rebase and add an extra check for xmlbuf after the xmlC14NDocDumpMemory
call:
if (nbytes < 0 || xmlbuf == NULL)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("could not canonicalize XML document")));
--
Jim
From b892f597cbb8c88cdc9db60adb4f407b5bb6c22d Mon Sep 17 00:00:00 2001
From: Jim Jones <jim.jo...@uni-muenster.de>
Date: Tue, 10 Jun 2025 10:46:24 +0200
Subject: [PATCH v18] Add xmlcanonicalize function
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
This patch adds the xmlcanonicalize function, which transforms an
XML document into its canonical form according to the W3C C14N 1.1
specification.
xmlcanonicalize(doc xml, keep_comments boolean DEFAULT true) -> xml
* doc: The XML document to be canonicalized.
* keep_comments: A flag indicating whether to preserve or discard
XML comments from the input document. If omitted, it defaults to
'true'.
This function is implemented using the xmlC14NDocDumpMemory()
function from libxml2’s Canonical XML (C14N) module.
---
doc/src/sgml/func.sgml | 50 +++++++++++++++
src/backend/catalog/system_functions.sql | 6 ++
src/backend/utils/adt/xml.c | 60 +++++++++++++++++
src/include/catalog/pg_proc.dat | 3 +
src/test/regress/expected/xml.out | 82 ++++++++++++++++++++++++
src/test/regress/expected/xml_1.out | 80 +++++++++++++++++++++++
src/test/regress/expected/xml_2.out | 82 ++++++++++++++++++++++++
src/test/regress/sql/xml.sql | 52 +++++++++++++++
8 files changed, 415 insertions(+)
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index c67688cbf5..db42d7856e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -14623,6 +14623,56 @@ SELECT xmltext('< foo & bar >');
</para>
</sect3>
+<sect3 id="functions-producing-xml-xmlcanonicalize">
+ <title><literal>xmlcanonicalize</literal></title>
+
+ <indexterm>
+ <primary>xmlcanonicalize</primary>
+ </indexterm>
+
+<synopsis>
+<function>xmlcanonicalize</function> ( <parameter>doc</parameter> <type>xml</type> [, <parameter>keep_comments</parameter> <type>boolean</type> DEFAULT <literal>true</literal>] ) <returnvalue>xml</returnvalue>
+
+</synopsis>
+
+ <para>
+ This function transforms a given XML document into its <ulink url="https://www.w3.org/TR/xml-c14n11/#Terminology";>canonical form</ulink>,
+ as defined by the <ulink url="https://www.w3.org/TR/xml-c14n11/";>W3C Canonical XML 1.1 Specification</ulink>, which standardizes the document's
+ structure and syntax to facilitate comparison and validation.
+ The <parameter>keep_comments</parameter> parameter controls whether XML comments from the input document are preserved or discarded.
+ If omitted, it defaults to <literal>true</literal>.
+ </para>
+
+ <para>
+ Example:
+<screen><![CDATA[
+SELECT
+ xmlcanonicalize(
+ '<foo>
+ <!-- a comment -->
+ <bar c="3" b="2" a="1">42</bar>
+ <empty/>
+ </foo>'::xml);
+ xmlcanonicalize
+-----------------------------------------------------------------------------
+ <foo><!-- a comment --><bar a="1" b="2" c="3">42</bar><empty></empty></foo>
+(1 row)
+
+SELECT
+ xmlcanonicalize(
+ '<foo>
+ <!-- a comment -->
+ <bar c="3" b="2" a="1">42</bar>
+ <empty/>
+ </foo>'::xml, false);
+ xmlcanonicalize
+-----------------------------------------------------------
+ <foo><bar a="1" b="2" c="3">42</bar><empty></empty></foo>
+(1 row)
+]]></screen>
+ </para>
+ </sect3>
+
<sect3 id="functions-producing-xml-xmlcomment">
<title><literal>xmlcomment</literal></title>
diff --git a/src/backend/catalog/system_functions.sql b/src/backend/catalog/system_functions.sql
index 566f308e44..15c33335dc 100644
--- a/src/backend/catalog/system_functions.sql
+++ b/src/backend/catalog/system_functions.sql
@@ -268,6 +268,12 @@ CREATE OR REPLACE FUNCTION xpath_exists(text, xml)
IMMUTABLE PARALLEL SAFE STRICT COST 1
RETURN xpath_exists($1, $2, '{}'::text[]);
+CREATE OR REPLACE FUNCTION xmlcanonicalize(xml, boolean DEFAULT true)
+ RETURNS xml
+ LANGUAGE internal
+ IMMUTABLE PARALLEL SAFE STRICT
+AS 'xmlcanonicalize';
+
CREATE OR REPLACE FUNCTION pg_sleep_for(interval)
RETURNS void
LANGUAGE sql
diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index a4150bff2e..094eb4c33e 100644
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -58,6 +58,7 @@
#include <libxml/xmlwriter.h>
#include <libxml/xpath.h>
#include <libxml/xpathInternals.h>
+#include <libxml/c14n.h>
/*
* We used to check for xmlStructuredErrorContext via a configure test; but
@@ -544,6 +545,65 @@ xmltext(PG_FUNCTION_ARGS)
#endif /* not USE_LIBXML */
}
+/*
+ * Canonicalizes the given XML document according to the W3C Canonical XML 1.1
+ * specification, using libxml2's xmlC14NDocDumpMemory().
+ *
+ * The input XML must be a well-formed document (not a fragment). The
+ * canonical form is deterministic and useful for digital signatures and
+ * comparing logically equivalent XML.
+ *
+ * The second argument determines whether comments are preserved
+ * (true) or omitted (false) in the canonicalized output.
+ */
+Datum xmlcanonicalize(PG_FUNCTION_ARGS)
+{
+#ifdef USE_LIBXML
+ xmltype *arg = PG_GETARG_XML_P(0);
+ bool keep_comments = PG_GETARG_BOOL(1);
+ text *result;
+ int nbytes;
+ xmlDocPtr doc;
+ xmlChar *xmlbuf = NULL;
+
+ /* Parse the input xmltype into a full XML document */
+ doc = xml_parse(arg, XMLOPTION_DOCUMENT, false,
+ GetDatabaseEncoding(), NULL, NULL, NULL);
+
+ /*
+ * Canonicalize the XML document into memory using Canonical XML 1.1.
+ *
+ * xmlC14NDocDumpMemory arguments:
+ * - doc: the XML document to canonicalize (already parsed above)
+ * - nodes: NULL means the entire document is canonicalized
+ * - mode: 2 selects the Canonical XML 1.1 algorithm (xmlC14NMode enum)
+ * - inclusive_ns_prefixes: NULL includes all namespaces by default
+ * - with_comments: determined by keep_comments argument
+ * - doc_txt_ptr: output buffer receiving the canonicalized XML (xmlbuf)
+ *
+ * On success, xmlbuf points to the serialized canonical form,
+ * and nbytes holds its size.
+ */
+ nbytes = xmlC14NDocDumpMemory(doc, NULL, 2, NULL, keep_comments, &xmlbuf);
+
+ if (doc)
+ xmlFreeDoc(doc);
+
+ if (nbytes < 0 || xmlbuf == NULL)
+ ereport(ERROR,
+ (errcode(ERRCODE_INTERNAL_ERROR),
+ errmsg("could not canonicalize XML document")));
+
+ result = cstring_to_text_with_len((const char *)xmlbuf, nbytes);
+
+ xmlFree(xmlbuf);
+
+ PG_RETURN_XML_P(result);
+#else
+ NO_XML_SUPPORT();
+ return 0;
+#endif /* not USE_LIBXML */
+}
/*
* TODO: xmlconcat needs to merge the notations and unparsed entities
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index d3d28a263f..d6c5b80a8f 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -9133,6 +9133,9 @@
{ oid => '3813', descr => 'generate XML text node',
proname => 'xmltext', prorettype => 'xml', proargtypes => 'text',
prosrc => 'xmltext' },
+{ oid => '3814', descr => 'generate the canonical form of an XML document',
+ proname => 'xmlcanonicalize', prorettype => 'xml', proargtypes => 'xml bool',
+ prosrc => 'xmlcanonicalize' },
{ oid => '2923', descr => 'map table contents to XML',
proname => 'table_to_xml', procost => '100', provolatile => 's',
diff --git a/src/test/regress/expected/xml.out b/src/test/regress/expected/xml.out
index 103a22a3b1..688c0fc3e9 100644
--- a/src/test/regress/expected/xml.out
+++ b/src/test/regress/expected/xml.out
@@ -1881,3 +1881,85 @@ SELECT xmltext('x'|| '<P>73</P>'::xml || .42 || true || 'j'::char);
x<P>73</P>0.42truej
(1 row)
+-- xmlserialize: canonical
+CREATE TABLE xmlcanonicalize_test (doc xml);
+INSERT INTO xmlcanonicalize_test VALUES
+ ('<?xml version="1.0" encoding="ISO-8859-1"?>
+ <!DOCTYPE doc SYSTEM "doc.dtd" [
+ <!ENTITY val "42">
+ <!ATTLIST xyz attr CDATA "default">
+ ]>
+
+ <!-- attributes and namespces will be sorted -->
+ <foo a:attr="out" b:attr="sorted" attr2="all" attr="I am"
+ xmlns:b="http://www.ietf.org";
+ xmlns:a="http://www.w3.org";
+ xmlns="http://example.org";>
+
+ <!-- Normalization of whitespace in start and end tags -->
+ <!-- Elimination of superfluous namespace declarations, as already declared in <foo> -->
+ <bar xmlns="" xmlns:a="http://www.w3.org"; >&val;</bar >
+
+ <!-- empty element will be converted to start-end tag pair -->
+ <empty/>
+
+ <!-- text will be transcoded to UTF-8 -->
+ <transcode>1</transcode>
+
+ <!-- whitespace inside tag will be preserved -->
+ <whitespace> 321 </whitespace>
+
+ <!-- empty namespace will be removed of child tag -->
+ <emptyns xmlns="" >
+ <emptyns_child xmlns=""></emptyns_child>
+ </emptyns>
+
+ <!-- CDATA section will be replaced by its value -->
+ <compute><![CDATA[value>"0" && value<"10" ?"valid":"error"]]></compute>
+ </foo> <!-- comment outside root element --> ');
+SELECT xmlcanonicalize(doc, true) FROM xmlcanonicalize_test;
+ xmlcanonicalize
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ <!-- attributes and namespces will be sorted --> +
+ <foo xmlns="http://example.org"; xmlns:a="http://www.w3.org"; xmlns:b="http://www.ietf.org"; attr="I am" attr2="all" b:attr="sorted" a:attr="out"><!-- Normalization of whitespace in start and end tags --><!-- Elimination of superfluous namespace declarations, as already declared in <foo> --><bar xmlns="">42</bar><!-- empty element will be converted to start-end tag pair --><empty></empty><!-- text will be transcoded to UTF-8 --><transcode>1</transcode><!-- whitespace inside tag will be preserved --><whitespace> 321 </whitespace><!-- empty namespace will be removed of child tag --><emptyns xmlns=""><emptyns_child></emptyns_child></emptyns><!-- CDATA section will be replaced by its value --><compute>value>"0" && value<"10" ?"valid":"error"</compute></foo>+
+ <!-- comment outside root element -->
+(1 row)
+
+SELECT xmlcanonicalize(doc, false) FROM xmlcanonicalize_test;
+ xmlcanonicalize
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ <foo xmlns="http://example.org"; xmlns:a="http://www.w3.org"; xmlns:b="http://www.ietf.org"; attr="I am" attr2="all" b:attr="sorted" a:attr="out"><bar xmlns="">42</bar><empty></empty><transcode>1</transcode><whitespace> 321 </whitespace><emptyns xmlns=""><emptyns_child></emptyns_child></emptyns><compute>value>"0" && value<"10" ?"valid":"error"</compute></foo>
+(1 row)
+
+SELECT xmlcanonicalize(doc, true)::text = xmlcanonicalize(doc)::text FROM xmlcanonicalize_test;
+ ?column?
+----------
+ t
+(1 row)
+
+SELECT xmlcanonicalize(doc, NULL) FROM xmlcanonicalize_test;
+ xmlcanonicalize
+-----------------
+
+(1 row)
+
+SELECT xmlcanonicalize(NULL, true);
+ xmlcanonicalize
+-----------------
+
+(1 row)
+
+\set VERBOSITY terse
+SELECT xmlcanonicalize('', true);
+ERROR: invalid XML document
+SELECT xmlcanonicalize(' ', true);
+ERROR: invalid XML document
+SELECT xmlcanonicalize('foo', true);
+ERROR: invalid XML document
+SELECT xmlcanonicalize('');
+ERROR: invalid XML document
+SELECT xmlcanonicalize(' ');
+ERROR: invalid XML document
+SELECT xmlcanonicalize('foo');
+ERROR: invalid XML document
+\set VERBOSITY default
diff --git a/src/test/regress/expected/xml_1.out b/src/test/regress/expected/xml_1.out
index 73c411118a..8bc3ac1c96 100644
--- a/src/test/regress/expected/xml_1.out
+++ b/src/test/regress/expected/xml_1.out
@@ -1496,3 +1496,83 @@ ERROR: unsupported XML feature
LINE 1: SELECT xmltext('x'|| '<P>73</P>'::xml || .42 || true || 'j':...
^
DETAIL: This functionality requires the server to be built with libxml support.
+-- xmlserialize: canonical
+CREATE TABLE xmlcanonicalize_test (doc xml);
+INSERT INTO xmlcanonicalize_test VALUES
+ ('<?xml version="1.0" encoding="ISO-8859-1"?>
+ <!DOCTYPE doc SYSTEM "doc.dtd" [
+ <!ENTITY val "42">
+ <!ATTLIST xyz attr CDATA "default">
+ ]>
+
+ <!-- attributes and namespces will be sorted -->
+ <foo a:attr="out" b:attr="sorted" attr2="all" attr="I am"
+ xmlns:b="http://www.ietf.org";
+ xmlns:a="http://www.w3.org";
+ xmlns="http://example.org";>
+
+ <!-- Normalization of whitespace in start and end tags -->
+ <!-- Elimination of superfluous namespace declarations, as already declared in <foo> -->
+ <bar xmlns="" xmlns:a="http://www.w3.org"; >&val;</bar >
+
+ <!-- empty element will be converted to start-end tag pair -->
+ <empty/>
+
+ <!-- text will be transcoded to UTF-8 -->
+ <transcode>1</transcode>
+
+ <!-- whitespace inside tag will be preserved -->
+ <whitespace> 321 </whitespace>
+
+ <!-- empty namespace will be removed of child tag -->
+ <emptyns xmlns="" >
+ <emptyns_child xmlns=""></emptyns_child>
+ </emptyns>
+
+ <!-- CDATA section will be replaced by its value -->
+ <compute><![CDATA[value>"0" && value<"10" ?"valid":"error"]]></compute>
+ </foo> <!-- comment outside root element --> ');
+ERROR: unsupported XML feature
+LINE 2: ('<?xml version="1.0" encoding="ISO-8859-1"?>
+ ^
+DETAIL: This functionality requires the server to be built with libxml support.
+SELECT xmlcanonicalize(doc, true) FROM xmlcanonicalize_test;
+ xmlcanonicalize
+-----------------
+(0 rows)
+
+SELECT xmlcanonicalize(doc, false) FROM xmlcanonicalize_test;
+ xmlcanonicalize
+-----------------
+(0 rows)
+
+SELECT xmlcanonicalize(doc, true)::text = xmlcanonicalize(doc)::text FROM xmlcanonicalize_test;
+ ?column?
+----------
+(0 rows)
+
+SELECT xmlcanonicalize(doc, NULL) FROM xmlcanonicalize_test;
+ xmlcanonicalize
+-----------------
+(0 rows)
+
+SELECT xmlcanonicalize(NULL, true);
+ xmlcanonicalize
+-----------------
+
+(1 row)
+
+\set VERBOSITY terse
+SELECT xmlcanonicalize('', true);
+ERROR: unsupported XML feature at character 24
+SELECT xmlcanonicalize(' ', true);
+ERROR: unsupported XML feature at character 24
+SELECT xmlcanonicalize('foo', true);
+ERROR: unsupported XML feature at character 24
+SELECT xmlcanonicalize('');
+ERROR: unsupported XML feature at character 24
+SELECT xmlcanonicalize(' ');
+ERROR: unsupported XML feature at character 24
+SELECT xmlcanonicalize('foo');
+ERROR: unsupported XML feature at character 24
+\set VERBOSITY default
diff --git a/src/test/regress/expected/xml_2.out b/src/test/regress/expected/xml_2.out
index a85d95358d..4ce36ff825 100644
--- a/src/test/regress/expected/xml_2.out
+++ b/src/test/regress/expected/xml_2.out
@@ -1867,3 +1867,85 @@ SELECT xmltext('x'|| '<P>73</P>'::xml || .42 || true || 'j'::char);
x<P>73</P>0.42truej
(1 row)
+-- xmlserialize: canonical
+CREATE TABLE xmlcanonicalize_test (doc xml);
+INSERT INTO xmlcanonicalize_test VALUES
+ ('<?xml version="1.0" encoding="ISO-8859-1"?>
+ <!DOCTYPE doc SYSTEM "doc.dtd" [
+ <!ENTITY val "42">
+ <!ATTLIST xyz attr CDATA "default">
+ ]>
+
+ <!-- attributes and namespces will be sorted -->
+ <foo a:attr="out" b:attr="sorted" attr2="all" attr="I am"
+ xmlns:b="http://www.ietf.org";
+ xmlns:a="http://www.w3.org";
+ xmlns="http://example.org";>
+
+ <!-- Normalization of whitespace in start and end tags -->
+ <!-- Elimination of superfluous namespace declarations, as already declared in <foo> -->
+ <bar xmlns="" xmlns:a="http://www.w3.org"; >&val;</bar >
+
+ <!-- empty element will be converted to start-end tag pair -->
+ <empty/>
+
+ <!-- text will be transcoded to UTF-8 -->
+ <transcode>1</transcode>
+
+ <!-- whitespace inside tag will be preserved -->
+ <whitespace> 321 </whitespace>
+
+ <!-- empty namespace will be removed of child tag -->
+ <emptyns xmlns="" >
+ <emptyns_child xmlns=""></emptyns_child>
+ </emptyns>
+
+ <!-- CDATA section will be replaced by its value -->
+ <compute><![CDATA[value>"0" && value<"10" ?"valid":"error"]]></compute>
+ </foo> <!-- comment outside root element --> ');
+SELECT xmlcanonicalize(doc, true) FROM xmlcanonicalize_test;
+ xmlcanonicalize
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ <!-- attributes and namespces will be sorted --> +
+ <foo xmlns="http://example.org"; xmlns:a="http://www.w3.org"; xmlns:b="http://www.ietf.org"; attr="I am" attr2="all" b:attr="sorted" a:attr="out"><!-- Normalization of whitespace in start and end tags --><!-- Elimination of superfluous namespace declarations, as already declared in <foo> --><bar xmlns="">42</bar><!-- empty element will be converted to start-end tag pair --><empty></empty><!-- text will be transcoded to UTF-8 --><transcode>1</transcode><!-- whitespace inside tag will be preserved --><whitespace> 321 </whitespace><!-- empty namespace will be removed of child tag --><emptyns xmlns=""><emptyns_child></emptyns_child></emptyns><!-- CDATA section will be replaced by its value --><compute>value>"0" && value<"10" ?"valid":"error"</compute></foo>+
+ <!-- comment outside root element -->
+(1 row)
+
+SELECT xmlcanonicalize(doc, false) FROM xmlcanonicalize_test;
+ xmlcanonicalize
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ <foo xmlns="http://example.org"; xmlns:a="http://www.w3.org"; xmlns:b="http://www.ietf.org"; attr="I am" attr2="all" b:attr="sorted" a:attr="out"><bar xmlns="">42</bar><empty></empty><transcode>1</transcode><whitespace> 321 </whitespace><emptyns xmlns=""><emptyns_child></emptyns_child></emptyns><compute>value>"0" && value<"10" ?"valid":"error"</compute></foo>
+(1 row)
+
+SELECT xmlcanonicalize(doc, true)::text = xmlcanonicalize(doc)::text FROM xmlcanonicalize_test;
+ ?column?
+----------
+ t
+(1 row)
+
+SELECT xmlcanonicalize(doc, NULL) FROM xmlcanonicalize_test;
+ xmlcanonicalize
+-----------------
+
+(1 row)
+
+SELECT xmlcanonicalize(NULL, true);
+ xmlcanonicalize
+-----------------
+
+(1 row)
+
+\set VERBOSITY terse
+SELECT xmlcanonicalize('', true);
+ERROR: invalid XML document
+SELECT xmlcanonicalize(' ', true);
+ERROR: invalid XML document
+SELECT xmlcanonicalize('foo', true);
+ERROR: invalid XML document
+SELECT xmlcanonicalize('');
+ERROR: invalid XML document
+SELECT xmlcanonicalize(' ');
+ERROR: invalid XML document
+SELECT xmlcanonicalize('foo');
+ERROR: invalid XML document
+\set VERBOSITY default
diff --git a/src/test/regress/sql/xml.sql b/src/test/regress/sql/xml.sql
index 0ea4f50883..4af51a9908 100644
--- a/src/test/regress/sql/xml.sql
+++ b/src/test/regress/sql/xml.sql
@@ -679,3 +679,55 @@ SELECT xmltext(' ');
SELECT xmltext('foo `$_-+?=*^%!|/\()[]{}');
SELECT xmltext('foo & <"bar">');
SELECT xmltext('x'|| '<P>73</P>'::xml || .42 || true || 'j'::char);
+
+-- xmlserialize: canonical
+CREATE TABLE xmlcanonicalize_test (doc xml);
+INSERT INTO xmlcanonicalize_test VALUES
+ ('<?xml version="1.0" encoding="ISO-8859-1"?>
+ <!DOCTYPE doc SYSTEM "doc.dtd" [
+ <!ENTITY val "42">
+ <!ATTLIST xyz attr CDATA "default">
+ ]>
+
+ <!-- attributes and namespces will be sorted -->
+ <foo a:attr="out" b:attr="sorted" attr2="all" attr="I am"
+ xmlns:b="http://www.ietf.org";
+ xmlns:a="http://www.w3.org";
+ xmlns="http://example.org";>
+
+ <!-- Normalization of whitespace in start and end tags -->
+ <!-- Elimination of superfluous namespace declarations, as already declared in <foo> -->
+ <bar xmlns="" xmlns:a="http://www.w3.org"; >&val;</bar >
+
+ <!-- empty element will be converted to start-end tag pair -->
+ <empty/>
+
+ <!-- text will be transcoded to UTF-8 -->
+ <transcode>1</transcode>
+
+ <!-- whitespace inside tag will be preserved -->
+ <whitespace> 321 </whitespace>
+
+ <!-- empty namespace will be removed of child tag -->
+ <emptyns xmlns="" >
+ <emptyns_child xmlns=""></emptyns_child>
+ </emptyns>
+
+ <!-- CDATA section will be replaced by its value -->
+ <compute><![CDATA[value>"0" && value<"10" ?"valid":"error"]]></compute>
+ </foo> <!-- comment outside root element --> ');
+
+SELECT xmlcanonicalize(doc, true) FROM xmlcanonicalize_test;
+SELECT xmlcanonicalize(doc, false) FROM xmlcanonicalize_test;
+SELECT xmlcanonicalize(doc, true)::text = xmlcanonicalize(doc)::text FROM xmlcanonicalize_test;
+SELECT xmlcanonicalize(doc, NULL) FROM xmlcanonicalize_test;
+SELECT xmlcanonicalize(NULL, true);
+
+\set VERBOSITY terse
+SELECT xmlcanonicalize('', true);
+SELECT xmlcanonicalize(' ', true);
+SELECT xmlcanonicalize('foo', true);
+SELECT xmlcanonicalize('');
+SELECT xmlcanonicalize(' ');
+SELECT xmlcanonicalize('foo');
+\set VERBOSITY default
\ No newline at end of file
--
2.34.1
