fix(ui): guard tree collapse toggle against a nil root (#4257)

internal/ui/tree.go

@@ -111,7 +111,12 @@ func (*Tree) noopCmd(evt *tcell.EventKey) *tcell.EventKey {
 
 func (t *Tree) toggleCollapseCmd(*tcell.EventKey) *tcell.EventKey {
 	t.expandNodes = !t.expandNodes
-	t.GetRoot().Walk(func(node, parent *tview.TreeNode) bool {
+	// The root is populated asynchronously and may not be set yet.
+	root := t.GetRoot()
+	if root == nil {
+		return nil
+	}
+	root.Walk(func(node, parent *tview.TreeNode) bool {
 		if parent != nil {
 			node.SetExpanded(t.expandNodes)
 		}

internal/ui/tree_test.go

@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright Authors of K9s
+
+package ui_test
+
+import (
+	"testing"
+
+	"github.com/derailed/k9s/internal/ui"
+	"github.com/derailed/tcell/v2"
+	"github.com/derailed/tview"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestTreeToggleCollapse(t *testing.T) {
+	uu := map[string]struct {
+		root *tview.TreeNode
+	}{
+		"no-root": {},
+		"root": {
+			root: tview.NewTreeNode("root").AddChild(tview.NewTreeNode("child")),
+		},
+	}
+
+	for k := range uu {
+		u := uu[k]
+		t.Run(k, func(t *testing.T) {
+			v := ui.NewTree()
+			v.BindKeys()
+			if u.root != nil {
+				v.SetRoot(u.root)
+			}
+			a, ok := v.Actions().Get(ui.KeyX)
+			require.True(t, ok)
+
+			assert.NotPanics(t, func() {
+				a.Action(tcell.NewEventKey(tcell.KeyRune, 'x', tcell.ModNone))
+			})
+			assert.False(t, v.ExpandNodes())
+			if u.root != nil {
+				assert.False(t, u.root.GetChildren()[0].IsExpanded())
+			}
+		})
+	}
+}

internal/view/xray.go

@@ -510,7 +510,12 @@ func (x *Xray) gotoCmd(*tcell.EventKey) *tcell.EventKey {
 			x.Start()
 		}
 		x.CmdBuff().SetActive(false)
-		x.GetRoot().ExpandAll()
+		// The root is populated asynchronously and may not be set yet.
+		root := x.GetRoot()
+		if root == nil {
+			return nil
+		}
+		root.ExpandAll()
 
 		return nil
 	}

internal/view/xray_int_test.go

@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright Authors of K9s
+
+package view
+
+import (
+	"testing"
+
+	"github.com/derailed/k9s/internal/client"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestXrayGotoCmdBeforeTreeLoaded(t *testing.T) {
+	v, ok := NewXray(client.NewGVR("deployments")).(*Xray)
+	assert.True(t, ok)
+	v.CmdBuff().SetActive(true)
+
+	assert.NotPanics(t, func() {
+		v.gotoCmd(nil)
+	})
+	assert.False(t, v.CmdBuff().IsActive())
+}