Bug 1822513: Determine current version by checking for status completed

Preconditions such as ClusterVersion overrides should block all upgrades
including z-level upgrades. However other preconditions should not be
block z-level upgrades.

Currently, when upgrades are performed using `oc adm upgrade` CVO will
check if it is a z-level upgrade by comaparing the minor level version
of the desired update with the minor level version of the currently
installed version. The currently installed version is determined by
simply using the first entry in version history however this is
incorrect since that entry will be the version being upgraded to, i.e.
the desired version. A side-effect of this is that when the
`--to-image option` is used, this first entry will have an empty version
string and therefore the z-level upgrade check will always return false
and preconditions are always checked.
Instead, this change iterates through the version history until it finds
the first version with update State of Completed which will be the
currently installed version. If no Completed version is found the
originally installed version is returned.

Author: jottofar

pkg/payload/precondition/clusterversion/upgradable_test.go

@@ -116,7 +116,7 @@ func TestUpgradeableRun(t *testing.T) {
 				},
 			}
 			if len(tc.currVersion) > 0 {
-				clusterVersion.Status.History = append(clusterVersion.Status.History, configv1.UpdateHistory{Version: tc.currVersion})
+				clusterVersion.Status.History = append(clusterVersion.Status.History, configv1.UpdateHistory{Version: tc.currVersion, State: configv1.CompletedUpdate})
 			}
 			if tc.upgradeable != nil {
 				clusterVersion.Status.Conditions = append(clusterVersion.Status.Conditions, configv1.ClusterOperatorStatusCondition{

pkg/payload/precondition/clusterversion/upgradeable.go

@@ -62,8 +62,10 @@ func (pf *Upgradeable) Run(ctx context.Context, releaseContext precondition.Rele
 		return nil
 	}
 
-	currentMinor := getEffectiveMinor(cv.Status.History[0].Version)
+	currentVersion := getCurrentVersion(cv.Status.History)
+	currentMinor := getEffectiveMinor(currentVersion)
 	desiredMinor := getEffectiveMinor(releaseContext.DesiredVersion)
+	klog.V(5).Infof("currentMinor %s releaseContext.DesiredVersion %s desiredMinor %s", currentMinor, releaseContext.DesiredVersion, desiredMinor)
 
 	// if there is no difference in the minor version (4.y.z where 4.y is the same for current and desired), then we can still upgrade
 	if currentMinor == desiredMinor {
@@ -82,6 +84,20 @@ func (pf *Upgradeable) Run(ctx context.Context, releaseContext precondition.Rele
 // Name returns Name for the precondition.
 func (pf *Upgradeable) Name() string { return "ClusterVersionUpgradeable" }
 
+// getCurrentVersion determines and returns the cluster's current version by iterating through the
+// provided update history until it finds the first version with update State of Completed. If a
+// Completed version is not found the version of the oldest history entry, which is the originally
+// installed version, is returned.
+func getCurrentVersion(history []configv1.UpdateHistory) string {
+	for _, h := range history {
+		if h.State == configv1.CompletedUpdate {
+			klog.V(5).Infof("Cluster current version=%s", h.Version)
+			return h.Version
+		}
+	}
+	return history[len(history)-1].Version
+}
+
 // getEffectiveMinor attempts to do a simple parse of the version provided.  If it does not parse, the value is considered
 // empty string, which works for the comparison done here for equivalence.
 func getEffectiveMinor(version string) string {