From 56b44fe637c040187338b51a401d8cc2f1d60612 Mon Sep 17 00:00:00 2001
From: Peter Krempa <pkrempa@redhat.com>
Date: Thu, 4 Mar 2021 18:09:42 +0100
Subject: [PATCH 018/108] virBufferAdd: Ensure that the buffer is initialized
 also when len == 0
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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@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
(cherry picked from commit 1553e7256701c725cf87bafa5d738da16f278c3d)
---
 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 b78c3debe9..1fd055f77d 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);
-- 
2.33.0