[libvirt] [PATCH] Fix virsh snapshot-list error reporting

[Jim Fehlig]

Noticed that the expected "not supported" error is dropped when
invoking 'virsh snapshot-list dom' on a Xen installation running
the libxl driver

 virsh snapshot-list test
 error: Invalid snapshot: virDomainSnapshotFree

The error is overwritten by a call to virDomainSnapshotFree
in cleanup code within cmdSnapshotList.  Prevent overwritting
the real error by not calling virDomainSnapshotFree with a NULL
virDomainSnapshotPtr.
---

This is one possible fix for the bug.  The other would be to
silently return in virDomainSnapshotFree on a NULL
virDomainSnapshotPtr.

 tools/virsh-snapshot.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/virsh-snapshot.c b/tools/virsh-snapshot.c
index cfe8ee9..db9715b 100644
--- a/tools/virsh-snapshot.c
+++ b/tools/virsh-snapshot.c
@@ -1678,7 +1678,8 @@ cleanup:
     vshSnapshotListFree(snaplist);
     VIR_FREE(parent_snap);
     VIR_FREE(state);
-    virDomainSnapshotFree(start);
+    if (start)
+        virDomainSnapshotFree(start);
     xmlXPathFreeContext(ctxt);
     xmlFreeDoc(xml);
     VIR_FREE(doc);
-- 
1.8.1.4