Reject restores from backups not in a completed or partially failed phase (#9792)

* Add phase check validations in restore controller

Signed-off-by: subhramit <subhramit.bb@live.in>

* Adapt existing tests

Signed-off-by: subhramit <subhramit.bb@live.in>

* Add tests

Signed-off-by: subhramit <subhramit.bb@live.in>

* Update doc

Signed-off-by: subhramit <subhramit.bb@live.in>

* Add changelog

Signed-off-by: Subhramit Basu <subhramit.bb@live.in>

* Update pkg/controller/restore_controller_test.go

Signed-off-by: Subhramit Basu <subhramit.bb@live.in>

---------

Signed-off-by: subhramit <subhramit.bb@live.in>
Signed-off-by: Subhramit Basu <subhramit.bb@live.in>

pkg/controller/restore_controller.go

@@ -399,6 +399,17 @@ func (r *restoreReconciler) validateAndComplete(restore *api.Restore) (backupInf
 		return backupInfo{}, nil
 	}
 
+	// reject restores from backups that are not in a usable phase
+	switch info.backup.Status.Phase {
+	case api.BackupPhaseCompleted, api.BackupPhasePartiallyFailed:
+		// ok
+	default:
+		restore.Status.ValidationErrors = append(restore.Status.ValidationErrors,
+			fmt.Sprintf("backup %q is in phase %q and cannot be used as a restore source",
+				info.backup.Name, info.backup.Status.Phase))
+		return backupInfo{}, nil
+	}
+
 	// Fill in the ScheduleName so it's easier to consume for metrics.
 	if restore.Spec.ScheduleName == "" {
 		restore.Spec.ScheduleName = info.backup.GetLabels()[api.ScheduleNameLabel]