There was a recent change in libxml2 that caused a trouble for us. To us, <metadata/> in domain or network XMLs are just opaque value where management application can store whatever data it finds fit. At XML parser/formatter level, we just make a copy of the element during parsing and then format it back. For formatting we use xmlNodeDump() which allows caller to specify level of indentation. Previously, the indentation was not applied onto the very first line, but as of v2.9.12-2-g85b1792e libxml2 is applying indentation also on the first line.
This does not work well with out virBuffer because as soon as we call virBufferAsprintf() to append <metadata/> element, virBufferAsprintf() will apply another level of indentation. Instead of version checking, let's skip any indentation added by libxml2 before virBufferAsprintf() is called. Note, the problem is only when telling xmlNodeDump() to use indentation, i.e. level argument is not zero. Therefore, virXMLNodeToString() which also calls xmlNodeDump() is safe as it passes zero. Tested-by: Bjoern Walk <bw...@linux.ibm.com> Signed-off-by: Michal Privoznik <mpriv...@redhat.com> --- src/util/virxml.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/src/util/virxml.c b/src/util/virxml.c index 91c6f6b02e..4360b15486 100644 --- a/src/util/virxml.c +++ b/src/util/virxml.c @@ -1723,6 +1723,7 @@ virXMLFormatMetadata(virBuffer *buf, xmlNodePtr metadata) { g_autoptr(xmlBuffer) xmlbuf = NULL; + const char *xmlbufContent = NULL; int oldIndentTreeOutput = xmlIndentTreeOutput; if (!metadata) @@ -1745,7 +1746,12 @@ virXMLFormatMetadata(virBuffer *buf, return -1; } - virBufferAsprintf(buf, "%s\n", (char *) xmlBufferContent(xmlbuf)); + /* After libxml2-v2.9.12-2-g85b1792e even the first line is indented. + * But virBufferAsprintf() also adds indentation. Skip one of them. */ + xmlbufContent = (const char *) xmlBufferContent(xmlbuf); + virSkipSpaces(&xmlbufContent); + + virBufferAsprintf(buf, "%s\n", xmlbufContent); xmlIndentTreeOutput = oldIndentTreeOutput; return 0; -- 2.26.3