fix(udp): two copies of MSHV shared one dial frequency

FT8 decodes made on 14.095 were labelled 2190 m. That band is 135.7-137.8 kHz, and every affected decode's audio offset plus 136.1 kHz lands inside it — while the ones shown with no band at all land just above 137.8. The decodes were being stamped with another instance's dial. WSJT-X refuses to start a second instance without --rig-name, so its ids differ and keying on the id worked. MSHV has no such rule: both copies call themselves 'MSHV', so the LF instance's Status overwrote the HF one's dial, T/R period and mode. Instances are now identified by their sending socket as well as their name — the socket is stable for as long as the program runs, which is exactly the lifetime this has to hold over. A second application claiming an id already in use is shown as 'MSHV #2' and says so in the log, so the decodes panel can still split them. This also fixes replies: a Reply was addressed to whichever copy sent Status last, which on a two-instance station is a coin toss.
2026-08-24 21:38:30 +02:00
parent bd4f1b2325
commit d8064cc426
3 changed files with 118 additions and 14 deletions
@@ -0,0 +1,52 @@
+package udp
+
+import (
+	"net"
+	"testing"
+)
+
+// Two copies of MSHV call themselves "MSHV". WSJT-X refuses to start a second
+// instance without --rig-name, so its ids differ; MSHV has no such rule, and
+// everything a decode needs — the dial frequency, the T/R period, the mode —
+// used to be filed under the id alone.
+//
+// The consequence was reported from a real station: the second copy, on LF,
+// overwrote the dial of the first, and FT8 decodes made on 14.095 came out
+// labelled 2190 m — which is 136 kHz plus an audio offset, to the hertz.
+func TestSameProgramIDFromTwoAddressesAreTwoInstances(t *testing.T) {
+	s := &Server{}
+	a := &net.UDPAddr{IP: net.IPv4(127, 0, 0, 1), Port: 2237}
+	b := &net.UDPAddr{IP: net.IPv4(127, 0, 0, 1), Port: 2238}
+
+	first := s.instanceLabel("MSHV", a)
+	second := s.instanceLabel("MSHV", b)
+	if first == second {
+		t.Fatalf("two applications on different sockets share the label %q", first)
+	}
+	if first != "MSHV" {
+		t.Fatalf("the first instance should keep the plain id, got %q", first)
+	}
+
+	// Stable: the same socket must keep its name for as long as it runs, or the
+	// decodes panel would grow a new column every time a packet arrived.
+	if again := s.instanceLabel("MSHV", a); again != first {
+		t.Fatalf("label changed for the same address: %q then %q", first, again)
+	}
+	if again := s.instanceLabel("MSHV", b); again != second {
+		t.Fatalf("label changed for the same address: %q then %q", second, again)
+	}
+}
+
+// Distinct ids stay distinct without decoration — a station running WSJT-X and
+// MSHV should not see either renamed.
+func TestDifferentProgramIDsAreLeftAlone(t *testing.T) {
+	s := &Server{}
+	a := &net.UDPAddr{IP: net.IPv4(127, 0, 0, 1), Port: 2237}
+	b := &net.UDPAddr{IP: net.IPv4(127, 0, 0, 1), Port: 2238}
+	if got := s.instanceLabel("WSJT-X", a); got != "WSJT-X" {
+		t.Fatalf("WSJT-X was renamed to %q", got)
+	}
+	if got := s.instanceLabel("MSHV", b); got != "MSHV" {
+		t.Fatalf("MSHV was renamed to %q", got)
+	}
+}