fix incorrect current state in local backend

Forgot to remove the currentState field, which was not always set. The
current state should always just be read from the environment file.

Always return the default state name when we can't determine the state.

backend/local/backend.go

@@ -55,10 +55,6 @@ type Local struct {
 
 	// we only want to create a single instance of the local state
 	state state.State
-	// the name of the current state
-	currentState string
-
-	// ContextOpts are the base context options to set when initializing a
 	// Terraform context. Many of these will be overridden or merged by
 	// Operation. See Operation for more details.
 	ContextOpts *terraform.ContextOpts
@@ -135,31 +131,37 @@ func (b *Local) States() ([]string, string, error) {
 	// the listing always start with "default"
 	envs := []string{backend.DefaultStateName}
 
-	current := b.currentState
-	if current == "" {
-		name, err := b.currentStateName()
-		if err != nil {
-			return nil, "", err
-		}
-		current = name
+	current, err := b.currentStateName()
+	if err != nil {
+		return nil, "", err
 	}
 
 	entries, err := ioutil.ReadDir(filepath.Join(b.workingDir, DefaultEnvDir))
 	// no error if there's no envs configured
 	if os.IsNotExist(err) {
-		return envs, current, nil
+		return envs, backend.DefaultStateName, nil
 	}
 	if err != nil {
 		return nil, "", err
 	}
 
+	currentExists := false
 	var listed []string
 	for _, entry := range entries {
 		if entry.IsDir() {
-			listed = append(listed, filepath.Base(entry.Name()))
+			name := filepath.Base(entry.Name())
+			if name == current {
+				currentExists = true
+			}
+			listed = append(listed, name)
 		}
 	}
 
+	// current was out of sync for some reason, so return defualt
+	if !currentExists {
+		current = backend.DefaultStateName
+	}
+
 	sort.Strings(listed)
 	envs = append(envs, listed...)
 
@@ -254,8 +256,6 @@ func (b *Local) ChangeState(name string) error {
 		return err
 	}
 
-	b.currentState = name
-
 	// remove the current state so it's reloaded on the next call to State
 	b.state = nil
 
@@ -421,7 +421,7 @@ func (b *Local) statePath() (string, error) {
 	path := DefaultStateFilename
 
 	if current != backend.DefaultStateName && current != "" {
-		path = filepath.Join(b.workingDir, DefaultEnvDir, b.currentState, DefaultStateFilename)
+		path = filepath.Join(b.workingDir, DefaultEnvDir, current, DefaultStateFilename)
 	}
 	return path, nil
 }