chore: refresh gramsrv public release

internal/mtprotoedge/layer_downgrade_test.go

@@ -0,0 +1,65 @@
+package mtprotoedge
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/gotd/td/bin"
+	"github.com/gotd/td/tg"
+)
+
+// TestConnDowngradedClone verifies the outbound seam downgrades a canonical
+// (227) object to the connection's negotiated layer, is a no-op for 227, and
+// — critically for push fan-out — never mutates the shared input message (one
+// pre-encoded update is reused across many connections of differing layers).
+func TestConnDowngradedClone(t *testing.T) {
+	const (
+		message227CRC = 0x7600b9d3
+		message220CRC = 0xb92f76cf
+	)
+	msg := &tg.Message{
+		ID:      2,
+		FromID:  &tg.PeerUser{UserID: 3},
+		PeerID:  &tg.PeerUser{UserID: 3},
+		Date:    1,
+		Message: "hi",
+	}
+
+	// layer 220: returns a NEW message rewritten to the 220 constructor id,
+	// leaving the shared input untouched (227).
+	enc, err := encodeOutboundMessage(msg)
+	if err != nil {
+		t.Fatalf("encode: %v", err)
+	}
+	c := &Conn{metrics: NopMetrics{}}
+	c.SetClientLayer(220)
+	out := c.downgradedClone(enc)
+
+	if id, _ := (&bin.Buffer{Buf: out.body}).PeekID(); id != message220CRC {
+		t.Fatalf("downgraded id = %#08x, want %#08x", id, message220CRC)
+	}
+	if out.typeID != message220CRC {
+		t.Fatalf("downgraded typeID = %#08x, want %#08x", out.typeID, message220CRC)
+	}
+	// Input must be unmodified — this is what makes shared push fan-out safe.
+	if id, _ := (&bin.Buffer{Buf: enc.body}).PeekID(); id != message227CRC {
+		t.Fatalf("input message was mutated: id now %#08x, want 227 %#08x", id, message227CRC)
+	}
+
+	// Two connections sharing one pre-encoded message get independent results.
+	encShared, _ := encodeOutboundMessage(msg)
+	c220 := &Conn{metrics: NopMetrics{}}
+	c220.SetClientLayer(220)
+	c227 := &Conn{metrics: NopMetrics{}} // ClientLayer() defaults to 227
+	out220 := c220.downgradedClone(encShared)
+	out227 := c227.downgradedClone(encShared)
+	if id, _ := (&bin.Buffer{Buf: out220.body}).PeekID(); id != message220CRC {
+		t.Fatalf("shared->220 id = %#08x, want %#08x", id, message220CRC)
+	}
+	if out227 != encShared {
+		t.Errorf("227 connection should pass the shared message through unchanged (same pointer)")
+	}
+	if !bytes.Equal(encShared.body, out227.body) {
+		t.Errorf("227 passthrough altered bytes")
+	}
+}