Refuse a PRIVMSG or NOTICE whose body or meta has the wrong type (closes #245)

Over the HTTP API, a PRIVMSG or NOTICE body was checked only by
decoding it into a list of strings. JSON null decodes into an empty
string there, and meta was not checked at all, so a null line, or a
meta that is not an object, reached every recipient.

handlePrivmsg now answers 400 invalid request body, before anything
else, when body is present and is not an array of strings, or meta is
present and is not an object. The check returns the lines it accepted,
and the empty-body check counts those, so body is decoded once. A
missing or empty body still gets ERR_NOTEXTTOSEND. README.md says so.

Model: opus-5-5

internal/cli/app.go

@@ -402,10 +402,16 @@ func (a *App) cmdQuery(nick string) {
 	a.mu.Lock()
 	a.target = nick
 	myNick := a.nick
+	connected := a.connected
 	a.mu.Unlock()
 
+	connStatus := "disconnected"
+	if connected {
+		connStatus = "connected"
+	}
+
 	a.ui.SwitchToBuffer(nick)
-	a.ui.SetStatus(myNick, nick, "connected")
+	a.ui.SetStatus(myNick, nick, connStatus)
 }
 
 func (a *App) cmdTopic(args string) {

internal/cli/app_internal_test.go

@@ -23,6 +23,13 @@ const (
 	testText      = "hello"
 )
 
+// What the status bar shows while the client is connected, and
+// while it is not.
+const (
+	statusConnected    = "[connected]"
+	statusDisconnected = "[disconnected]"
+)
+
 // eventLoopTimeout is how long a test waits for a typed line to
 // be handled, for the welcome lines, for the UI to stop, for a poll
 // or for a poll loop to end, before it fails.
@@ -361,6 +368,46 @@ func TestWindowConnectionState(t *testing.T) {
 	}
 }
 
+// TestQueryConnectionState checks that typing /query bob leaves the
+// status bar showing [connected] only while the client is connected,
+// and [disconnected] otherwise.
+func TestQueryConnectionState(t *testing.T) {
+	t.Parallel()
+
+	const line = "/query " + testOtherNick
+
+	tests := []struct {
+		name      string
+		connected bool
+		want      string
+	}{
+		{name: "not connected", connected: false, want: statusDisconnected},
+		{name: "connected", connected: true, want: statusConnected},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+
+			app := &App{ui: NewUI(), nick: testNick, connected: test.connected}
+			handled := handledLines(app)
+			runUI(t, app.ui)
+
+			for _, r := range line {
+				app.ui.app.QueueEvent(tcell.NewEventKey(tcell.KeyRune, r, tcell.ModNone))
+			}
+
+			app.ui.app.QueueEvent(tcell.NewEventKey(tcell.KeyEnter, 0, tcell.ModNone))
+			waitHandled(t, handled, line)
+
+			status := statusBarText(app.ui)
+			if !strings.Contains(status, test.want) {
+				t.Fatalf("status bar is %q, want it to show %s", status, test.want)
+			}
+		})
+	}
+}
+
 // TestEventLoopKeepsRunning sends Alt and 1, then a typed line and
 // Enter, to a running UI. It checks that both are handled, so the
 // event loop did not stop on either.