Validate admin targets before actions

admin.go

@@ -169,7 +169,9 @@ func (b *Barnard) AdminItemKeyPress(ui *uiterm.Ui, tree *uiterm.Tree, item uiter
 	if !ok || admin.action == nil {
 		return
 	}
-	admin.action()
+	if !b.withValidAdminTargets(admin.action) {
+		b.AddOutputLine("Admin: action target is no longer available")
+	}
 	b.UiAdmin.Rebuild()
 	b.Ui.Refresh()
 }
@@ -549,13 +551,37 @@ func (b *Barnard) handleAdminPrompt(text string) bool {
 	}
 	prompt := b.pendingAdminPrompt
 	b.pendingAdminPrompt = nil
-	prompt.action(strings.TrimSpace(text))
+	if !b.withValidAdminTargets(func() { prompt.action(strings.TrimSpace(text)) }) {
+		b.AddOutputLine("Admin: action target is no longer available")
+	}
 	if b.Client != nil && b.Client.Self != nil {
 		b.UpdateInputStatus(fmt.Sprintf("[%s]", b.Client.Self.Channel.Name))
 	}
 	return true
 }
 
+// withValidAdminTargets runs an action only while its selected targets are
+// still members of the current connection. Menu actions can outlive server
+// removal events while a prompt is open.
+func (b *Barnard) withValidAdminTargets(action func()) bool {
+	if b.Client == nil {
+		return false
+	}
+	valid := true
+	b.Client.Do(func() {
+		if u := b.adminTargetUser; u != nil && b.Client.Users[u.Session] != u {
+			valid = false
+		}
+		if ch := b.adminTargetChan; ch != nil && b.Client.Channels[ch.ID] != ch {
+			valid = false
+		}
+		if valid {
+			action()
+		}
+	})
+	return valid
+}
+
 func (b *Barnard) CommandAdmin(ui *uiterm.Ui, cmd string) {
 	b.executeAdminCommand(cmd)
 }

admin_target_test.go

@@ -0,0 +1,30 @@
+package main
+
+import (
+	"testing"
+
+	"git.stormux.org/storm/barnard/gumble/gumble"
+)
+
+func TestAdminActionRejectsRemovedTarget(t *testing.T) {
+	user := &gumble.User{Session: 1}
+	client := &gumble.Client{Users: gumble.Users{1: user}, Channels: gumble.Channels{}}
+	b := &Barnard{Client: client, adminTargetUser: user}
+	called := false
+	if !b.withValidAdminTargets(func() { called = true }) || !called {
+		t.Fatal("current admin target was rejected")
+	}
+	delete(client.Users, user.Session)
+	called = false
+	if b.withValidAdminTargets(func() { called = true }) || called {
+		t.Fatal("removed admin target was allowed to execute")
+	}
+}
+
+func TestAdminActionRejectsReplacedChannelTarget(t *testing.T) {
+	channel := &gumble.Channel{ID: 2}
+	b := &Barnard{Client: &gumble.Client{Channels: gumble.Channels{2: &gumble.Channel{ID: 2}}}, adminTargetChan: channel}
+	if b.withValidAdminTargets(func() {}) {
+		t.Fatal("replaced channel target was allowed to execute")
+	}
+}