overlord/ifacestate: remove core-support-plug on startup

This patch ensures that the "core" snap doesn't have the
core-support-plug even if one was defined statically in snap.yaml.

This is just a test of the upcoming real removal.

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>

overlord/ifacestate/helpers.go

@@ -51,6 +51,9 @@ func (m *InterfaceManager) initialize(extraInterfaces []interfaces.Interface, ex
 	if err := m.renameCorePlugConnection(); err != nil {
 		return err
 	}
+	if err := m.removeCoreSupportPlug(); err != nil {
+		return err
+	}
 	if err := removeStaleConnections(m.state); err != nil {
 		return err
 	}
@@ -198,6 +201,16 @@ func (m *InterfaceManager) renameCorePlugConnection() error {
 	return nil
 }
 
+// removeCoreSupportPlug removes the "core-support-plug" from the core snap.
+// This is done in anticipation of https://github.com/snapcore/core/pull/92
+func (m *InterfaceManager) removeCoreSupportPlug() error {
+	var err error
+	if m.repo.Plug("core", "core-support-plug") != nil {
+		err = m.repo.RemovePlug("core", "core-support-plug")
+	}
+	return err
+}
+
 // removeStaleConnections removes stale connections left by some older versions of snapd.
 // Connection is considered stale if the snap on either end of the connection doesn't exist anymore.
 // XXX: this code should eventually go away.

overlord/ifacestate/ifacestate_test.go

@@ -2426,7 +2426,8 @@ func (s *interfaceManagerSuite) TestCoreConnectionsRenamed(c *C) {
 
 // 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.
+// with the same names. This test also shows how core-support-plug is removed
+// after being renamed.
 func (s *interfaceManagerSuite) TestAutomaticCorePlugsRenamed(c *C) {
 	s.mockSnap(c, coreSnapYaml+`
 plugs:
@@ -2438,12 +2439,13 @@ plugs:
 	// old plugs are gone
 	c.Assert(mgr.Repository().Plug("core", "network-bind"), IsNil)
 	c.Assert(mgr.Repository().Plug("core", "core-support"), IsNil)
-	// new plugs are present
-	c.Assert(mgr.Repository().Plug("core", "network-bind-plug"), Not(IsNil))
-	c.Assert(mgr.Repository().Plug("core", "core-support-plug"), Not(IsNil))
+	// new plugs are present (well, one of them)
+	c.Assert(mgr.Repository().Plug("core", "network-bind-plug"), NotNil)
+	// The core support plug is now removed from core.
+	c.Assert(mgr.Repository().Plug("core", "core-support-plug"), IsNil)
 	// slots are present and unchanged
-	c.Assert(mgr.Repository().Slot("core", "network-bind"), Not(IsNil))
-	c.Assert(mgr.Repository().Slot("core", "core-support"), Not(IsNil))
+	c.Assert(mgr.Repository().Slot("core", "network-bind"), NotNil)
+	c.Assert(mgr.Repository().Slot("core", "core-support"), NotNil)
 }
 
 func (s *interfaceManagerSuite) TestAutoConnectDuringCoreTransition(c *C) {