[PATCH 5/5] conf: checkpoint: Don't require <domain> when redefining checkpoints

[Peter Krempa]

The domain definition stored with a checkpoint isn't used currently
apart from matching disks when creating a new checkpoints.

As some users of the incremental backup API want to provide backups in
offline mode under their control (obviously while compying with our
documentation on how the on-disk state should be handled) and then want
to define the checkpoint for live use, supplying a <domain> sub-element
is overly complex and not actually needed by the code.

Relax the restriction when re-defining a checkpoint so that <domain> is
not necessary and add (alibistic) documentation saying that future
actions may not work if it's missing.

Signed-off-by: Peter Krempa <pkrempa at redhat.com>
---
 docs/formatcheckpoint.rst  | 12 +++++++++---
 src/conf/checkpoint_conf.c |  4 ----
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/docs/formatcheckpoint.rst b/docs/formatcheckpoint.rst
index f159f2a7a3..ff3f1e8c00 100644
--- a/docs/formatcheckpoint.rst
+++ b/docs/formatcheckpoint.rst
@@ -1,3 +1,5 @@
+.. role:: since
+
 Checkpoint XML format
 =====================

@@ -103,12 +105,16 @@ The top-level ``domaincheckpoint`` element may contain the following elements:
    A readonly representation of the inactive `domain
    configuration <formatdomain.html>`__ at the time the checkpoint was created.
    This element may be omitted for output brevity by supplying the
-   ``VIR_DOMAIN_CHECKPOINT_XML_NO_DOMAIN`` flag, but the resulting XML is no
-   longer viable for use with the ``VIR_DOMAIN_CHECKPOINT_CREATE_REDEFINE`` flag
-   of ``virDomainCheckpointCreateXML()``. The domain will have
+   ``VIR_DOMAIN_CHECKPOINT_XML_NO_DOMAIN`` flag. The domain will have
    security-sensitive information omitted unless the flag
    ``VIR_DOMAIN_CHECKPOINT_XML_SECURE`` is provided on a read-write connection.

+   ``virDomainCheckpointCreateXML()`` requires that the ``<domain>`` is present
+   when used with ``VIR_DOMAIN_CHECKPOINT_CREATE_REDEFINE``.
+   :since:`Since 7.0.0` the ``<domain>`` element can be omitted when redefining
+   a checkpoint, but hypervisors may not support certain operations if it's
+   missing.
+
 Examples
 --------

diff --git a/src/conf/checkpoint_conf.c b/src/conf/checkpoint_conf.c
index 2071494d52..2df5e41495 100644
--- a/src/conf/checkpoint_conf.c
+++ b/src/conf/checkpoint_conf.c
@@ -165,10 +165,6 @@ virDomainCheckpointDefParse(xmlXPathContextPtr ctxt,
                                                     domainParseFlags);
             if (!def->parent.dom)
                 return NULL;
-        } else {
-            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                           _("missing domain in checkpoint redefine"));
-            return NULL;
         }
     } else if (virDomainXMLOptionRunMomentPostParse(xmlopt, &def->parent) < 0) {
         return NULL;
-- 
2.28.0