From 21f512eddf243b05f650431b942758b38582b518 Mon Sep 17 00:00:00 2001
From: Muxi Yan <mxyan@google.com>
Date: Mon, 3 Jun 2019 11:22:30 -0700
Subject: [PATCH] Make a copy of received headers

---
 src/objective-c/GRPCClient/GRPCCall.m | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/objective-c/GRPCClient/GRPCCall.m b/src/objective-c/GRPCClient/GRPCCall.m
index 71b03f15f17..5a3440f84ed 100644
--- a/src/objective-c/GRPCClient/GRPCCall.m
+++ b/src/objective-c/GRPCClient/GRPCCall.m
@@ -714,7 +714,12 @@ const char *kCFStreamVarName = "grpc_cfstream";
     __strong GRPCCall *strongSelf = weakSelf;
     if (strongSelf) {
       @synchronized(strongSelf) {
-        strongSelf.responseHeaders = headers;
+        // it is ok to set nil because headers are only received once
+        strongSelf.responseHeaders = nil;
+        // copy the header so that the GRPCOpRecvMetadata object may be dealloc'ed
+        NSDictionary *copiedHeaders = [[NSDictionary alloc] initWithDictionary:headers
+                                                                     copyItems:YES];
+        strongSelf.responseHeaders = copiedHeaders;
         strongSelf->_pendingCoreRead = NO;
         [strongSelf maybeStartNextRead];
       }