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Fix minor deficiencies in XMLTABLE, xpath(), xmlexists()

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Correctly process nodes of more types than previously.  In some cases,
nodes were being ignored (nothing was output); in other cases, trying to
return them resulted in errors about unrecognized nodes.  In yet other
cases, necessary escaping (of XML special characters) was not being
done.  Fix all those (as far as the authors could find) and add
regression tests cases verifying the new behavior.

I (Álvaro) was of two minds about backpatching these changes.  They do
seem bugfixes that would benefit most users of the affected functions;
but on the other hand it would change established behavior in minor
releases, so it seems prudent not to.

Authors: Pavel Stehule, Markus Winand, Chapman Flack
Discussion:
   https://postgr.es/m/CAFj8pRA6J25CtAZ2TuRvxK3gat7-bBUYh0rfE2yM7Hj9GD14Dg@mail.gmail.com
   https://postgr.es/m/8BDB0627-2105-4564-AA76-7849F028B96E@winand.at

The elephant in the room as pointed out by Chapman Flack, not fixed in
this commit, is that we still have XMLTABLE operating on XPath 1.0
instead of the standard-mandated XQuery (or even its subset XPath 2.0).
Fixing that is a major undertaking, however.
This commit is contained in:
Alvaro Herrera
2019-03-07 15:21:56 -03:00
parent 1d33858406
commit 251cf2e27b
6 changed files with 167 additions and 81 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
src/test/regress/expected/xml.out
View File

@ -1210,9 +1210,9 @@ SELECT xmltable.* FROM xmldata, LATERAL xmltable('/ROWS/ROW[COUNTRY_NAME="Japan"
(2 rows)
SELECT * FROM xmltable('/root' passing '<root><element>a1a<!-- aaaa -->a2a<?aaaaa?> <!--z--> bbbb<x>xxx</x>cccc</element></root>' COLUMNS element text);
element
-------------------
a1aa2a bbbbcccc
element
----------------------
a1aa2a bbbbxxxcccc
(1 row)
SELECT * FROM xmltable('/root' passing '<root><element>a1a<!-- aaaa -->a2a<?aaaaa?> <!--z--> bbbb<x>xxx</x>cccc</element></root>' COLUMNS element text PATH 'element/text()'); -- should fail
@ -1493,3 +1493,24 @@ SELECT xmltable.* FROM xmltest2, LATERAL xmltable(('/d/r/' || lower(_path) || 'c
14
(4 rows)
-- XPath result can be boolean or number too
SELECT * FROM XMLTABLE('*' PASSING '<a>a</a>' COLUMNS a xml PATH '.', b text PATH '.', c text PATH '"hi"', d boolean PATH '. = "a"', e integer PATH 'string-length(.)');
a | b | c | d | e
----------+---+----+---+---
<a>a</a> | a | hi | t | 1
(1 row)
\x
SELECT * FROM XMLTABLE('*' PASSING '<e>pre<!--c1--><?pi arg?><![CDATA[&ent1]]><n2>&amp;deep</n2>post</e>' COLUMNS x xml PATH 'node()', y xml PATH '/');
-[ RECORD 1 ]-----------------------------------------------------------
x | pre<!--c1--><?pi arg?><![CDATA[&ent1]]><n2>&amp;deep</n2>post
y | <e>pre<!--c1--><?pi arg?><![CDATA[&ent1]]><n2>&amp;deep</n2>post</e>+
|
\x
SELECT * FROM XMLTABLE('.' PASSING XMLELEMENT(NAME a) columns a varchar(20) PATH '"<foo/>"', b xml PATH '"<foo/>"');
a | b
--------+--------------
<foo/> | &lt;foo/&gt;
(1 row)

19
src/test/regress/expected/xml_1.out
View File

@ -1343,3 +1343,22 @@ SELECT xmltable.* FROM xmltest2, LATERAL xmltable(('/d/r/' || lower(_path) || 'c
---
(0 rows)
-- XPath result can be boolean or number too
SELECT * FROM XMLTABLE('*' PASSING '<a>a</a>' COLUMNS a xml PATH '.', b text PATH '.', c text PATH '"hi"', d boolean PATH '. = "a"', e integer PATH 'string-length(.)');
ERROR: unsupported XML feature
LINE 1: SELECT * FROM XMLTABLE('*' PASSING '<a>a</a>' COLUMNS a xml ...
^
DETAIL: This functionality requires the server to be built with libxml support.
HINT: You need to rebuild PostgreSQL using --with-libxml.
\x
SELECT * FROM XMLTABLE('*' PASSING '<e>pre<!--c1--><?pi arg?><![CDATA[&ent1]]><n2>&amp;deep</n2>post</e>' COLUMNS x xml PATH 'node()', y xml PATH '/');
ERROR: unsupported XML feature
LINE 1: SELECT * FROM XMLTABLE('*' PASSING '<e>pre<!--c1--><?pi arg?...
^
DETAIL: This functionality requires the server to be built with libxml support.
HINT: You need to rebuild PostgreSQL using --with-libxml.
\x
SELECT * FROM XMLTABLE('.' PASSING XMLELEMENT(NAME a) columns a varchar(20) PATH '"<foo/>"', b xml PATH '"<foo/>"');
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.

27
src/test/regress/expected/xml_2.out
View File

@ -1190,9 +1190,9 @@ SELECT xmltable.* FROM xmldata, LATERAL xmltable('/ROWS/ROW[COUNTRY_NAME="Japan"
(2 rows)
SELECT * FROM xmltable('/root' passing '<root><element>a1a<!-- aaaa -->a2a<?aaaaa?> <!--z--> bbbb<x>xxx</x>cccc</element></root>' COLUMNS element text);
element
-------------------
a1aa2a bbbbcccc
element
----------------------
a1aa2a bbbbxxxcccc
(1 row)
SELECT * FROM xmltable('/root' passing '<root><element>a1a<!-- aaaa -->a2a<?aaaaa?> <!--z--> bbbb<x>xxx</x>cccc</element></root>' COLUMNS element text PATH 'element/text()'); -- should fail
@ -1473,3 +1473,24 @@ SELECT xmltable.* FROM xmltest2, LATERAL xmltable(('/d/r/' || lower(_path) || 'c
14
(4 rows)
-- XPath result can be boolean or number too
SELECT * FROM XMLTABLE('*' PASSING '<a>a</a>' COLUMNS a xml PATH '.', b text PATH '.', c text PATH '"hi"', d boolean PATH '. = "a"', e integer PATH 'string-length(.)');
a | b | c | d | e
----------+---+----+---+---
<a>a</a> | a | hi | t | 1
(1 row)
\x
SELECT * FROM XMLTABLE('*' PASSING '<e>pre<!--c1--><?pi arg?><![CDATA[&ent1]]><n2>&amp;deep</n2>post</e>' COLUMNS x xml PATH 'node()', y xml PATH '/');
-[ RECORD 1 ]-----------------------------------------------------------
x | pre<!--c1--><?pi arg?><![CDATA[&ent1]]><n2>&amp;deep</n2>post
y | <e>pre<!--c1--><?pi arg?><![CDATA[&ent1]]><n2>&amp;deep</n2>post</e>+
|
\x
SELECT * FROM XMLTABLE('.' PASSING XMLELEMENT(NAME a) columns a varchar(20) PATH '"<foo/>"', b xml PATH '"<foo/>"');
a | b
--------+--------------
<foo/> | &lt;foo/&gt;
(1 row)

8
src/test/regress/sql/xml.sql
View File

@ -595,3 +595,11 @@ INSERT INTO xmltest2 VALUES('<d><r><dc>2</dc></r></d>', 'D');
SELECT xmltable.* FROM xmltest2, LATERAL xmltable('/d/r' PASSING x COLUMNS a int PATH '' || lower(_path) || 'c');
SELECT xmltable.* FROM xmltest2, LATERAL xmltable(('/d/r/' || lower(_path) || 'c') PASSING x COLUMNS a int PATH '.');
SELECT xmltable.* FROM xmltest2, LATERAL xmltable(('/d/r/' || lower(_path) || 'c') PASSING x COLUMNS a int PATH 'x' DEFAULT ascii(_path) - 54);
-- XPath result can be boolean or number too
SELECT * FROM XMLTABLE('*' PASSING '<a>a</a>' COLUMNS a xml PATH '.', b text PATH '.', c text PATH '"hi"', d boolean PATH '. = "a"', e integer PATH 'string-length(.)');
\x
SELECT * FROM XMLTABLE('*' PASSING '<e>pre<!--c1--><?pi arg?><![CDATA[&ent1]]><n2>&amp;deep</n2>post</e>' COLUMNS x xml PATH 'node()', y xml PATH '/');
\x
SELECT * FROM XMLTABLE('.' PASSING XMLELEMENT(NAME a) columns a varchar(20) PATH '"<foo/>"', b xml PATH '"<foo/>"');