fix podman container restore without CreateNetNS

When a container does not use the default podman netns, for example
--network none or --network ns:/path a restore would fail because the
specgen check validates that c.config.StaticMAC is nil but the
unmarshaller sets it to an empty slice.

While we could make the check use len() > 0 I feel like it is more
common to check with != nil for ip and mac addresses.
Adding omitempty tag makes the json marshal/unmarshal work correctly.
This should not cause any issues.

Fixes containers#14389

Signed-off-by: Paul Holzinger <[email protected]>

libpod/container_config.go

@@ -243,12 +243,12 @@ type ContainerNetworkConfig struct {
 	// This cannot be set unless CreateNetNS is set.
 	// If not set, the container will be dynamically assigned an IP by CNI.
 	// Deprecated: Do no use this anymore, this is only for DB backwards compat.
-	StaticIP net.IP `json:"staticIP"`
+	StaticIP net.IP `json:"staticIP,omitempty"`
 	// StaticMAC is a static MAC to request for the container.
 	// This cannot be set unless CreateNetNS is set.
 	// If not set, the container will be dynamically assigned a MAC by CNI.
 	// Deprecated: Do no use this anymore, this is only for DB backwards compat.
-	StaticMAC types.HardwareAddr `json:"staticMAC"`
+	StaticMAC types.HardwareAddr `json:"staticMAC,omitempty"`
 	// PortMappings are the ports forwarded to the container's network
 	// namespace
 	// These are not used unless CreateNetNS is true

test/e2e/checkpoint_test.go

@@ -676,8 +676,8 @@ var _ = Describe("Podman checkpoint", func() {
 	})
 	It("podman checkpoint and restore container with root file-system changes using --ignore-rootfs during restore", func() {
 		// Start the container
-		localRunString := getRunString([]string{"--rm", ALPINE, "top"})
-		session := podmanTest.Podman(localRunString)
+		// test that restore works without network namespace (https://github.com/containers/podman/issues/14389)
+		session := podmanTest.Podman([]string{"run", "--network=none", "-d", "--rm", ALPINE, "top"})
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(Exit(0))
 		Expect(podmanTest.NumberOfContainersRunning()).To(Equal(1))