Fix cursor_to_xml in tableforest false mode

It only produced <row> elements but no wrapping <table> element.

By contrast, cursor_to_xmlschema produced a schema that is now correct
but did not previously match the XML data produced by cursor_to_xml.

In passing, also fix a minor misunderstanding about moving cursors in
the tests related to this.

Reported-by: filip@jirsak.org
Based-on-patch-by: Thomas Munro <thomas.munro@enterprisedb.com>

src/backend/utils/adt/xml.c

@@ -149,6 +149,10 @@ static int xml_xpathobjtoxmlarray(xmlXPathObjectPtr xpathobj,
 static xmlChar *pg_xmlCharStrndup(char *str, size_t len);
 #endif   /* USE_LIBXML */
 
+static void xmldata_root_element_start(StringInfo result, const char *eltname,
+						   const char *xmlschema, const char *targetns,
+						   bool top_level);
+static void xmldata_root_element_end(StringInfo result, const char *eltname);
 static StringInfo query_to_xml_internal(const char *query, char *tablename,
 					  const char *xmlschema, bool nulls, bool tableforest,
 					  const char *targetns, bool top_level);
@@ -2451,6 +2455,12 @@ cursor_to_xml(PG_FUNCTION_ARGS)
 
 	initStringInfo(&result);
 
+	if (!tableforest)
+	{
+		xmldata_root_element_start(&result, "table", NULL, targetns, true);
+		appendStringInfoChar(&result, '\n');
+	}
+
 	SPI_connect();
 	portal = SPI_cursor_find(name);
 	if (portal == NULL)
@@ -2465,6 +2475,9 @@ cursor_to_xml(PG_FUNCTION_ARGS)
 
 	SPI_finish();
 
+	if (!tableforest)
+		xmldata_root_element_end(&result, "table");
+
 	PG_RETURN_XML_P(stringinfo_to_xmltype(&result));
 }
 

src/test/regress/expected/xmlmap.out

@@ -696,10 +696,47 @@ SELECT cursor_to_xml('xc'::refcursor, 5, false, true, '');
  
 (1 row)
 
-MOVE FIRST IN xc;
+SELECT cursor_to_xmlschema('xc'::refcursor, false, true, '');
+                                     cursor_to_xmlschema                                      
+----------------------------------------------------------------------------------------------
+ <xsd:schema                                                                                 +
+     xmlns:xsd="http://www.w3.org/2001/XMLSchema">                                           +
+                                                                                             +
+ <xsd:simpleType name="INTEGER">                                                             +
+   <xsd:restriction base="xsd:int">                                                          +
+     <xsd:maxInclusive value="2147483647"/>                                                  +
+     <xsd:minInclusive value="-2147483648"/>                                                 +
+   </xsd:restriction>                                                                        +
+ </xsd:simpleType>                                                                           +
+                                                                                             +
+ <xsd:simpleType name="UDT.regression.pg_catalog.text">                                      +
+   <xsd:restriction base="xsd:string">                                                       +
+   </xsd:restriction>                                                                        +
+ </xsd:simpleType>                                                                           +
+                                                                                             +
+ <xsd:complexType name="RowType">                                                            +
+   <xsd:sequence>                                                                            +
+     <xsd:element name="a" type="INTEGER" minOccurs="0"></xsd:element>                       +
+     <xsd:element name="b" type="UDT.regression.pg_catalog.text" minOccurs="0"></xsd:element>+
+   </xsd:sequence>                                                                           +
+ </xsd:complexType>                                                                          +
+                                                                                             +
+ <xsd:element name="row" type="RowType"/>                                                    +
+                                                                                             +
+ </xsd:schema>
+(1 row)
+
+MOVE BACKWARD ALL IN xc;
 SELECT cursor_to_xml('xc'::refcursor, 5, true, false, '');
                          cursor_to_xml                         
----------------
+---------------------------------------------------------------
+ <table xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">+
+                                                              +
+ <row>                                                        +
+   <a>-1</a>                                                  +
+   <b xsi:nil="true"/>                                        +
+ </row>                                                       +
+                                                              +
  <row>                                                        +
    <a>1</a>                                                   +
    <b>one</b>                                                 +
@@ -710,6 +747,7 @@ SELECT cursor_to_xml('xc'::refcursor, 5, true, false, '');
    <b>two</b>                                                 +
  </row>                                                       +
                                                               +
+ </table>                                                     +
  
 (1 row)
 

src/test/regress/expected/xmlmap_1.out

@@ -78,7 +78,11 @@ SELECT cursor_to_xml('xc'::refcursor, 5, false, true, '');
 ERROR:  unsupported XML feature
 DETAIL:  This functionality requires the server to be built with libxml support.
 HINT:  You need to rebuild PostgreSQL using --with-libxml.
-MOVE FIRST IN xc;
+SELECT cursor_to_xmlschema('xc'::refcursor, false, true, '');
+ERROR:  unsupported XML feature
+DETAIL:  This functionality requires the server to be built with libxml support.
+HINT:  You need to rebuild PostgreSQL using --with-libxml.
+MOVE BACKWARD ALL IN xc;
 SELECT cursor_to_xml('xc'::refcursor, 5, true, false, '');
 ERROR:  unsupported XML feature
 DETAIL:  This functionality requires the server to be built with libxml support.

src/test/regress/sql/xmlmap.sql

@@ -30,7 +30,8 @@ SELECT query_to_xml_and_xmlschema('SELECT * FROM testxmlschema.test1', true, tru
 
 DECLARE xc CURSOR WITH HOLD FOR SELECT * FROM testxmlschema.test1 ORDER BY 1, 2;
 SELECT cursor_to_xml('xc'::refcursor, 5, false, true, '');
-MOVE FIRST IN xc;
+SELECT cursor_to_xmlschema('xc'::refcursor, false, true, '');
+MOVE BACKWARD ALL IN xc;
 SELECT cursor_to_xml('xc'::refcursor, 5, true, false, '');
 SELECT cursor_to_xmlschema('xc'::refcursor, true, false, '');