From: Peter Eisentraut <peter_e@gmx.net>
Date: Wed, 7 Jan 2015 04:06:13 +0000 (-0500)
Subject: Fix namespace handling in xpath function
X-Git-Tag: REL9_0_19~24
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cebb3f032079fccb2c3224ba6d3eb39e987d4da9;p=thirdparty%2Fpostgresql.git

Fix namespace handling in xpath function

Previously, the xml value resulting from an xpath query would not have
namespace declarations if the namespace declarations were attached to
an ancestor element in the input xml value.  That means the output value
was not correct XML.  Fix that by running the result value through
xmlCopyNode(), which produces the correct namespace declarations.

Author: Ali Akbar <the.apaan@gmail.com>
---

diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index 46f8987fd76..b2a9d50587a 100644
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -3286,19 +3286,34 @@ xml_xmlnodetoxmltype(xmlNodePtr cur)
 	if (cur->type == XML_ELEMENT_NODE)
 	{
 		xmlBufferPtr buf;
+		xmlNodePtr	cur_copy;
 
 		buf = xmlBufferCreate();
+
+		/*
+		 * The result of xmlNodeDump() won't contain namespace definitions
+		 * from parent nodes, but xmlCopyNode() duplicates a node along with
+		 * its required namespace definitions.
+		 */
+		cur_copy = xmlCopyNode(cur, 1);
+
+		if (cur_copy == NULL)
+			xml_ereport(ERROR, ERRCODE_OUT_OF_MEMORY,
+						"could not copy node");
+
 		PG_TRY();
 		{
-			xmlNodeDump(buf, NULL, cur, 0, 1);
+			xmlNodeDump(buf, NULL, cur_copy, 0, 1);
 			result = xmlBuffer_to_xmltype(buf);
 		}
 		PG_CATCH();
 		{
+			xmlFreeNode(cur_copy);
 			xmlBufferFree(buf);
 			PG_RE_THROW();
 		}
 		PG_END_TRY();
+		xmlFreeNode(cur_copy);
 		xmlBufferFree(buf);
 	}
 	else
diff --git a/src/test/regress/expected/xml.out b/src/test/regress/expected/xml.out
index 7db5f917bed..1f165a6cd8e 100644
--- a/src/test/regress/expected/xml.out
+++ b/src/test/regress/expected/xml.out
@@ -496,6 +496,21 @@ SELECT xpath('//loc:piece/@id', '<local:data xmlns:local="http://127.0.0.1"><loc
  {1,2}
 (1 row)
 
+SELECT xpath('//loc:piece', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
+                                                                     xpath                                                                      
+------------------------------------------------------------------------------------------------------------------------------------------------
+ {"<local:piece xmlns:local=\"http://127.0.0.1\" id=\"1\">number one</local:piece>","<local:piece xmlns:local=\"http://127.0.0.1\" id=\"2\"/>"}
+(1 row)
+
+SELECT xpath('//loc:piece', '<local:data xmlns:local="http://127.0.0.1" xmlns="http://127.0.0.2"><local:piece id="1"><internal>number one</internal><internal2/></local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
+                                        xpath                                         
+--------------------------------------------------------------------------------------
+ {"<local:piece xmlns:local=\"http://127.0.0.1\" xmlns=\"http://127.0.0.2\" id=\"1\">+
+   <internal>number one</internal>                                                   +
+   <internal2/>                                                                      +
+ </local:piece>","<local:piece xmlns:local=\"http://127.0.0.1\" id=\"2\"/>"}
+(1 row)
+
 SELECT xpath('//b', '<a>one <b>two</b> three <b>etc</b></a>');
           xpath          
 -------------------------
diff --git a/src/test/regress/expected/xml_1.out b/src/test/regress/expected/xml_1.out
index d654056b08b..15f93e687d3 100644
--- a/src/test/regress/expected/xml_1.out
+++ b/src/test/regress/expected/xml_1.out
@@ -450,6 +450,18 @@ LINE 1: SELECT xpath('//loc:piece/@id', '<local:data xmlns:local="ht...
                                         ^
 DETAIL:  This functionality requires the server to be built with libxml support.
 HINT:  You need to rebuild PostgreSQL using --with-libxml.
+SELECT xpath('//loc:piece', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
+ERROR:  unsupported XML feature
+LINE 1: SELECT xpath('//loc:piece', '<local:data xmlns:local="http:/...
+                                    ^
+DETAIL:  This functionality requires the server to be built with libxml support.
+HINT:  You need to rebuild PostgreSQL using --with-libxml.
+SELECT xpath('//loc:piece', '<local:data xmlns:local="http://127.0.0.1" xmlns="http://127.0.0.2"><local:piece id="1"><internal>number one</internal><internal2/></local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
+ERROR:  unsupported XML feature
+LINE 1: SELECT xpath('//loc:piece', '<local:data xmlns:local="http:/...
+                                    ^
+DETAIL:  This functionality requires the server to be built with libxml support.
+HINT:  You need to rebuild PostgreSQL using --with-libxml.
 SELECT xpath('//b', '<a>one <b>two</b> three <b>etc</b></a>');
 ERROR:  unsupported XML feature
 LINE 1: SELECT xpath('//b', '<a>one <b>two</b> three <b>etc</b></a>'...
diff --git a/src/test/regress/sql/xml.sql b/src/test/regress/sql/xml.sql
index 1e5026b04c8..6eb7deded00 100644
--- a/src/test/regress/sql/xml.sql
+++ b/src/test/regress/sql/xml.sql
@@ -162,6 +162,8 @@ SELECT xpath(NULL, NULL) IS NULL FROM xmltest;
 SELECT xpath('', '<!-- error -->');
 SELECT xpath('//text()', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>');
 SELECT xpath('//loc:piece/@id', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
+SELECT xpath('//loc:piece', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
+SELECT xpath('//loc:piece', '<local:data xmlns:local="http://127.0.0.1" xmlns="http://127.0.0.2"><local:piece id="1"><internal>number one</internal><internal2/></local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
 SELECT xpath('//b', '<a>one <b>two</b> three <b>etc</b></a>');
 
 -- External entity references should not leak filesystem information.