From 2b6a8c91f1d9ac4f28d85413e22d97e946a5dc4c Mon Sep 17 00:00:00 2001
From: tiennm99 <tiennm99@outlook.com>
Date: Thu, 30 Apr 2026 19:47:22 +0700
Subject: [PATCH] fix(master): break effect_update_depth_exceeded loop in
 countdown
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Two $effects were reading state they also wrote, turning each into its
own dependency:

- AutoCountdown reset effect: `now = tickStart` read tickStart after
  writing it. Use a local snapshot so neither rune is read post-write.
- MasterPanel auto-call effect: `tickCount++` read tickCount. Drop the
  bump here — AutoCountdown's reset effect already re-baselines on the
  rising edge of `running` and on `duration` change, so re-arms remain
  covered. handleDrawNext keeps its per-draw bump (not in effect scope).
---
 web/src/lib/AutoCountdown.svelte |  7 +++++--
 web/src/lib/MasterPanel.svelte   | 10 ++++------
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/web/src/lib/AutoCountdown.svelte b/web/src/lib/AutoCountdown.svelte
index b13a4d1..9d090ae 100644
--- a/web/src/lib/AutoCountdown.svelte
+++ b/web/src/lib/AutoCountdown.svelte
@@ -24,12 +24,15 @@
 
   // Re-baseline whenever the parent bumps tickKey, running flips on, or
   // duration changes mid-run (e.g. host moves the speed slider).
+  // Use a local snapshot so we don't read `tickStart` after writing it —
+  // that would make this effect depend on its own write and infinite-loop.
   $effect(() => {
     tickKey; // subscribe
     duration; // subscribe — keeps the contract explicit, not parent-coupled
     if (running) {
-      tickStart = performance.now();
-      now = tickStart;
+      const t = performance.now();
+      tickStart = t;
+      now = t;
     }
   });
 
diff --git a/web/src/lib/MasterPanel.svelte b/web/src/lib/MasterPanel.svelte
index 6cd463f..eb4cf3a 100644
--- a/web/src/lib/MasterPanel.svelte
+++ b/web/src/lib/MasterPanel.svelte
@@ -123,12 +123,10 @@
       autoRunning = false;
       return;
     }
-    // Re-baseline countdown on every (re-)arm: rising edge of autoRunning,
-    // speed change, autoCallEnabled toggle. handleDrawNext bumps it again
-    // per tick so the ring re-fills before the next interval elapses.
-    // Safe self-write: this effect doesn't read tickCount, so the bump
-    // can't re-trigger it.
-    tickCount++;
+    // No tickCount bump here on purpose: `tickCount++` would read tickCount
+    // and turn this effect into its own dependency (effect_update_depth_exceeded).
+    // AutoCountdown's reset effect already re-baselines on `running` rising
+    // edge and on `duration` change, so re-arms are covered without our help.
     const ms = settings.autoCallSpeed * 1000;
     const id = setInterval(() => {
       if (!state || state.remaining.length === 0) {