From eb9ce0e23df467ecd4c1d6f80d1205ffea3bd8e0 Mon Sep 17 00:00:00 2001
From: Chris Streeter <streeter@users.noreply.github.com>
Date: Sat, 4 Jan 2020 15:24:33 -0800
Subject: [PATCH] Use dispatch_barrier_sync (#4474)

This should hopefully avoid any problems where we attempt to write an
HTTP header to a deallocated header dictionary.

See https://github.com/AFNetworking/AFNetworking/pull/3891
See https://github.com/AFNetworking/AFNetworking/issues/3636
Modified from https://github.com/tmm1/AFNetworking/commit/32760e7a3a1cca2817ec498708182ec99584651a

Fixes #1391
---
 AFNetworking/AFURLRequestSerialization.m | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/AFNetworking/AFURLRequestSerialization.m b/AFNetworking/AFURLRequestSerialization.m
index 75672f2bda..f60b6f9d8a 100644
--- a/AFNetworking/AFURLRequestSerialization.m
+++ b/AFNetworking/AFURLRequestSerialization.m
@@ -313,7 +313,7 @@ - (NSDictionary *)HTTPRequestHeaders {
 - (void)setValue:(NSString *)value
 forHTTPHeaderField:(NSString *)field
 {
-    dispatch_barrier_async(self.requestHeaderModificationQueue, ^{
+    dispatch_barrier_sync(self.requestHeaderModificationQueue, ^{
         [self.mutableHTTPRequestHeaders setValue:value forKey:field];
     });
 }
@@ -335,7 +335,7 @@ - (void)setAuthorizationHeaderFieldWithUsername:(NSString *)username
 }
 
 - (void)clearAuthorizationHeader {
-    dispatch_barrier_async(self.requestHeaderModificationQueue, ^{
+    dispatch_barrier_sync(self.requestHeaderModificationQueue, ^{
         [self.mutableHTTPRequestHeaders removeObjectForKey:@"Authorization"];
     });
 }