fix(icom): a set whose acknowledgement is lost is sent once more

Extends to frequency and mode what PTT already had. A missing FB is not a
missing command: the rig acts on the frame as it decodes it, and what
expires is our wait for the answer, on a bus shared with the rig's own
transceive updates. JTDX in "Split: Fake It" moves the dial and the mode
immediately before every key-down, so those acks queue behind each other.

Losing one is fatal to the client rather than merely untidy: rigctld answers
RPRT -9, JTDX reads that as losing rig control and tears the connection down
mid-over. An operator's log shows three set_freq failures and one set_mode,
each followed within 300 ms by a fresh rigctld client -- and shows the PTT
resend rescuing an over that would otherwise have ended there.

Opt-in per caller rather than folded into exec: only a command that says
"be in this state" can be repeated safely, and a relative one must never
come through here.

The acknowledgement loss itself is still unexplained. Every failure in that
log is preceded by a state read reporting SSB on a rig in DATA, which points
at CI-V frame desync rather than a slow rig, and needs a trace to pin down.

changelog.json

@@ -1,4 +1,18 @@
 [
+  {
+    "version": "0.25.9",
+    "date": "",
+    "en": [
+      "The band/mode matrix colours can be chosen in Appearance, starting from the ones your theme already paints. Its legend is translated too.",
+      "TCI sharing: a refused un-key no longer leaves the rig stuck transmitting, and PTT is dropped if the client dies mid-over.",
+      "Icom: a frequency or mode change whose acknowledgement is lost is sent again, like PTT — losing one made JTDX drop the radio."
+    ],
+    "fr": [
+      "Les couleurs de la matrice bandes/modes se choisissent dans Apparence, à partir de celles du thème. Sa légende est traduite aussi.",
+      "Partage TCI : un retour en réception refusé ne laisse plus le poste bloqué en émission, et le PTT retombe si le logiciel meurt.",
+      "Icom : un changement de fréquence ou de mode dont l’accusé se perd est renvoyé, comme le PTT — en perdre un faisait lâcher JTDX."
+    ]
+  },
   {
     "version": "0.25.8",
     "date": "",

internal/cat/icomserial.go

@@ -514,7 +514,8 @@ func (b *IcomSerial) SetFrequency(hz int64) error {
 		return fmt.Errorf("invalid frequency")
 	}
 	b.lastSetFreq, b.lastSetFreqAt = hz, time.Now()
-	return b.exec(append([]byte{civ.CmdSetFreq}, civ.FreqToBCD(hz)...)...)
+	return b.execIdempotent(fmt.Sprintf("set frequency %d Hz", hz),
+		append([]byte{civ.CmdSetFreq}, civ.FreqToBCD(hz)...)...)
 }
 
 func (b *IcomSerial) SetMode(mode string) error {
@@ -524,7 +525,7 @@ func (b *IcomSerial) SetMode(mode string) error {
 	}
 	// Set the base mode (keeping the rig's current filter by sending only the
 	// mode byte), then set the data-mode flag for digital modes.
-	if err := b.exec(civ.CmdSetMode, code); err != nil {
+	if err := b.execIdempotent("set mode "+mode, civ.CmdSetMode, code); err != nil {
 		return err
 	}
 	dataByte := byte(0)
@@ -532,7 +533,7 @@ func (b *IcomSerial) SetMode(mode string) error {
 		dataByte = 1
 	}
 	// Filter 0x01 (FIL1) is the conventional default for the data-mode set.
-	_ = b.exec(civ.CmdExtra, civ.SubDataMode, dataByte, 0x01)
+	_ = b.execIdempotent("set data mode", civ.CmdExtra, civ.SubDataMode, dataByte, 0x01)
 	return nil
 }
 
@@ -542,31 +543,38 @@ func (b *IcomSerial) SetMode(mode string) error {
 // a formatted string so callers can tell the two apart.
 var errIcomAckLost = errors.New("icom: timeout waiting for response")
 
-// SetPTT keys or unkeys the transmitter (CI-V 0x1C 0x00), retrying ONCE when the
+// execIdempotent runs a SET command and sends it ONCE MORE if the
 // acknowledgement is lost.
 //
 // A missing FB is not a missing command — the rig acts on the frame as soon as it
 // decodes it, and what expires is our wait for the answer on a bus shared with
 // the rig's own transceive updates. JTDX in "Split Operating: Fake It" moves the
-// dial immediately before every key-down, so the PTT ack queues behind that
-// traffic, and one lost ack was fatal: rigctld answered RPRT -9, JTDX read that
-// as losing rig control and tore the connection down mid-over, reopening it a
-// moment later (an operator's log shows exactly that, twice, a new rigctld client
-// within 300 ms of each failure). The same session over TCI never failed, because
-// TCI carries no CI-V and needs no Fake It.
+// dial and the mode immediately before every key-down, so those acks queue behind
+// each other, and losing one was fatal: rigctld answers RPRT -9, JTDX reads that
+// as losing rig control and tears the connection down mid-over. An operator's log
+// shows it happening on set_ptt, on set_freq and on set_mode alike, each failure
+// followed within 300 ms by a fresh rigctld client — and shows this resend
+// rescuing a PTT that would otherwise have ended the over.
 //
-// Re-sending is safe: asking for a state the rig is already in changes nothing.
+// Only for commands that say "be in this state": re-sending one changes nothing
+// if the first arrived. A relative or incremental command must not come through
+// here, which is why this is opt-in per caller rather than folded into exec.
+func (b *IcomSerial) execIdempotent(what string, payload ...byte) error {
+	err := b.exec(payload...)
+	if err == nil || !errors.Is(err, errIcomAckLost) {
+		return err
+	}
+	applog.Printf("icom: %s — no acknowledgement in %s, sending it once more", what, icomCmdTimeout)
+	return b.exec(payload...)
+}
+
+// SetPTT keys or unkeys the transmitter (CI-V 0x1C 0x00).
 func (b *IcomSerial) SetPTT(on bool) error {
 	state := byte(0)
 	if on {
 		state = 1
 	}
-	err := b.exec(civ.CmdPTT, civ.SubPTT, state)
-	if err == nil || !errors.Is(err, errIcomAckLost) {
-		return err
-	}
-	applog.Printf("icom: PTT %v — no acknowledgement in %s, sending it once more", on, icomCmdTimeout)
-	return b.exec(civ.CmdPTT, civ.SubPTT, state)
+	return b.execIdempotent(fmt.Sprintf("PTT %v", on), civ.CmdPTT, civ.SubPTT, state)
 }
 
 // SetPower turns the transceiver on or off (CI-V 0x18). Power-ON is prefixed with