From 667cae878eca239e24c2b38b31bf44325d33bc41 Mon Sep 17 00:00:00 2001
From: Boris Zbarsky <bzbarsky@apple.com>
Date: Sat, 15 Jun 2024 00:21:42 -0400
Subject: [PATCH] Improve error messages in Darwin DNS-SD implementation.
 (#33930)

We shouldn't claim a canceled browse that found things is a failure.
---
 src/platform/Darwin/DnssdContexts.cpp | 14 +++++++++++++-
 src/platform/Darwin/DnssdImpl.h       |  1 +
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/platform/Darwin/DnssdContexts.cpp b/src/platform/Darwin/DnssdContexts.cpp
index fc68a5d779616b..4e88df40ee596d 100644
--- a/src/platform/Darwin/DnssdContexts.cpp
+++ b/src/platform/Darwin/DnssdContexts.cpp
@@ -350,7 +350,17 @@ BrowseContext::BrowseContext(void * cbContext, DnssdBrowseCallback cb, DnssdServ
 
 void BrowseContext::DispatchFailure(const char * errorStr, CHIP_ERROR err)
 {
-    ChipLogError(Discovery, "Mdns: Browse failure (%s)", errorStr);
+    if (err == CHIP_ERROR_CANCELLED && dispatchedSuccessOnce)
+    {
+        // We've been canceled after finding some devices.  Treat this as a
+        // success, because maybe (common case, in fact) those were the devices
+        // our consumer was looking for.
+        ChipLogProgress(Discovery, "Mdns: Browse canceled");
+    }
+    else
+    {
+        ChipLogError(Discovery, "Mdns: Browse failure (%s)", errorStr);
+    }
     callback(context, nullptr, 0, true, err);
     MdnsContexts::GetInstance().Remove(this);
 }
@@ -376,6 +386,8 @@ void BrowseContext::DispatchPartialSuccess()
     sDispatchedServices        = nullptr;
     sContextDispatchingSuccess = nullptr;
     services.clear();
+
+    dispatchedSuccessOnce = true;
 }
 
 void BrowseContext::OnBrowse(DNSServiceFlags flags, const char * name, const char * type, const char * domain, uint32_t interfaceId)
diff --git a/src/platform/Darwin/DnssdImpl.h b/src/platform/Darwin/DnssdImpl.h
index 3bf78fac6cb2bd..23044070f52362 100644
--- a/src/platform/Darwin/DnssdImpl.h
+++ b/src/platform/Darwin/DnssdImpl.h
@@ -169,6 +169,7 @@ struct BrowseContext : public BrowseHandler
 {
     DnssdBrowseCallback callback;
     std::vector<std::pair<DnssdService, std::string>> services;
+    bool dispatchedSuccessOnce = false;
 
     BrowseContext(void * cbContext, DnssdBrowseCallback cb, DnssdServiceProtocol cbContextProtocol);