  the
+# following conditions:
+#
+# The above copyright  notice and this permission notice  shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE  SOFTWARE  IS  PROVIDED  "AS  IS",  WITHOUT  WARRANTY  OF  ANY  KIND,
+# EXPRESS  OR IMPLIED,  INCLUDING  BUT  NOT LIMITED  TO  THE WARRANTIES  OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+# NO EVENT SHALL THE AUTHORS OR  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+# DAMAGES OR  OTHER LIABILITY, WHETHER  IN AN  ACTION OF CONTRACT,  TORT OR
+# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+# USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+name: Ensure well-formed and valid XML
+
+on:
+  pull_request:
+  push:
+  schedule:
+    - cron: '0 2 * * 5'  # Every Friday at 2am
+
+jobs:
+  checks:
+    name: Ensure well-formed and valid XML
+    runs-on: ubuntu-20.04
+    steps:
+    - uses: actions/checkout@v2.3.4
+
+    - name: Install build dependencies
+      run: |-
+        sudo apt-get install --yes --no-install-recommends -V \
+            docbook \
+            libxml2-utils \
+            w3c-sgml-lib
+
+    - name: Ensure well-formed and valid XML
+      run: |
+        set -x
+        xmllint --noout --valid expat/doc/reference.html
+        xmllint --noout --valid expat/doc/xmlwf.xml