Fix DocBook reader mathml regression...

...caused by the switch in XML libraries.
Also fixed a similar issue in JATS.
Closes #7173.

2 files changed, 140 insertions, 1 deletions

diff --git a/test/command/7173.md b/test/command/7173.md
new file mode 100644
index 000000000..2599dc19b
--- /dev/null
+++ b/test/command/7173.md
@@ -0,0 +1,137 @@
+```
+% pandoc -f docbook -t latex
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE article PUBLIC "-//W3C//DTD MathML 2.0//EN" "http://www.w3.org/Math/DTD/mathml2/mathml2.dtd">
+<?xml-model href="http://www.oxygenxml.com/docbook/xml/5.0/rng/dbmathml.rng" schematypens="http://relaxng.org/ns/structure/1.0"?>
+<?xml-model href="http://docbook.org/xml/5.0/rng/docbook.rng" type="application/xml" schematypens="http://purl.oclc.org/dsdl/schematron"?>
+<article xmlns="http://docbook.org/ns/docbook"
+    xmlns:xlink="http://www.w3.org/1999/xlink"
+    version="5.1">
+    <title>Untitled Document</title>
+    <para>Word</para>
+    <informalequation>
+        <alt role='tex'>1+2</alt>
+        <m:math xmlns:m="http://www.w3.org/1998/Math/MathML">
+            <m:mrow>
+                <m:mrow><m:mn>1</m:mn><m:mo>+</m:mo><m:mn>2</m:mn>
+                </m:mrow>
+            </m:mrow>
+        </m:math>
+    </informalequation>
+</article>
+^D
+Word
+
+\[1 + 2\]
+```
+
+```
+% pandoc -f docbook -t latex
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE article PUBLIC "-//W3C//DTD MathML 2.0//EN" "http://www.w3.org/Math/DTD/mathml2/mathml2.dtd">
+<?xml-model href="http://www.oxygenxml.com/docbook/xml/5.0/rng/dbmathml.rng" schematypens="http://relaxng.org/ns/structure/1.0"?>
+<?xml-model href="http://docbook.org/xml/5.0/rng/docbook.rng" type="application/xml" schematypens="http://purl.oclc.org/dsdl/schematron"?>
+<article xmlns="http://docbook.org/ns/docbook"
+    xmlns:xlink="http://www.w3.org/1999/xlink"
+    version="5.1">
+    <title>Untitled Document</title>
+    <para>Word</para>
+    <informalequation>
+        <alt role='tex'>1+2</alt>
+        <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
+            <mml:mrow>
+                <mml:mrow><mml:mn>1</mml:mn><mml:mo>+</mml:mo><mml:mn>2</mml:mn>
+                </mml:mrow>
+            </mml:mrow>
+        </mml:math>
+    </informalequation>
+</article>
+^D
+Word
+
+\[1 + 2\]
+```
+
+```
+% pandoc -f docbook -t latex
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE article PUBLIC "-//W3C//DTD MathML 2.0//EN" "http://www.w3.org/Math/DTD/mathml2/mathml2.dtd">
+<?xml-model href="http://www.oxygenxml.com/docbook/xml/5.0/rng/dbmathml.rng" schematypens="http://relaxng.org/ns/structure/1.0"?>
+<?xml-model href="http://docbook.org/xml/5.0/rng/docbook.rng" type="application/xml" schematypens="http://purl.oclc.org/dsdl/schematron"?>
+<article xmlns="http://docbook.org/ns/docbook"
+    xmlns:xlink="http://www.w3.org/1999/xlink"
+    version="5.1">
+    <title>Untitled Document</title>
+    <para>Word</para>
+    <informalequation>
+        <alt role='tex'>1+2</alt>
+        <math xmlns="http://www.w3.org/1998/Math/MathML">
+            <mrow>
+                <mrow><mn>1</mn><mo>+</mo><mn>2</mn>
+                </mrow>
+            </mrow>
+        </math>
+    </informalequation>
+</article>
+^D
+Word
+
+\[1 + 2\]
+```
+
+```
+% pandoc -f docbook -t latex
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE article PUBLIC "-//W3C//DTD MathML 2.0//EN" "http://www.w3.org/Math/DTD/mathml2/mathml2.dtd">
+<?xml-model href="http://www.oxygenxml.com/docbook/xml/5.0/rng/dbmathml.rng" schematypens="http://relaxng.org/ns/structure/1.0"?>
+<?xml-model href="http://docbook.org/xml/5.0/rng/docbook.rng" type="application/xml" schematypens="http://purl.oclc.org/dsdl/schematron"?>
+<article xmlns="http://docbook.org/ns/docbook"
+    xmlns:xlink="http://www.w3.org/1999/xlink"
+    xmlns:m="http://www.w3.org/1998/Math/MathML"
+    version="5.1">
+    <title>Untitled Document</title>
+    <para>Word</para>
+    <informalequation>
+        <alt role='tex'>1+2</alt>
+        <m:math>
+            <m:mrow>
+                <m:mrow><m:mn>1</m:mn><m:mo>+</m:mo><m:mn>2</m:mn>
+                </m:mrow>
+            </m:mrow>
+        </m:math>
+    </informalequation>
+</article>
+^D
+Word
+
+\[1 + 2\]
+```
+
+```
+% pandoc -f docbook -t latex
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE article PUBLIC "-//W3C//DTD MathML 2.0//EN" "http://www.w3.org/Math/DTD/mathml2/mathml2.dtd">
+<?xml-model href="http://www.oxygenxml.com/docbook/xml/5.0/rng/dbmathml.rng" schematypens="http://relaxng.org/ns/structure/1.0"?>
+<?xml-model href="http://docbook.org/xml/5.0/rng/docbook.rng" type="application/xml" schematypens="http://purl.oclc.org/dsdl/schematron"?>
+<article xmlns="http://docbook.org/ns/docbook"
+    xmlns:xlink="http://www.w3.org/1999/xlink"
+    xmlns:mml="http://www.w3.org/1998/Math/MathML"
+    version="5.1">
+    <title>Untitled Document</title>
+    <para>Word</para>
+    <informalequation>
+        <alt role='tex'>1+2</alt>
+        <mml:math>
+            <mml:mrow>
+                <mml:mrow><mml:mn>1</mml:mn><mml:mo>+</mml:mo><mml:mn>2</mml:mn>
+                </mml:mrow>
+            </mml:mrow>
+        </mml:math>
+    </informalequation>
+</article>
+^D
+Word
+
+\[1 + 2\]
+```
+
diff --git a/test/docbook-reader.docbook b/test/docbook-reader.docbook
index 5717d78d0..51e62942b 100644
--- a/test/docbook-reader.docbook
+++ b/test/docbook-reader.docbook
@@ -6,7 +6,9 @@
 <!ENTITY let "LET" >
 <!ENTITY case "CASE" >
 ]>
-<article>
+<article xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:mml="http://www.w3.org/1998/Math/MathML">
   <articleinfo>
     <title>Pandoc Test Suite</title>
     <authorgroup>