refactor(protocol): share the echo acknowledgement delay

The client's round-trip correction copied the daemon's 50 ms echo acknowledgement delay as a separate literal. Both now use protocol.EchoAckDelay.

commit: 8442b743fe08c946e327593ebe8546e05d2525a3
author: brice · 14d ago · 2026-10-08 06:01 UTC
parent: 706193c
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email

3 files · +12 -9

M internal/protocol/session.go +6 -0


@@ -229,6 +229,12 @@ func (c ViewContext) Validate() error {
229	229		return domain.ValidatePaneStableID(c.FocusedPaneID)
230	230		}
231	231
	232	+	// EchoAckDelay is how long sequenced input must have been applied before the
	233	+	// daemon acknowledges it in Output.Echo. Like mosh's ECHO_TIMEOUT, it gives the
	234	+	// PTY time to echo the input, so the screen published with the acknowledgement
	235	+	// already contains that echo. Clients remove it from round-trip samples.
	236	+	const EchoAckDelay = 50 * time.Millisecond
	237	+
232	238		type Output struct {
233	239		Epoch uint64
234	240		Base uint64


@@ -229,6 +229,12 @@ func (c ViewContext) Validate() error {
229	return domain.ValidatePaneStableID(c.FocusedPaneID)	229		return domain.ValidatePaneStableID(c.FocusedPaneID)
230	}	230		}
231		231
		232	+	// EchoAckDelay is how long sequenced input must have been applied before the
		233	+	// daemon acknowledges it in Output.Echo. Like mosh's ECHO_TIMEOUT, it gives the
		234	+	// PTY time to echo the input, so the screen published with the acknowledgement
		235	+	// already contains that echo. Clients remove it from round-trip samples.
		236	+	const EchoAckDelay = 50 * time.Millisecond
		237	+
232	type Output struct {	238		type Output struct {
233	Epoch uint64	239		Epoch uint64
234	Base uint64	240		Base uint64

M internal/usecase/client/predictive_echo.go +3 -4


@@ -47,10 +47,9 @@ const (
47	47		echoGlitchRepairCount = 10
48	48		echoGlitchRepairMinInterval = 150 * time.Millisecond
49	49
50		-	// echoServerDelay is the daemon's echo acknowledgement delay
51		-	// (usecase/daemon echoAckDelay). It is removed from each round-trip
52		-	// sample so the thresholds compare network time, as mosh's SRTT does.
53		-	echoServerDelay = 50 * time.Millisecond
	50	+	// echoServerDelay is removed from each round-trip sample so the
	51	+	// thresholds compare network time, as mosh's SRTT does.
	52	+	echoServerDelay = protocol.EchoAckDelay
54	53
55	54		// maxEchoSent bounds the send-time history used for round-trip samples.
56	55		maxEchoSent = 256

 	echoGlitchRepairCount       = 10
 	echoGlitchRepairMinInterval = 150 * time.Millisecond
-	// echoServerDelay is the daemon's echo acknowledgement delay
+	// echoServerDelay is removed from each round-trip sample so the
-	// (usecase/daemon echoAckDelay). It is removed from each round-trip
+	// thresholds compare network time, as mosh's SRTT does.
-	// sample so the thresholds compare network time, as mosh's SRTT does.
+	echoServerDelay = protocol.EchoAckDelay
-	echoServerDelay = 50 * time.Millisecond
 	// maxEchoSent bounds the send-time history used for round-trip samples.
 	maxEchoSent = 256

M internal/usecase/daemon/echo_ack.go +3 -5


@@ -5,13 +5,11 @@ import (
5	5		"time"
6	6
7	7		"github.com/bnema/vev/internal/ports"
	8	+	"github.com/bnema/vev/internal/protocol"
8	9		)
9	10
10		-	// echoAckDelay is how long sequenced input must have been applied before the
11		-	// daemon acknowledges it in Output.Echo. Like mosh's ECHO_TIMEOUT, it gives the
12		-	// PTY time to echo the input, so the screen published with the acknowledgement
13		-	// already contains whatever echo the input produced.
14		-	const echoAckDelay = 50 * time.Millisecond
	11	+	// echoAckDelay is the protocol's echo acknowledgement delay.
	12	+	const echoAckDelay = protocol.EchoAckDelay
15	13
16	14		// maxPendingEchoes bounds the per-attachment input history. Acknowledgements
17	15		// are cumulative, so dropping the oldest entry only delays its confirmation to

 	"time"
 	"github.com/bnema/vev/internal/ports"
+	"github.com/bnema/vev/internal/protocol"
 )
-// echoAckDelay is how long sequenced input must have been applied before the
+// echoAckDelay is the protocol's echo acknowledgement delay.
-// daemon acknowledges it in Output.Echo. Like mosh's ECHO_TIMEOUT, it gives the
+const echoAckDelay = protocol.EchoAckDelay
-// PTY time to echo the input, so the screen published with the acknowledgement
-// already contains whatever echo the input produced.
-const echoAckDelay = 50 * time.Millisecond
 // maxPendingEchoes bounds the per-attachment input history. Acknowledgements
 // are cumulative, so dropping the oldest entry only delays its confirmation to