There's an optimization in virBufferAdd which returns early when the length of the added string is 0 (given that auto-indent is disabled). The optimization causes inconsistent behaviour between these two cases: virBufferAdd(buf, "", 0); // this doesn't initialize the buffer and virBufferAdd(buf, "", -1); //this initializes the buffer Since using an empty string is used to prime the buffer to an empty string it can be confusing. Remove the optimization. This fixes such a wrong initialization done in x86FeatureNames. Note that our code in many places expects that if no virBuffer APIs are used on a buffer object, then NULL should be retured, so we can't always prime the buffer to an empty string. Signed-off-by: Peter Krempa <pkrempa(a)redhat.com&gt; --- src/util/virbuffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/util/virbuffer.c b/src/util/virbuffer.c index ebb4108b5d..b9ddf1f5c9 100644 --- a/src/util/virbuffer.c +++ b/src/util/virbuffer.c @@ -156,7 +156,7 @@ virBufferApplyIndent(virBufferPtr buf) void virBufferAdd(virBufferPtr buf, const char *str, int len) { - if (!str || !buf || (len == 0 && buf->indent == 0)) + if (!str || !buf) return; virBufferInitialize(buf); -- 2.29.2