overlord/ifacestate: automatically rename connections on core snap

overlord/ifacestate/helpers.go

@@ -48,6 +48,9 @@ func (m *InterfaceManager) initialize(extraInterfaces []interfaces.Interface, ex
 	if err := m.addSnaps(); err != nil {
 		return err
 	}
+	if err := m.renameCorePlugConnection(); err != nil {
+		return err
+	}
 	if err := m.reloadConnections(""); err != nil {
 		return err
 	}
@@ -154,6 +157,35 @@ func (m *InterfaceManager) regenerateAllSecurityProfiles() error {
 	return nil
 }
 
+// renameCorePlugConnection renames one connection from "core-support" plug to
+// slot so that the plug name is "core-support-plug" while the slot is
+// unchanged. This matches a change introduced in 2.24, where the core snap no
+// longer has the "core-support" plug as that was clashing with the slot with
+// the same name.
+func (m *InterfaceManager) renameCorePlugConnection() error {
+	conns, err := getConns(m.state)
+	if err != nil {
+		return err
+	}
+	const oldPlugName = "core-support"
+	const newPlugName = "core-support-plug"
+	// old connection, note that slotRef is the same in both
+	slotRef := interfaces.SlotRef{Snap: "core", Name: oldPlugName}
+	oldPlugRef := interfaces.PlugRef{Snap: "core", Name: oldPlugName}
+	oldConnRef := interfaces.ConnRef{PlugRef: oldPlugRef, SlotRef: slotRef}
+	oldID := oldConnRef.ID()
+	// if the old connection is saved, replace it with the new connection
+	if cState, ok := conns[oldID]; ok {
+		newPlugRef := interfaces.PlugRef{Snap: "core", Name: newPlugName}
+		newConnRef := interfaces.ConnRef{PlugRef: newPlugRef, SlotRef: slotRef}
+		newID := newConnRef.ID()
+		delete(conns, oldID)
+		conns[newID] = cState
+		setConns(m.state, conns)
+	}
+	return nil
+}
+
 // reloadConnections reloads connections stored in the state in the repository.
 // Using non-empty snapName the operation can be scoped to connections
 // affecting a given snap.

overlord/ifacestate/ifacestate_test.go

@@ -1838,6 +1838,40 @@ func (s *interfaceManagerSuite) TestManagerTransitionConnectionsCoreUndo(c *C) {
 	})
 }
 
+// Test "core-support" connections that loop back to core is
+// renamed to match the rename of the plug.
+func (s *interfaceManagerSuite) TestCoreConnectionsRenamed(c *C) {
+	// Put state with old connection data.
+	s.state.Lock()
+	s.state.Set("conns", map[string]interface{}{
+		"core:core-support core:core-support": map[string]interface{}{
+			"interface": "core-support", "auto": true,
+		},
+		"snap:unrelated core:unrelated": map[string]interface{}{
+			"interface": "unrelated", "auto": true,
+		},
+	})
+	s.state.Unlock()
+
+	// Start the manager, this is where renames happen.
+	s.manager(c)
+
+	// Check that "core-support" connection got renamed.
+	s.state.Lock()
+	var conns map[string]interface{}
+	err := s.state.Get("conns", &conns)
+	s.state.Unlock()
+	c.Assert(err, IsNil)
+	c.Assert(conns, DeepEquals, map[string]interface{}{
+		"core:core-support-plug core:core-support": map[string]interface{}{
+			"interface": "core-support", "auto": true,
+		},
+		"snap:unrelated core:unrelated": map[string]interface{}{
+			"interface": "unrelated", "auto": true,
+		},
+	})
+}
+
 // Test that "network-bind" and "core-support" plugs are renamed to
 // "network-bind-plug" and "core-support-plug" in order not to clash with slots
 // with the same names.