Remove state path handling from commands

The Local backend is now responsible for handling the paths to the local
state files, since they are dependent on the current environment.

command/meta_backend.go

@@ -72,24 +72,6 @@ func (m *Meta) Backend(opts *BackendOpts) (backend.Enhanced, error) {
 		opts = &BackendOpts{}
 	}
 
-	// Setup the local state paths
-	statePath := m.statePath
-	stateOutPath := m.stateOutPath
-	backupPath := m.backupPath
-	if statePath == "" {
-		statePath = DefaultStateFilename
-	}
-	if stateOutPath == "" {
-		stateOutPath = statePath
-	}
-	if backupPath == "" {
-		backupPath = stateOutPath + DefaultBackupExtension
-	}
-	if backupPath == "-" {
-		// The local backend expects an empty string for not taking backups.
-		backupPath = ""
-	}
-
 	// Initialize a backend from the config unless we're forcing a purely
 	// local operation.
 	var b backend.Backend
@@ -114,9 +96,9 @@ func (m *Meta) Backend(opts *BackendOpts) (backend.Enhanced, error) {
 	cliOpts := &backend.CLIOpts{
 		CLI:             m.Ui,
 		CLIColor:        m.Colorize(),
-		StatePath:       statePath,
+		StatePath:       m.statePath,
-		StateOutPath:    stateOutPath,
+		StateOutPath:    m.stateOutPath,
-		StateBackupPath: backupPath,
+		StateBackupPath: m.backupPath,
 		ContextOpts:     m.contextOpts(),
 		Input:           m.Input(),
 		Validation:      true,

command/state_meta.go

@@ -36,12 +36,16 @@ func (c *StateMeta) State(m *Meta) (state.State, error) {
 		panic(err)
 	}
 	localB := localRaw.(*backendlocal.Local)
+	_, stateOutPath, _, err := localB.StatePaths()
+	if err != nil {
+		return nil, err
+	}
 
 	// Determine the backup path. stateOutPath is set to the resulting
 	// file where state is written (cached in the case of remote state)
 	backupPath := fmt.Sprintf(
 		"%s.%d%s",
-		localB.StateOutPath,
+		stateOutPath,
 		time.Now().UTC().Unix(),
 		DefaultBackupExtension)