From a4f36b10d25c7fa859ccdf55796ca64a066f647e Mon Sep 17 00:00:00 2001
From: onevcat <onevcat@gmail.com>
Date: Fri, 15 Nov 2024 23:44:05 +0900
Subject: [PATCH] Fix a potential duplicated completion invoking when task
 cancel

There seems to be a short period that the callback can be accessed from another thread before the next lock
---
 Sources/Networking/SessionDataTask.swift | 5 ++++-
 Sources/Networking/SessionDelegate.swift | 3 ++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/Sources/Networking/SessionDataTask.swift b/Sources/Networking/SessionDataTask.swift
index cd6c4e21d..ae5448e22 100644
--- a/Sources/Networking/SessionDataTask.swift
+++ b/Sources/Networking/SessionDataTask.swift
@@ -101,10 +101,13 @@ public class SessionDataTask: @unchecked Sendable {
         return nil
     }
     
-    func removeAllCallbacks() -> Void {
+    @discardableResult
+    func removeAllCallbacks() -> [TaskCallback] {
         lock.lock()
         defer { lock.unlock() }
+        let callbacks = callbacksStore.values
         callbacksStore.removeAll()
+        return Array(callbacks)
     }
 
     func resume() {
diff --git a/Sources/Networking/SessionDelegate.swift b/Sources/Networking/SessionDelegate.swift
index 9c901d811..63470896b 100644
--- a/Sources/Networking/SessionDelegate.swift
+++ b/Sources/Networking/SessionDelegate.swift
@@ -263,7 +263,8 @@ extension SessionDelegate: URLSessionDataDelegate {
         guard let sessionTask = self.task(for: task) else {
             return
         }
-        sessionTask.onTaskDone.call((result, sessionTask.callbacks))
+        let callbacks = sessionTask.removeAllCallbacks()
+        sessionTask.onTaskDone.call((result, callbacks))
         remove(sessionTask)
     }
 }