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Make our back branches compatible with libxml2 2.13.x.

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This back-patches HEAD commits 066e8ac6e, 6082b3d5d, e7192486d,
and 896cd266f into supported branches.  Changes:

* Use xmlAddChildList not xmlAddChild in XMLSERIALIZE
(affects v16 and up only).  This was a flat-out coding mistake
that we got away with due to lax checking in previous versions
of xmlAddChild.

* Use xmlParseInNodeContext not xmlParseBalancedChunkMemory.
This is to dodge a bug in xmlParseBalancedChunkMemory in libxm2
releases 2.13.0-2.13.2.  While that bug is now fixed upstream and
will probably never be seen in any production-oriented distro, it is
currently a problem on some more-bleeding-edge-friendly platforms.

* Suppress "chunk is not well balanced" errors from libxml2,
unless it is the only error.  This eliminates an error-reporting
discrepancy between 2.13 and older releases.  This error is
almost always redundant with previous errors, if not flat-out
inappropriate, which is why 2.13 changed the behavior and why
nobody's likely to miss it.

Erik Wienhold and Tom Lane, per report from Frank Streitzig.

Discussion: https://postgr.es/m/trinity-b0161630-d230-4598-9ebc-7a23acdb37cb-1720186432160@3c-app-gmx-bap25
Discussion: https://postgr.es/m/trinity-361ba18b-541a-4fe7-bc63-655ae3a7d599-1720259822452@3c-app-gmx-bs01
This commit is contained in:
Tom Lane 2024-07-10 20:15:52 -04:00
parent 4506d18a98
commit a9747be272
3 changed files with 66 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

90
src/backend/utils/adt/xml.c
View File

@ -757,7 +757,7 @@ xmltotext_with_options(xmltype *data, XmlOptionType xmloption_arg, bool indent)
/* This attaches root to doc, so we need not free it separately. */
xmlDocSetRootElement(doc, root);
xmlAddChild(root, content_nodes);
xmlAddChildList(root, content_nodes);
/*
* We use this node to insert newlines in the dump. Note: in at
@ -1696,9 +1696,9 @@ xml_doctype_in_content(const xmlChar *str)
* XmlOptionType actually used to parse the input (typically the same as
* xmloption_arg, but a DOCTYPE node in the input can force DOCUMENT mode).
*
* If parsed_nodes isn't NULL and the input is not an XML document, the list
* of parsed nodes from the xmlParseBalancedChunkMemory call will be returned
* to *parsed_nodes.
* If parsed_nodes isn't NULL and we parse in CONTENT mode, the list
* of parsed nodes from the xmlParseInNodeContext call will be returned
* to *parsed_nodes. (It is caller's responsibility to free that.)
*
* Errors normally result in ereport(ERROR), but if escontext is an
* ErrorSaveContext, then "safe" errors are reported there instead, and the
@ -1750,6 +1750,7 @@ xml_parse(text *data, XmlOptionType xmloption_arg,
PG_TRY();
{
bool parse_as_document = false;
int options;
int res_code;
size_t count = 0;
xmlChar *version = NULL;
@ -1758,11 +1759,6 @@ xml_parse(text *data, XmlOptionType xmloption_arg,
/* Any errors here are reported as hard ereport's */
xmlInitParser();
ctxt = xmlNewParserCtxt();
if (ctxt == NULL || xmlerrcxt->err_occurred)
xml_ereport(xmlerrcxt, ERROR, ERRCODE_OUT_OF_MEMORY,
"could not allocate parser context");
/* Decide whether to parse as document or content */
if (xmloption_arg == XMLOPTION_DOCUMENT)
parse_as_document = true;
@ -1785,6 +1781,18 @@ xml_parse(text *data, XmlOptionType xmloption_arg,
parse_as_document = true;
}
/*
* Select parse options.
*
* Note that here we try to apply DTD defaults (XML_PARSE_DTDATTR)
* according to SQL/XML:2008 GR 10.16.7.d: 'Default values defined by
* internal DTD are applied'. As for external DTDs, we try to support
* them too (see SQL/XML:2008 GR 10.16.7.e), but that doesn't really
* happen because xmlPgEntityLoader prevents it.
*/
options = XML_PARSE_NOENT | XML_PARSE_DTDATTR
| (preserve_whitespace ? 0 : XML_PARSE_NOBLANKS);
/* initialize output parameters */
if (parsed_xmloptiontype != NULL)
*parsed_xmloptiontype = parse_as_document ? XMLOPTION_DOCUMENT :
@ -1794,18 +1802,16 @@ xml_parse(text *data, XmlOptionType xmloption_arg,
if (parse_as_document)
{
/*
* Note, that here we try to apply DTD defaults
* (XML_PARSE_DTDATTR) according to SQL/XML:2008 GR 10.16.7.d:
* 'Default values defined by internal DTD are applied'. As for
* external DTDs, we try to support them too, (see SQL/XML:2008 GR
* 10.16.7.e)
*/
ctxt = xmlNewParserCtxt();
if (ctxt == NULL || xmlerrcxt->err_occurred)
xml_ereport(xmlerrcxt, ERROR, ERRCODE_OUT_OF_MEMORY,
"could not allocate parser context");
doc = xmlCtxtReadDoc(ctxt, utf8string,
NULL,
NULL, /* no URL */
"UTF-8",
XML_PARSE_NOENT | XML_PARSE_DTDATTR
| (preserve_whitespace ? 0 : XML_PARSE_NOBLANKS));
options);
if (doc == NULL || xmlerrcxt->err_occurred)
{
/* Use original option to decide which error code to report */
@ -1822,6 +1828,9 @@ xml_parse(text *data, XmlOptionType xmloption_arg,
}
else
{
xmlNodePtr root;
/* set up document with empty root node to be the context node */
doc = xmlNewDoc(version);
if (doc == NULL || xmlerrcxt->err_occurred)
xml_ereport(xmlerrcxt, ERROR, ERRCODE_OUT_OF_MEMORY,
@ -1834,19 +1843,38 @@ xml_parse(text *data, XmlOptionType xmloption_arg,
"could not allocate XML document");
doc->standalone = standalone;
root = xmlNewNode(NULL, (const xmlChar *) "content-root");
if (root == NULL || xmlerrcxt->err_occurred)
xml_ereport(xmlerrcxt, ERROR, ERRCODE_OUT_OF_MEMORY,
"could not allocate xml node");
/* This attaches root to doc, so we need not free it separately. */
xmlDocSetRootElement(doc, root);
/* allow empty content */
if (*(utf8string + count))
{
res_code = xmlParseBalancedChunkMemory(doc, NULL, NULL, 0,
utf8string + count,
parsed_nodes);
if (res_code != 0 || xmlerrcxt->err_occurred)
xmlNodePtr node_list = NULL;
xmlParserErrors res;
res = xmlParseInNodeContext(root,
(char *) utf8string + count,
strlen((char *) utf8string + count),
options,
&node_list);
if (res != XML_ERR_OK || xmlerrcxt->err_occurred)
{
xmlFreeNodeList(node_list);
xml_errsave(escontext, xmlerrcxt,
ERRCODE_INVALID_XML_CONTENT,
"invalid XML content");
goto fail;
}
if (parsed_nodes != NULL)
*parsed_nodes = node_list;
else
xmlFreeNodeList(node_list);
}
}
@ -1866,7 +1894,8 @@ fail:
}
PG_END_TRY();
xmlFreeParserCtxt(ctxt);
if (ctxt != NULL)
xmlFreeParserCtxt(ctxt);
pg_xml_done(xmlerrcxt, false);
@ -2085,6 +2114,19 @@ xml_errorHandler(void *data, PgXmlErrorPtr error)
switch (domain)
{
case XML_FROM_PARSER:
/*
* XML_ERR_NOT_WELL_BALANCED is typically reported after some
* other, more on-point error. Furthermore, libxml2 2.13 reports
* it under a completely different set of rules than prior
* versions. To avoid cross-version behavioral differences,
* suppress it so long as we already logged some error.
*/
if (error->code == XML_ERR_NOT_WELL_BALANCED &&
xmlerrcxt->err_occurred)
return;
/* fall through */
case XML_FROM_NONE:
case XML_FROM_MEMORY:
case XML_FROM_IO:

9
src/test/regress/expected/xml.out
View File

@ -254,17 +254,11 @@ ERROR: invalid XML content
DETAIL: line 1: xmlParseEntityRef: no name
<invalidentity>&</invalidentity>
^
line 1: chunk is not well balanced
<invalidentity>&</invalidentity>
^
SELECT xmlparse(content '<undefinedentity>&idontexist;</undefinedentity>');
ERROR: invalid XML content
DETAIL: line 1: Entity 'idontexist' not defined
<undefinedentity>&idontexist;</undefinedentity>
^
line 1: chunk is not well balanced
<undefinedentity>&idontexist;</undefinedentity>
^
SELECT xmlparse(content '<invalidns xmlns=''&lt;''/>');
xmlparse
---------------------------
@ -283,9 +277,6 @@ DETAIL: line 1: Entity 'idontexist' not defined
<twoerrors>&idontexist;</unbalanced>
^
line 1: Opening and ending tag mismatch: twoerrors line 1 and unbalanced
<twoerrors>&idontexist;</unbalanced>
^
line 1: chunk is not well balanced
<twoerrors>&idontexist;</unbalanced>
^
SELECT xmlparse(content '<nosuchprefix:tag/>');

3
src/test/regress/expected/xml_2.out
View File

@ -250,13 +250,11 @@ ERROR: invalid XML content
DETAIL: line 1: xmlParseEntityRef: no name
<invalidentity>&</invalidentity>
^
line 1: chunk is not well balanced
SELECT xmlparse(content '<undefinedentity>&idontexist;</undefinedentity>');
ERROR: invalid XML content
DETAIL: line 1: Entity 'idontexist' not defined
<undefinedentity>&idontexist;</undefinedentity>
^
line 1: chunk is not well balanced
SELECT xmlparse(content '<invalidns xmlns=''&lt;''/>');
xmlparse
---------------------------
@ -275,7 +273,6 @@ DETAIL: line 1: Entity 'idontexist' not defined
<twoerrors>&idontexist;</unbalanced>
^
line 1: Opening and ending tag mismatch: twoerrors line 1 and unbalanced
line 1: chunk is not well balanced
SELECT xmlparse(content '<nosuchprefix:tag/>');
xmlparse
---------------------