4fda349 fix(daemon): lift the copy-scroll step cap once a held backlog is drained · vev

M docs/performance.md +7 -6


@@ -226,12 +226,13 @@ The unadorned live-pane cache stays separate from the displayed copy viewport.
226	226		Neither committed frame is mutated while preparing a candidate; failed output
227	227		cannot publish its viewport metadata. Copy exit refreshes live content.
228	228
229		-	Remote clients request the full output window (`MaxOutputWindow`, 8 frames),
230		-	so the animation keeps moving while acknowledgements are in flight; it stays
231		-	smooth up to about 100 ms of round trip. When the window is full the animation
232		-	holds still instead of piling rows into one frame, then drains the backlog at
233		-	no more than 9 rows per frame once acknowledgements return. A hold longer than
234		-	about one second abandons the scroll. Local scrolling is unchanged.
	229	+	Clients request the full output window (`MaxOutputWindow`, 8 frames), so the
	230	+	animation keeps moving while acknowledgements are in flight; on a remote link
	231	+	it stays smooth up to about 100 ms of round trip. When the window is full the
	232	+	animation holds still instead of piling rows into one frame, then drains the
	233	+	backlog it held at no more than 9 rows per frame; the next scroll eases
	234	+	normally again. A hold longer than about one second abandons the scroll.
	235	+	Local scroll easing is unchanged, since a local window never fills.
235	236		`TestCopyScrollOverDelayedAcks` replays a flick and a sustained scroll over
236	237		0–400 ms acknowledgement delays with windows of 1 and 8 frames; it asserts
237	238		that no frame jumps more than 9 rows and that every requested row is shown,


@@ -226,12 +226,13 @@ The unadorned live-pane cache stays separate from the displayed copy viewport.
226		Neither committed frame is mutated while preparing a candidate; failed output	226		Neither committed frame is mutated while preparing a candidate; failed output
227		cannot publish its viewport metadata. Copy exit refreshes live content.	227		cannot publish its viewport metadata. Copy exit refreshes live content.
228			228
229	-	Remote clients request the full output window (`MaxOutputWindow`, 8 frames),	229	+	Clients request the full output window (`MaxOutputWindow`, 8 frames), so the
230	-	so the animation keeps moving while acknowledgements are in flight; it stays	230	+	animation keeps moving while acknowledgements are in flight; on a remote link
231	-	smooth up to about 100 ms of round trip. When the window is full the animation	231	+	it stays smooth up to about 100 ms of round trip. When the window is full the
232	-	holds still instead of piling rows into one frame, then drains the backlog at	232	+	animation holds still instead of piling rows into one frame, then drains the
233	-	no more than 9 rows per frame once acknowledgements return. A hold longer than	233	+	backlog it held at no more than 9 rows per frame; the next scroll eases
234	-	about one second abandons the scroll. Local scrolling is unchanged.	234	+	normally again. A hold longer than about one second abandons the scroll.
			235	+	Local scroll easing is unchanged, since a local window never fills.
235		`TestCopyScrollOverDelayedAcks` replays a flick and a sustained scroll over	236		`TestCopyScrollOverDelayedAcks` replays a flick and a sustained scroll over
236		0–400 ms acknowledgement delays with windows of 1 and 8 frames; it asserts	237		0–400 ms acknowledgement delays with windows of 1 and 8 frames; it asserts
237		that no frame jumps more than 9 rows and that every requested row is shown,	238		that no frame jumps more than 9 rows and that every requested row is shown,

M internal/usecase/daemon/copy_scroll_animation.go +4 -0


@@ -119,6 +119,10 @@ func (d Daemon) advanceCopyScrollLocked(sess session, ac *attachedClient) (boo
119	119		rt.stopCopyScrollLocked()
120	120		return changed, exit
121	121		}
	122	+	if motion.remaining == 0 {
	123	+	// The held backlog is drained: the next scroll eases freely again.
	124	+	motion.recovering = false
	125	+	}
122	126		}
123	127		if motion.remaining != 0 {
124	128		mode := rt.copyMode


@@ -119,6 +119,10 @@ func (d Daemon) advanceCopyScrollLocked(sess session, ac *attachedClient) (boo
119	rt.stopCopyScrollLocked()	119		rt.stopCopyScrollLocked()
120	return changed, exit	120		return changed, exit
121	}	121		}
		122	+	if motion.remaining == 0 {
		123	+	// The held backlog is drained: the next scroll eases freely again.
		124	+	motion.recovering = false
		125	+	}
122	}	126		}
123	if motion.remaining != 0 {	127		if motion.remaining != 0 {
124	mode := rt.copyMode	128		mode := rt.copyMode

M internal/usecase/daemon/copy_scroll_animation_test.go +22 -3


@@ -136,17 +136,22 @@ func TestCopyScrollReducedMotionAndKeyboardCancellation(t *testing.T) {
136	136
137	137		// TestCopyScrollAnimationFullOutputWindow covers a remote link whose output
138	138		// window is full: the animation holds still, drains the backlog in capped
139		-	// steps once the window reopens, and gives up after about a second of hold.
	139	+	// steps once the window reopens, eases freely again once that backlog is
	140	+	// drained, and gives up after about a second of hold.
140	141		func TestCopyScrollAnimationFullOutputWindow(t *testing.T) {
141	142		tests := []struct {
142	143		name string
143	144		heldFrames int
144	145		reopen bool
145		-	wantMoved int
146		-	wantActive bool
	146	+	// drainThenFlick drains the held backlog, then starts a new 60-row
	147	+	// flick past the tail deadline; wantMoved counts only that flick.
	148	+	drainThenFlick bool
	149	+	wantMoved int
	150	+	wantActive bool
147	151		}{
148	152		{name: "full window holds the viewport", heldFrames: 1, wantMoved: 0, wantActive: true},
149	153		{name: "reopened window drains in capped steps", heldFrames: 1, reopen: true, wantMoved: copyScrollMaxStep, wantActive: true},
	154	+	{name: "drained backlog lifts the cap for the next flick", heldFrames: 1, reopen: true, drainThenFlick: true, wantMoved: 60, wantActive: false},
150	155		{name: "long hold abandons the scroll", heldFrames: copyScrollMaxHeldFrames + 1, wantMoved: 0, wantActive: false},
151	156		}
152	157		for _, tt := range tests {

@@ -178,6 +183,20 @@ func TestCopyScrollAnimationFullOutputWindow(t *testing.T) {
178	183		require.True(t, changed)
179	184		require.False(t, exit)
180	185		}
	186	+	if tt.drainThenFlick {
	187	+	for rt.copyScroll.remaining != 0 {
	188	+	f.ac.ackOutputState(f.ac.output.currentEpoch(), f.ac.output.next)
	189	+	rt.copyScroll.timer.stop()
	190	+	changed, exit := f.d.advanceCopyScrollLocked(f.sess, f.ac)
	191	+	require.True(t, changed)
	192	+	require.False(t, exit)
	193	+	}
	194	+	start = rt.copyMode.ViewportTop
	195	+	rt.copyScroll.remaining = -60
	196	+	changed, exit := f.d.advanceCopyScrollLocked(f.sess, f.ac)
	197	+	require.True(t, changed)
	198	+	require.False(t, exit)
	199	+	}
181	200		require.Equal(t, tt.wantMoved, start-rt.copyMode.ViewportTop)
182	201		require.Equal(t, tt.wantActive, rt.copyScroll.remaining != 0)
183	202		require.Equal(t, tt.wantActive, rt.copyScroll.timer.timer != nil, "the frame timer stays armed only while the scroll is active")

 // TestCopyScrollAnimationFullOutputWindow covers a remote link whose output
 // window is full: the animation holds still, drains the backlog in capped
-// steps once the window reopens, and gives up after about a second of hold.
+// steps once the window reopens, eases freely again once that backlog is
+// drained, and gives up after about a second of hold.
 func TestCopyScrollAnimationFullOutputWindow(t *testing.T) {
 	tests := []struct {
 		name       string
 		heldFrames int
 		reopen     bool
-		wantMoved  int
+		// drainThenFlick drains the held backlog, then starts a new 60-row
-		wantActive bool
+		// flick past the tail deadline; wantMoved counts only that flick.
+		drainThenFlick bool
+		wantMoved      int
+		wantActive     bool
 	}{
 		{name: "full window holds the viewport", heldFrames: 1, wantMoved: 0, wantActive: true},
 		{name: "reopened window drains in capped steps", heldFrames: 1, reopen: true, wantMoved: copyScrollMaxStep, wantActive: true},
+		{name: "drained backlog lifts the cap for the next flick", heldFrames: 1, reopen: true, drainThenFlick: true, wantMoved: 60, wantActive: false},
 		{name: "long hold abandons the scroll", heldFrames: copyScrollMaxHeldFrames + 1, wantMoved: 0, wantActive: false},
 	}
 	for _, tt := range tests {
 				require.True(t, changed)
 				require.False(t, exit)
 			}
+			if tt.drainThenFlick {
+				for rt.copyScroll.remaining != 0 {
+					f.ac.ackOutputState(f.ac.output.currentEpoch(), f.ac.output.next)
+					rt.copyScroll.timer.stop()
+					changed, exit := f.d.advanceCopyScrollLocked(f.sess, f.ac)
+					require.True(t, changed)
+					require.False(t, exit)
+				}
+				start = rt.copyMode.ViewportTop
+				rt.copyScroll.remaining = -60
+				changed, exit := f.d.advanceCopyScrollLocked(f.sess, f.ac)
+				require.True(t, changed)
+				require.False(t, exit)
+			}
 			require.Equal(t, tt.wantMoved, start-rt.copyMode.ViewportTop)
 			require.Equal(t, tt.wantActive, rt.copyScroll.remaining != 0)
 			require.Equal(t, tt.wantActive, rt.copyScroll.timer.timer != nil, "the frame timer stays armed only while the scroll is active")