Fix some whitespace issues in XMLSERIALIZE(... INDENT).

We must drop whitespace while parsing the input, else libxml2
will include "blank" nodes that interfere with the desired
indentation behavior.  The end result is that we didn't indent
nodes separated by whitespace.

Also, it seems that libxml2 may add a trailing newline when working
in DOCUMENT mode.  This is semantically insignificant, so strip it.

This is in the gray area between being a bug fix and a definition
change.  However, the INDENT option is still pretty new (since v16),
so I think we can get away with changing this in stable branches.
Hence, back-patch to v16.

Jim Jones

Discussion: https://postgr.es/m/[email protected]

5 files changed, 84 insertions, 23 deletions

diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index 447e72b21eb..1a07876cd59 100644
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -677,8 +677,14 @@ xmltotext_with_options(xmltype *data, XmlOptionType xmloption_arg, bool indent)
 	}
 
 #ifdef USE_LIBXML
-	/* Parse the input according to the xmloption */
-	doc = xml_parse(data, xmloption_arg, true, GetDatabaseEncoding(),
+
+	/*
+	 * Parse the input according to the xmloption.
+	 *
+	 * preserve_whitespace is set to false in case we are indenting, otherwise
+	 * libxml2 will fail to indent elements that have whitespace between them.
+	 */
+	doc = xml_parse(data, xmloption_arg, !indent, GetDatabaseEncoding(),
 					&parsed_xmloptiontype, &content_nodes,
 					(Node *) &escontext);
 	if (doc == NULL || escontext.error_occurred)
@@ -802,7 +808,22 @@ xmltotext_with_options(xmltype *data, XmlOptionType xmloption_arg, bool indent)
 						"could not close xmlSaveCtxtPtr");
 		}
 
-		result = (text *) xmlBuffer_to_xmltype(buf);
+		/*
+		 * xmlDocContentDumpOutput may add a trailing newline, so remove that.
+		 */
+		if (xmloption_arg == XMLOPTION_DOCUMENT)
+		{
+			const char *str = (const char *) xmlBufferContent(buf);
+			int			len = xmlBufferLength(buf);
+
+			while (len > 0 && (str[len - 1] == '\n' ||
+							   str[len - 1] == '\r'))
+				len--;
+
+			result = cstring_to_text_with_len(str, len);
+		}
+		else
+			result = (text *) xmlBuffer_to_xmltype(buf);
 	}
 	PG_CATCH();
 	{
diff --git a/src/test/regress/expected/xml.out b/src/test/regress/expected/xml.out
index 93a79cda8fd..361a6f9b27c 100644
--- a/src/test/regress/expected/xml.out
+++ b/src/test/regress/expected/xml.out
@@ -485,8 +485,7 @@ SELECT xmlserialize(DOCUMENT '<foo><bar><val x="y">42</val></bar></foo>' AS text
    <bar>                +
      <val x="y">42</val>+
    </bar>               +
- </foo>                 +
- 
+ </foo>
 (1 row)
 
 SELECT xmlserialize(CONTENT  '<foo><bar><val x="y">42</val></bar></foo>' AS text INDENT);
@@ -546,8 +545,7 @@ SELECT xmlserialize(DOCUMENT '<foo><bar><val x="y">42</val><val x="y">text node<
      <val x="y">42</val>                    +
      <val x="y">text node<val>73</val></val>+
    </bar>                                   +
- </foo>                                     +
- 
+ </foo>
 (1 row)
 
 SELECT xmlserialize(CONTENT  '<foo><bar><val x="y">42</val><val x="y">text node<val>73</val></val></bar></foo>' AS text INDENT);
@@ -601,8 +599,7 @@ SELECT xmlserialize(DOCUMENT '<?xml version="1.0" encoding="UTF-8"?><foo><bar><v
    <bar>                               +
      <val>73</val>                     +
    </bar>                              +
- </foo>                                +
- 
+ </foo>
 (1 row)
 
 SELECT xmlserialize(CONTENT  '<?xml version="1.0" encoding="UTF-8"?><foo><bar><val>73</val></bar></foo>' AS text INDENT);
@@ -620,8 +617,7 @@ SELECT xmlserialize(DOCUMENT '<!DOCTYPE a><a/>' AS text INDENT);
  xmlserialize 
 --------------
  <!DOCTYPE a>+
- <a/>        +
- 
+ <a/>
 (1 row)
 
 SELECT xmlserialize(CONTENT  '<!DOCTYPE a><a/>' AS text INDENT);
@@ -638,8 +634,7 @@ SELECT xmlserialize(DOCUMENT '<foo><bar></bar></foo>' AS text INDENT);
 --------------
  <foo>       +
    <bar/>    +
- </foo>      +
- 
+ </foo>
 (1 row)
 
 SELECT xmlserialize(CONTENT  '<foo><bar></bar></foo>' AS text INDENT);
@@ -663,6 +658,24 @@ SELECT xmlserialize(CONTENT  '<foo><bar><val x="y">42</val></bar></foo>' AS text
  t
 (1 row)
 
+-- indent xml strings containing blank nodes
+SELECT xmlserialize(DOCUMENT '<foo>   <bar></bar>    </foo>' AS text INDENT);
+ xmlserialize 
+--------------
+ <foo>       +
+   <bar/>    +
+ </foo>
+(1 row)
+
+SELECT xmlserialize(CONTENT  'text node<foo>    <bar></bar>   </foo>' AS text INDENT);
+ xmlserialize 
+--------------
+ text node   +
+ <foo>       +
+   <bar/>    +
+ </foo>
+(1 row)
+
 SELECT xml '<foo>bar</foo>' IS DOCUMENT;
  ?column? 
 ----------
diff --git a/src/test/regress/expected/xml_1.out b/src/test/regress/expected/xml_1.out
index 9323b84ae21..d26e10441e8 100644
--- a/src/test/regress/expected/xml_1.out
+++ b/src/test/regress/expected/xml_1.out
@@ -443,6 +443,17 @@ ERROR:  unsupported XML feature
 LINE 1: SELECT xmlserialize(CONTENT  '<foo><bar><val x="y">42</val><...
                                      ^
 DETAIL:  This functionality requires the server to be built with libxml support.
+-- indent xml strings containing blank nodes
+SELECT xmlserialize(DOCUMENT '<foo>   <bar></bar>    </foo>' AS text INDENT);
+ERROR:  unsupported XML feature
+LINE 1: SELECT xmlserialize(DOCUMENT '<foo>   <bar></bar>    </foo>'...
+                                     ^
+DETAIL:  This functionality requires the server to be built with libxml support.
+SELECT xmlserialize(CONTENT  'text node<foo>    <bar></bar>   </foo>' AS text INDENT);
+ERROR:  unsupported XML feature
+LINE 1: SELECT xmlserialize(CONTENT  'text node<foo>    <bar></bar> ...
+                                     ^
+DETAIL:  This functionality requires the server to be built with libxml support.
 SELECT xml '<foo>bar</foo>' IS DOCUMENT;
 ERROR:  unsupported XML feature
 LINE 1: SELECT xml '<foo>bar</foo>' IS DOCUMENT;
diff --git a/src/test/regress/expected/xml_2.out b/src/test/regress/expected/xml_2.out
index f956322c693..73c2851d3f5 100644
--- a/src/test/regress/expected/xml_2.out
+++ b/src/test/regress/expected/xml_2.out
@@ -471,8 +471,7 @@ SELECT xmlserialize(DOCUMENT '<foo><bar><val x="y">42</val></bar></foo>' AS text
    <bar>                +
      <val x="y">42</val>+
    </bar>               +
- </foo>                 +
- 
+ </foo>
 (1 row)
 
 SELECT xmlserialize(CONTENT  '<foo><bar><val x="y">42</val></bar></foo>' AS text INDENT);
@@ -532,8 +531,7 @@ SELECT xmlserialize(DOCUMENT '<foo><bar><val x="y">42</val><val x="y">text node<
      <val x="y">42</val>                    +
      <val x="y">text node<val>73</val></val>+
    </bar>                                   +
- </foo>                                     +
- 
+ </foo>
 (1 row)
 
 SELECT xmlserialize(CONTENT  '<foo><bar><val x="y">42</val><val x="y">text node<val>73</val></val></bar></foo>' AS text INDENT);
@@ -587,8 +585,7 @@ SELECT xmlserialize(DOCUMENT '<?xml version="1.0" encoding="UTF-8"?><foo><bar><v
    <bar>                               +
      <val>73</val>                     +
    </bar>                              +
- </foo>                                +
- 
+ </foo>
 (1 row)
 
 SELECT xmlserialize(CONTENT  '<?xml version="1.0" encoding="UTF-8"?><foo><bar><val>73</val></bar></foo>' AS text INDENT);
@@ -606,8 +603,7 @@ SELECT xmlserialize(DOCUMENT '<!DOCTYPE a><a/>' AS text INDENT);
  xmlserialize 
 --------------
  <!DOCTYPE a>+
- <a/>        +
- 
+ <a/>
 (1 row)
 
 SELECT xmlserialize(CONTENT  '<!DOCTYPE a><a/>' AS text INDENT);
@@ -624,8 +620,7 @@ SELECT xmlserialize(DOCUMENT '<foo><bar></bar></foo>' AS text INDENT);
 --------------
  <foo>       +
    <bar/>    +
- </foo>      +
- 
+ </foo>
 (1 row)
 
 SELECT xmlserialize(CONTENT  '<foo><bar></bar></foo>' AS text INDENT);
@@ -649,6 +644,24 @@ SELECT xmlserialize(CONTENT  '<foo><bar><val x="y">42</val></bar></foo>' AS text
  t
 (1 row)
 
+-- indent xml strings containing blank nodes
+SELECT xmlserialize(DOCUMENT '<foo>   <bar></bar>    </foo>' AS text INDENT);
+ xmlserialize 
+--------------
+ <foo>       +
+   <bar/>    +
+ </foo>
+(1 row)
+
+SELECT xmlserialize(CONTENT  'text node<foo>    <bar></bar>   </foo>' AS text INDENT);
+ xmlserialize 
+--------------
+ text node   +
+ <foo>       +
+   <bar/>    +
+ </foo>
+(1 row)
+
 SELECT xml '<foo>bar</foo>' IS DOCUMENT;
  ?column? 
 ----------
diff --git a/src/test/regress/sql/xml.sql b/src/test/regress/sql/xml.sql
index 953bac09e45..f752ecb1421 100644
--- a/src/test/regress/sql/xml.sql
+++ b/src/test/regress/sql/xml.sql
@@ -168,6 +168,9 @@ SELECT xmlserialize(CONTENT  '<foo><bar></bar></foo>' AS text INDENT);
 -- 'no indent' = not using 'no indent'
 SELECT xmlserialize(DOCUMENT '<foo><bar><val x="y">42</val></bar></foo>' AS text) = xmlserialize(DOCUMENT '<foo><bar><val x="y">42</val></bar></foo>' AS text NO INDENT);
 SELECT xmlserialize(CONTENT  '<foo><bar><val x="y">42</val></bar></foo>' AS text) = xmlserialize(CONTENT '<foo><bar><val x="y">42</val></bar></foo>' AS text NO INDENT);
+-- indent xml strings containing blank nodes
+SELECT xmlserialize(DOCUMENT '<foo>   <bar></bar>    </foo>' AS text INDENT);
+SELECT xmlserialize(CONTENT  'text node<foo>    <bar></bar>   </foo>' AS text INDENT);
 
 SELECT xml '<foo>bar</foo>' IS DOCUMENT;
 SELECT xml '<foo>bar</foo><bar>foo</bar>' IS DOCUMENT;