[BUG?] XMLSERIALIZE( ... INDENT) won't work with blank nodes

Hi,

While testing a feature reported by Pavel in this thread[1] I realized
that elements containing whitespaces between them won't be indented with
XMLSERIALIZE( ... INDENT)

SELECT xmlserialize(DOCUMENT '<foo><bar>42</bar></foo>' AS text INDENT);

  xmlserialize   
-----------------
 <foo>          +
   <bar>42</bar>+
 </foo>         +
 
(1 row)

SELECT xmlserialize(DOCUMENT '<foo> <bar>42</bar> </foo>'::xml AS text
INDENT);
        xmlserialize        
----------------------------
 <foo> <bar>42</bar> </foo>+
 
(1 row)

Other products have a different approach[2]

Perhaps simply setting xmltotext_with_options' parameter "perserve_whitespace" to false when XMLSERIALIZE(.. INDENT) would do the trick.

doc = xml_parse(data, xmloption_arg, !indent ? true : false,
GetDatabaseEncoding(),
&parsed_xmloptiontype, &content_nodes,
(Node *) &escontext);

(diff attached)

SELECT xmlserialize(DOCUMENT '<foo> <bar>42</bar> </foo>'::xml AS text
INDENT);
xmlserialize
-----------------
<foo> +
<bar>42</bar>+
</foo> +

(1 row)

If this is indeed the way to go I can update the regression tests accordingly.

Best,

--
Jim

1 - https://www.postgresql.org/message-id/cbd68a31-9776-4742-9c09-4344a4c5e6dc%40uni-muenster.de
2 - https://dbfiddle.uk/zdKnfsqX