From 07b7ea777e15884d6405028a727fdd675d7e6d19 Mon Sep 17 00:00:00 2001
From: Yijie Ma <yijiem@google.com>
Date: Tue, 19 Dec 2023 14:09:09 -0800
Subject: [PATCH] [EventEngine] Return error instead of assertion when hostname
 is empty in cf_engine (#35353)

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Closes #35353

COPYBARA_INTEGRATE_REVIEW=https://github.com/grpc/grpc/pull/35353 from yijiem:fix-ios-dns-test f84d29a9dbbad6dd2d7b52dc3718ea961dca9d7a
PiperOrigin-RevId: 592339589
---
 .../lib/event_engine/cf_engine/dns_service_resolver.cc   | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/core/lib/event_engine/cf_engine/dns_service_resolver.cc b/src/core/lib/event_engine/cf_engine/dns_service_resolver.cc
index a202e815abe..fc02cbd566a 100644
--- a/src/core/lib/event_engine/cf_engine/dns_service_resolver.cc
+++ b/src/core/lib/event_engine/cf_engine/dns_service_resolver.cc
@@ -50,7 +50,14 @@ void DNSServiceResolverImpl::LookupHostname(
     });
     return;
   }
-  GPR_ASSERT(!host.empty());
+  if (host.empty()) {
+    engine_->Run([on_resolve = std::move(on_resolve),
+                  status = absl::InvalidArgumentError(absl::StrCat(
+                      "host must not be empty in name: ", name))]() mutable {
+      on_resolve(status);
+    });
+    return;
+  }
   if (port_string.empty()) {
     if (default_port.empty()) {
       engine_->Run([on_resolve = std::move(on_resolve),