conf: Avoid formatting empty <capabilities> element

If none of the 'capabilities' features are enabled we'd still format the
opening and closing tag for the <capabilities element.

The implementation is suboptimal but will be refactored for a better
approach. This is done prior to the refactor to show that tests are not
impacted.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

src/conf/domain_conf.c

@@ -27933,8 +27933,15 @@ virDomainDefFormatFeatures(virBufferPtr buf,
                 break;
             }
 
-            virBufferAsprintf(buf, "<capabilities policy='%s'>\n",
+            virBufferAsprintf(buf, "<capabilities policy='%s'",
                               virDomainCapabilitiesPolicyTypeToString(def->features[i]));
+
+            if (!virDomainDefHasCapabilitiesFeatures(def)) {
+                virBufferAddLit(buf, "/>\n");
+                break;
+            } else {
+                virBufferAddLit(buf, ">\n");
+            }
             virBufferAdjustIndent(buf, 2);
             for (j = 0; j < VIR_DOMAIN_CAPS_FEATURE_LAST; j++) {
                 if (def->caps_features[j] != VIR_TRISTATE_SWITCH_ABSENT)

tests/lxcconf2xmldata/lxcconf2xml-blkiotune.xml

@@ -25,8 +25,7 @@
   </os>
   <features>
     <privnet/>
-    <capabilities policy='allow'>
-    </capabilities>
+    <capabilities policy='allow'/>
   </features>
   <clock offset='utc'/>
   <on_poweroff>destroy</on_poweroff>

tests/lxcconf2xmldata/lxcconf2xml-cpusettune.xml

@@ -13,8 +13,7 @@
   </os>
   <features>
     <privnet/>
-    <capabilities policy='allow'>
-    </capabilities>
+    <capabilities policy='allow'/>
   </features>
   <clock offset='utc'/>
   <on_poweroff>destroy</on_poweroff>

tests/lxcconf2xmldata/lxcconf2xml-cputune.xml

@@ -15,8 +15,7 @@
   </os>
   <features>
     <privnet/>
-    <capabilities policy='allow'>
-    </capabilities>
+    <capabilities policy='allow'/>
   </features>
   <clock offset='utc'/>
   <on_poweroff>destroy</on_poweroff>

tests/lxcconf2xmldata/lxcconf2xml-idmap.xml

@@ -14,8 +14,7 @@
   </idmap>
   <features>
     <privnet/>
-    <capabilities policy='allow'>
-    </capabilities>
+    <capabilities policy='allow'/>
   </features>
   <clock offset='utc'/>
   <on_poweroff>destroy</on_poweroff>

tests/lxcconf2xmldata/lxcconf2xml-macvlannetwork.xml

@@ -9,8 +9,7 @@
     <init>/sbin/init</init>
   </os>
   <features>
-    <capabilities policy='allow'>
-    </capabilities>
+    <capabilities policy='allow'/>
   </features>
   <clock offset='utc'/>
   <on_poweroff>destroy</on_poweroff>

tests/lxcconf2xmldata/lxcconf2xml-memtune.xml

@@ -15,8 +15,7 @@
   </os>
   <features>
     <privnet/>
-    <capabilities policy='allow'>
-    </capabilities>
+    <capabilities policy='allow'/>
   </features>
   <clock offset='utc'/>
   <on_poweroff>destroy</on_poweroff>

tests/lxcconf2xmldata/lxcconf2xml-miscnetwork.xml

@@ -9,8 +9,7 @@
     <init>/sbin/init</init>
   </os>
   <features>
-    <capabilities policy='allow'>
-    </capabilities>
+    <capabilities policy='allow'/>
   </features>
   <clock offset='utc'/>
   <on_poweroff>destroy</on_poweroff>

tests/lxcconf2xmldata/lxcconf2xml-nonenetwork.xml

@@ -9,8 +9,7 @@
     <init>/sbin/init</init>
   </os>
   <features>
-    <capabilities policy='allow'>
-    </capabilities>
+    <capabilities policy='allow'/>
   </features>
   <clock offset='utc'/>
   <on_poweroff>destroy</on_poweroff>

tests/lxcconf2xmldata/lxcconf2xml-nonetwork.xml

@@ -10,8 +10,7 @@
   </os>
   <features>
     <privnet/>
-    <capabilities policy='allow'>
-    </capabilities>
+    <capabilities policy='allow'/>
   </features>
   <clock offset='utc'/>
   <on_poweroff>destroy</on_poweroff>

tests/lxcconf2xmldata/lxcconf2xml-physnetwork.xml

@@ -9,8 +9,7 @@
     <init>/sbin/init</init>
   </os>
   <features>
-    <capabilities policy='allow'>
-    </capabilities>
+    <capabilities policy='allow'/>
   </features>
   <clock offset='utc'/>
   <on_poweroff>destroy</on_poweroff>

tests/lxcconf2xmldata/lxcconf2xml-vlannetwork.xml

@@ -9,8 +9,7 @@
     <init>/sbin/init</init>
   </os>
   <features>
-    <capabilities policy='allow'>
-    </capabilities>
+    <capabilities policy='allow'/>
   </features>
   <clock offset='utc'/>
   <on_poweroff>destroy</on_poweroff>