Use project for host capabilities

internal/core/basis.go

@@ -257,14 +257,6 @@ func (b *Basis) Host() (host core.Host, err error) {
 		return nil, fmt.Errorf("failed to detect host plugin for current platform")
 	}
 
-	if s, ok := result.(core.Seeder); ok {
-		if err = s.Seed(b.statebag); err != nil {
-			return nil, err
-		}
-	} else {
-		return nil, fmt.Errorf("host plugin does not support seeder interface")
-	}
-
 	b.logger.Info("host detection complete",
 		"name", result_name)
 

internal/core/project.go

@@ -114,7 +114,20 @@ func (p *Project) DefaultPrivateKey() (path string, err error) {
 
 // Host implements core.Project
 func (p *Project) Host() (host core.Host, err error) {
-	return p.basis.Host()
+	if host, err = p.basis.Host(); err != nil {
+		return
+	}
+	if s, ok := host.(core.Seeder); ok {
+		list, err := s.Seeds()
+		if err != nil {
+			return nil, err
+		}
+		list = append(list, p)
+		if err = s.Seed(list...); err != nil {
+			return nil, err
+		}
+	}
+	return
 }
 
 // MachineIndex implements core.Project

plugins/commands/serve/service/host_service.rb

@@ -12,7 +12,7 @@ module VagrantPlugins
           default_args = [
             # Always get the state bag for host capabilities
             SDK::FuncSpec::Value.new(
-              type: "hashicorp.vagrant.sdk.Args.StateBag",
+              type: "hashicorp.vagrant.sdk.Args.Project",
               name: "",
             ),
           ]