ifaces: Allow partial consuming port interface from ignore to up

Given a bridge `br0` with `eth1` and `eth2` ports, all of them are
`state: ignore`. When applying this state,

```yaml
interfaces:
- name: br0
  type: linux-bridge
  state: up
- name: eth1
  type: ethernet
  state: up
```

nmstate should partially convert br0 and eth1 to managed state and
leaving eth2 untouched.

Both unit and integration test case included.

Signed-off-by: Gris Ge <fge@redhat.com>

rust/src/lib/ifaces/inter_ifaces_controller.rs

@@ -168,12 +168,37 @@ fn handle_changed_ports_of_iface(
 ) -> Result<(), NmstateError> {
     let desire_port_names = match iface.ports() {
         Some(p) => HashSet::from_iter(p.iter().cloned()),
-        None => return Ok(()),
+        None => {
+            if let Some(cur_iface) =
+                cur_ifaces.get_iface(iface.name(), iface.iface_type())
+            {
+                if cur_iface.is_ignore() {
+                    // Desire state would like to convert from ignore and
+                    // preserving existing port lists
+                    match cur_iface.ports().map(|ports| {
+                        HashSet::<&str>::from_iter(ports.iter().cloned())
+                    }) {
+                        Some(p) => p,
+                        None => return Ok(()),
+                    }
+                } else {
+                    return Ok(());
+                }
+            } else {
+                return Ok(());
+            }
+        }
     };
 
     let current_port_names = cur_ifaces
         .get_iface(iface.name(), iface.iface_type())
-        .and_then(|cur_iface| cur_iface.ports())
+        .and_then(|cur_iface| {
+            if cur_iface.is_ignore() {
+                None
+            } else {
+                cur_iface.ports()
+            }
+        })
         .map(|ports| HashSet::<&str>::from_iter(ports.iter().cloned()))
         .unwrap_or_default();
 

tests/integration/nm/linux_bridge_test.py

@@ -300,3 +300,44 @@ def test_ignore_interface_mentioned_in_port_list(
             f"nmcli -g GENERAL.STATE d show {DUMMY1}".split(), check=True
         )[1]
     )
+
+
+def test_partially_consume_linux_bridge_port(
+    external_managed_bridge_with_unmanaged_ports,
+):
+    desired_state = {
+        Interface.KEY: [
+            {
+                Interface.NAME: BRIDGE0,
+                Interface.STATE: InterfaceState.UP,
+            },
+            {
+                Interface.NAME: DUMMY0,
+                Interface.STATE: InterfaceState.UP,
+            },
+        ]
+    }
+    libnmstate.apply(desired_state)
+
+    current_state = show_only((BRIDGE0,))
+    bridge_state = current_state[Interface.KEY][0][LB.CONFIG_SUBTREE]
+    port_names = [port[LB.Port.NAME] for port in bridge_state[LB.PORT_SUBTREE]]
+    assert port_names == [DUMMY0, DUMMY1]
+    assert (
+        "connected"
+        in exec_cmd(
+            f"nmcli -g GENERAL.STATE d show {BRIDGE0}".split(), check=True
+        )[1]
+    )
+    assert (
+        "connected"
+        in exec_cmd(
+            f"nmcli -g GENERAL.STATE d show {DUMMY0}".split(), check=True
+        )[1]
+    )
+    assert (
+        "unmanaged"
+        in exec_cmd(
+            f"nmcli -g GENERAL.STATE d show {DUMMY1}".split(), check=True
+        )[1]
+    )