From 632a3e37af30ca17934d2d511d7b79e8f11cb4ba Mon Sep 17 00:00:00 2001
From: Krzysztof Piaskowy <krzysztof.piaskowy@swmansion.com>
Date: Wed, 9 Sep 2026 23:17:31 +0200
Subject: [PATCH] fix(ios): rebuild a pattern player once it has been stopped
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Apple's contract for `startAtTime:` only promises a rewind for a player
that is already playing: "If you call this method on a player that's
already playing, it restarts itself at the beginning of the pattern."
Nothing covers a stopped player, and the basic CHHapticPatternPlayer has
no way to rewind one — seek(toOffset:) exists only on the advanced
player. A stopped player stays parked at its stop offset, so starting it
again produces no output.

Stopping a player therefore unregisters it, and the next play rebuilds
it from its pattern through the path already used after an engine reset.
---
 .../Sources/Pulsar/HapticEngineWrapper.swift   |  9 +++++++--
 .../PulsarTests/CoreHapticsMockTests.swift     | 18 ++++++++++++++++++
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/iOS/Pulsar/Sources/Pulsar/HapticEngineWrapper.swift b/iOS/Pulsar/Sources/Pulsar/HapticEngineWrapper.swift
index 5e4bbbe0..6aeb4c6f 100644
--- a/iOS/Pulsar/Sources/Pulsar/HapticEngineWrapper.swift
+++ b/iOS/Pulsar/Sources/Pulsar/HapticEngineWrapper.swift
@@ -122,6 +122,7 @@ public extension HapticEngineWrapper {
   func stopPlayer(id: Int) {
     guard let player = playerRegistry[id] else { return }
     stopPlayer(player, errorPrefix: "Error stopping player")
+    unregisterPlayer(id)
   }
 
   func removePlayer(id: Int) {
@@ -129,8 +130,7 @@ public extension HapticEngineWrapper {
       try? player.stop(atTime: 0)
     }
 
-    playerRegistry.removeValue(forKey: id)
-    playerCreationOrder.removeAll { $0 == id }
+    unregisterPlayer(id)
   }
 }
 
@@ -350,6 +350,11 @@ private extension HapticEngineWrapper {
     playerCreationOrder.append(id)
   }
 
+  func unregisterPlayer(_ id: Int) {
+    playerRegistry.removeValue(forKey: id)
+    playerCreationOrder.removeAll { $0 == id }
+  }
+
   func evictOldestPlayerIfNeeded() {
     guard playerRegistry.count >= playerLimit else { return }
 
diff --git a/iOS/Pulsar/Tests/PulsarTests/CoreHapticsMockTests.swift b/iOS/Pulsar/Tests/PulsarTests/CoreHapticsMockTests.swift
index 2dab27db..f9b184cc 100644
--- a/iOS/Pulsar/Tests/PulsarTests/CoreHapticsMockTests.swift
+++ b/iOS/Pulsar/Tests/PulsarTests/CoreHapticsMockTests.swift
@@ -67,6 +67,24 @@ struct CoreHapticsMockTests {
         #expect(HapticMockRecorder.shared.playerStops >= 1)
     }
 
+    @Test func playingAfterAStopBuildsAFreshPlayer() {
+        CoreHapticsMock.install()
+        defer { CoreHapticsMock.uninstall() }
+
+        let engine = activeEngine()
+        let pattern = makePattern()
+        let created = engine.createPlayer(pattern: pattern)
+        #expect(created != nil)
+        guard let id = created else { return }
+
+        engine.playPlayer(id: id, pattern: pattern)
+        engine.stopPlayer(id: id)
+        engine.playPlayer(id: id, pattern: pattern)
+
+        #expect(HapticMockRecorder.shared.playersCreated == 2)
+        #expect(HapticMockRecorder.shared.playerStarts == 2)
+    }
+
     @Test func stopHapticsStopsEveryRegisteredPlayer() {
         CoreHapticsMock.install()
         defer { CoreHapticsMock.uninstall() }