Merge pull request #12818 from hashicorp/b-legacy

command: use backendinit instead of initializing legacy directly

command/meta_backend.go

@@ -23,7 +23,6 @@ import (
 	"github.com/hashicorp/terraform/terraform"
 	"github.com/mitchellh/mapstructure"
 
-	backendlegacy "github.com/hashicorp/terraform/backend/legacy"
 	backendlocal "github.com/hashicorp/terraform/backend/local"
 )
 
@@ -1325,8 +1324,12 @@ func (m *Meta) backendInitFromLegacy(s *terraform.RemoteState) (backend.Backend,
 	}
 	config := terraform.NewResourceConfig(rawC)
 
-	// Initialize the legacy remote backend
-	b := &backendlegacy.Backend{Type: s.Type}
+	// Get the backend
+	f := backendinit.Backend(s.Type)
+	if f == nil {
+		return nil, fmt.Errorf(strings.TrimSpace(errBackendLegacyUnknown), s.Type)
+	}
+	b := f()
 
 	// Configure
 	if err := b.Configure(config); err != nil {
@@ -1381,7 +1384,7 @@ If fixing these errors requires changing your remote state configuration,
 you must switch your configuration to the new remote backend configuration.
 You can learn more about remote backends at the URL below:
 
-TODO: URL
+https://www.terraform.io/docs/backends/index.html
 
 The error(s) configuring the legacy remote state:
 
@@ -1391,7 +1394,7 @@ The error(s) configuring the legacy remote state:
 const errBackendLegacyUnknown = `
 The legacy remote state type %q could not be found.
 
-Terraform 0.9.0 shipped with backwards compatible for all built-in
+Terraform 0.9.0 shipped with backwards compatibility for all built-in
 legacy remote state types. This error may mean that you were using a
 custom Terraform build that perhaps supported a different type of
 remote state.