pkg/edit: Fix race conditions.

pkg/cli/addons/histwalk/histwalk.go

@@ -66,7 +66,7 @@ func Start(app cli.App, cfg Config) {
 	if cfg.Binding == nil {
 		cfg.Binding = cli.DummyHandler{}
 	}
-	cursor := histutil.NewDedupCursor(cfg.Store.Cursor(cfg.Prefix))
+	cursor := cfg.Store.Cursor(cfg.Prefix)
 	cursor.Prev()
 	_, err := cursor.Get()
 	if err != nil {

pkg/cli/addons/histwalk/histwalk_test.go

@@ -21,8 +21,8 @@ func TestHistWalk(t *testing.T) {
 
 	getCfg := func() Config {
 		store := histutil.NewMemStore(
-			// 0       1        2         3        4         5
-			"echo", "ls -l", "echo a", "ls -a", "echo a", "ls -a")
+			// 0       1        2         3       4         5
+			"echo", "ls -l", "echo a", "echo", "echo a", "ls -a")
 		return Config{
 			Store:  store,
 			Prefix: "ls",
@@ -45,7 +45,6 @@ func TestHistWalk(t *testing.T) {
 	f.TTY.TestBuffer(t, buf5)
 
 	f.TTY.Inject(term.K(ui.Up))
-	// Skips item #3 as it is a duplicate.
 	buf1 := f.MakeBuffer(
 		"ls -l", Styles,
 		"  ___", term.DotHere, "\n",

pkg/edit/hist_store.go

@@ -35,7 +35,7 @@ func (s *histStore) AllCmds() ([]store.Cmd, error) {
 func (s *histStore) Cursor(prefix string) histutil.Cursor {
 	s.m.Lock()
 	defer s.m.Unlock()
-	return s.hs.Cursor(prefix)
+	return cursor{&s.m, histutil.NewDedupCursor(s.hs.Cursor(prefix))}
 }
 
 func (s *histStore) FastForward() error {
@@ -45,3 +45,26 @@ func (s *histStore) FastForward() error {
 	s.hs = hs
 	return err
 }
+
+type cursor struct {
+	m *sync.Mutex
+	c histutil.Cursor
+}
+
+func (c cursor) Prev() {
+	c.m.Lock()
+	defer c.m.Unlock()
+	c.c.Prev()
+}
+
+func (c cursor) Next() {
+	c.m.Lock()
+	defer c.m.Unlock()
+	c.c.Next()
+}
+
+func (c cursor) Get() (store.Cmd, error) {
+	c.m.Lock()
+	defer c.m.Unlock()
+	return c.c.Get()
+}