fix(daemon): preserve render deadline across ack

commit: 91e8bae4162b7b30401e942f2825a388e338af23
author: brice · 3mo ago · 2026-07-11 18:55 UTC
parent: dfcd8eb
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email

1 file · +25 -8

M internal/usecase/daemon/render_coordinator.go +25 -8


@@ -113,7 +113,10 @@ type renderCoordinator struct {
113	113		// viewers may consume a coalesced target snapshot while that target is
114	114		// still ACK-blocked.
115	115		pendingPreview bool
116		-	coalesced int
	116	+	// ackDeferred records that an expired deadline or watchdog was blocked by
	117	+	// output-window capacity. ACK notifications may flush only this state.
	118	+	ackDeferred bool
	119	+	coalesced int
117	120		// outputPressure carries recent bulk-burst pressure between completed
118	121		// batches. It selects a bounded 8–16ms deadline without letting a busy
119	122		// batch perpetually reset its own timer.

@@ -205,6 +208,9 @@ func (c *renderCoordinator) invalidate(inv renderInvalidation) {
205	208		}
206	209		c.metrics.invalidations.Add(1)
207	210		wasPending, wasUrgent, wasPreviewPending := c.pending, c.pendingUrgent, c.pendingPreview
	211	+	if !wasPending {
	212	+	c.ackDeferred = false
	213	+	}
208	214		c.pending = true
209	215		c.pendingReset = c.pendingReset \|\| inv.reset
210	216		c.pendingUrgent = c.pendingUrgent \|\| inv.class == invalidateUrgent

@@ -238,7 +244,7 @@ func (c *renderCoordinator) invalidate(inv renderInvalidation) {
238	244		if timerC == nil {
239	245		c.mu.Unlock()
240	246		timer.Stop()
241		-	c.fire(gen, false)
	247	+	c.fire(gen, false, true)
242	248		return
243	249		}
244	250		cancel := make(chan struct{})

@@ -249,7 +255,7 @@ func (c *renderCoordinator) invalidate(inv renderInvalidation) {
249	255		defer close(done)
250	256		select {
251	257		case <-timerC:
252		-	c.fire(gen, false)
	258	+	c.fire(gen, false, true)
253	259		case <-cancel:
254	260		}
255	261		}()

@@ -259,12 +265,17 @@ func (c *renderCoordinator) invalidate(inv renderInvalidation) {
259	265		}
260	266
261	267		// notifyAck reports that the client acknowledged an output state, releasing
262		-	// at most one deferred wake.
	268	+	// at most one deadline/watchdog-deferred wake. It never bypasses an unexpired
	269	+	// normal or urgent deadline.
263	270		func (c *renderCoordinator) notifyAck() {
264	271		c.mu.Lock()
	272	+	if !c.ackDeferred \|\| !c.pending {
	273	+	c.mu.Unlock()
	274	+	return
	275	+	}
265	276		gen := c.generation
266	277		c.mu.Unlock()
267		-	c.fire(gen, false)
	278	+	c.fire(gen, false, false)
268	279		}
269	280
270	281		// noteSyncBegin records a synchronized-output batch for its stable pane and

@@ -401,6 +412,7 @@ func (c renderCoordinator) noteDetach(ac attachedClient) {
401	412		if c.attachment == ac {
402	413		c.attachment = nil
403	414		c.pending = false
	415	+	c.ackDeferred = false
404	416		c.pendingPreview = false
405	417		c.generation++
406	418		c.armed = false

@@ -417,6 +429,7 @@ func (c renderCoordinator) noteReplace(old, replacement attachedClient) {
417	429		if c.attachment == old {
418	430		c.attachment = replacement
419	431		c.pending = false
	432	+	c.ackDeferred = false
420	433		c.pendingPreview = false
421	434		c.generation++
422	435		c.armed = false

@@ -437,6 +450,7 @@ func (c *renderCoordinator) noteSessionTeardown() {
437	450		c.previewWake = nil
438	451		c.previewWakes = nil
439	452		c.pending = false
	453	+	c.ackDeferred = false
440	454		c.pendingPreview = false
441	455		c.generation++
442	456		c.armed = false

@@ -487,7 +501,7 @@ func (c *renderCoordinator) fireCurrent(watchdog bool) {
487	501		c.mu.Lock()
488	502		gen := c.generation
489	503		c.mu.Unlock()
490		-	c.fire(gen, watchdog)
	504	+	c.fire(gen, watchdog, watchdog)
491	505		}
492	506
493	507		// invalidateRender is the sole producer fan-in. In tests and transitional

@@ -521,7 +535,7 @@ func (d Daemon) invalidateRenderNow(sess session, ac *attachedClient, reset bo
521	535		}
522	536		}
523	537
524		-	func (c *renderCoordinator) fire(gen uint64, watchdog bool) {
	538	+	func (c *renderCoordinator) fire(gen uint64, watchdog, deadline bool) {
525	539		c.mu.Lock()
526	540		if c.torndown \|\| !c.pending \|\| (!watchdog && gen != c.generation) {
527	541		c.mu.Unlock()

@@ -534,6 +548,9 @@ func (c *renderCoordinator) fire(gen uint64, watchdog bool) {
534	548		w := renderWake{reset: c.pendingReset, urgent: c.pendingUrgent, coalesced: c.coalesced, watchdog: watchdog}
535	549		preview, previews := c.takePendingPreviewsLocked()
536	550		if c.opts.ackReady != nil && !c.opts.ackReady() {
	551	+	if deadline {
	552	+	c.ackDeferred = true
	553	+	}
537	554		c.mu.Unlock()
538	555		c.notifyPreviews(w, preview, previews)
539	556		return

@@ -551,7 +568,7 @@ func (c *renderCoordinator) fire(gen uint64, watchdog bool) {
551	568		}
552	569		}
553	570		c.cancelNormalTimerLocked()
554		-	c.pending, c.pendingReset, c.pendingUrgent, c.coalesced, c.armed = false, false, false, 0, false
	571	+	c.pending, c.pendingReset, c.pendingUrgent, c.ackDeferred, c.coalesced, c.armed = false, false, false, false, 0, false
555	572		wake := c.opts.wake
556	573		c.mu.Unlock()
557	574		if wake != nil {

 	// viewers may consume a coalesced target snapshot while that target is
 	// still ACK-blocked.
 	pendingPreview bool
-	coalesced      int
+	// ackDeferred records that an expired deadline or watchdog was blocked by
+	// output-window capacity. ACK notifications may flush only this state.
+	ackDeferred bool
+	coalesced   int
 	// outputPressure carries recent bulk-burst pressure between completed
 	// batches. It selects a bounded 8–16ms deadline without letting a busy
 	// batch perpetually reset its own timer.
 	}
 	c.metrics.invalidations.Add(1)
 	wasPending, wasUrgent, wasPreviewPending := c.pending, c.pendingUrgent, c.pendingPreview
+	if !wasPending {
+		c.ackDeferred = false
+	}
 	c.pending = true
 	c.pendingReset = c.pendingReset || inv.reset
 	c.pendingUrgent = c.pendingUrgent || inv.class == invalidateUrgent
 	if timerC == nil {
 		c.mu.Unlock()
 		timer.Stop()
-		c.fire(gen, false)
+		c.fire(gen, false, true)
 		return
 	}
 	cancel := make(chan struct{})
 		defer close(done)
 		select {
 		case <-timerC:
-			c.fire(gen, false)
+			c.fire(gen, false, true)
 		case <-cancel:
 		}
 	}()
 }
 // notifyAck reports that the client acknowledged an output state, releasing
-// at most one deferred wake.
+// at most one deadline/watchdog-deferred wake. It never bypasses an unexpired
+// normal or urgent deadline.
 func (c *renderCoordinator) notifyAck() {
 	c.mu.Lock()
+	if !c.ackDeferred || !c.pending {
+		c.mu.Unlock()
+		return
+	}
 	gen := c.generation
 	c.mu.Unlock()
-	c.fire(gen, false)
+	c.fire(gen, false, false)
 }
 // noteSyncBegin records a synchronized-output batch for its stable pane and
 	if c.attachment == ac {
 		c.attachment = nil
 		c.pending = false
+		c.ackDeferred = false
 		c.pendingPreview = false
 		c.generation++
 		c.armed = false
 	if c.attachment == old {
 		c.attachment = replacement
 		c.pending = false
+		c.ackDeferred = false
 		c.pendingPreview = false
 		c.generation++
 		c.armed = false
 	c.previewWake = nil
 	c.previewWakes = nil
 	c.pending = false
+	c.ackDeferred = false
 	c.pendingPreview = false
 	c.generation++
 	c.armed = false
 	c.mu.Lock()
 	gen := c.generation
 	c.mu.Unlock()
-	c.fire(gen, watchdog)
+	c.fire(gen, watchdog, watchdog)
 }
 // invalidateRender is the sole producer fan-in. In tests and transitional
 	}
 }
-func (c *renderCoordinator) fire(gen uint64, watchdog bool) {
+func (c *renderCoordinator) fire(gen uint64, watchdog, deadline bool) {
 	c.mu.Lock()
 	if c.torndown || !c.pending || (!watchdog && gen != c.generation) {
 		c.mu.Unlock()
 	w := renderWake{reset: c.pendingReset, urgent: c.pendingUrgent, coalesced: c.coalesced, watchdog: watchdog}
 	preview, previews := c.takePendingPreviewsLocked()
 	if c.opts.ackReady != nil && !c.opts.ackReady() {
+		if deadline {
+			c.ackDeferred = true
+		}
 		c.mu.Unlock()
 		c.notifyPreviews(w, preview, previews)
 		return
 		}
 	}
 	c.cancelNormalTimerLocked()
-	c.pending, c.pendingReset, c.pendingUrgent, c.coalesced, c.armed = false, false, false, 0, false
+	c.pending, c.pendingReset, c.pendingUrgent, c.ackDeferred, c.coalesced, c.armed = false, false, false, false, 0, false
 	wake := c.opts.wake
 	c.mu.Unlock()
 	if wake != nil {