From 4a6754390cd249d456dcae1a38169bbf844b405a Mon Sep 17 00:00:00 2001
From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Tue, 20 May 2025 10:08:49 +0200
Subject: [PATCH] dnsdist: Fix Coverity's false positives

---
 pdns/dnsdistdist/dnsdist-lua-bindings-dnsquestion.cc | 7 ++++---
 pdns/dnsdistdist/dnsdist-metrics.cc                  | 2 ++
 pdns/dnsdistdist/dnsdist.hh                          | 1 +
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/pdns/dnsdistdist/dnsdist-lua-bindings-dnsquestion.cc b/pdns/dnsdistdist/dnsdist-lua-bindings-dnsquestion.cc
index 4136d9c2d3..049b88a5c1 100644
--- a/pdns/dnsdistdist/dnsdist-lua-bindings-dnsquestion.cc
+++ b/pdns/dnsdistdist/dnsdist-lua-bindings-dnsquestion.cc
@@ -168,7 +168,8 @@ void setupLuaBindingsDNSQuestion([[maybe_unused]] LuaContext& luaCtx)
     return {};
   });
 
-  luaCtx.registerFunction<std::string (DNSQuestion::*)() const>("getProtocol", [](const DNSQuestion& dnsQuestion) {
+  luaCtx.registerFunction<std::string (DNSQuestion::*)() const>("getProtocol", [](const DNSQuestion& dnsQuestion) -> std::string {
+    // coverity[auto_causes_copy]
     return dnsQuestion.getProtocol().toPrettyString();
   });
 
@@ -208,7 +209,7 @@ void setupLuaBindingsDNSQuestion([[maybe_unused]] LuaContext& luaCtx)
     }
     return tagIt->second;
   });
-  luaCtx.registerFunction<QTag (DNSQuestion::*)(void) const>("getTagArray", [](const DNSQuestion& dnsQuestion) {
+  luaCtx.registerFunction<QTag (DNSQuestion::*)(void) const>("getTagArray", [](const DNSQuestion& dnsQuestion) -> QTag {
     if (!dnsQuestion.ids.qTag) {
       QTag empty;
       return empty;
@@ -581,7 +582,7 @@ void setupLuaBindingsDNSQuestion([[maybe_unused]] LuaContext& luaCtx)
     return std::string();
   });
 
-  luaCtx.registerFunction<LuaAssociativeTable<std::string> (DNSQuestion::*)(void) const>("getHTTPHeaders", [](const DNSQuestion& dnsQuestion) {
+  luaCtx.registerFunction<LuaAssociativeTable<std::string> (DNSQuestion::*)(void) const>("getHTTPHeaders", [](const DNSQuestion& dnsQuestion) -> LuaAssociativeTable<std::string> {
 #if defined(HAVE_DNS_OVER_HTTPS)
     if (dnsQuestion.ids.du) {
       // coverity[auto_causes_copy]
diff --git a/pdns/dnsdistdist/dnsdist-metrics.cc b/pdns/dnsdistdist/dnsdist-metrics.cc
index 4ec0fed496..cbb237ed0b 100644
--- a/pdns/dnsdistdist/dnsdist-metrics.cc
+++ b/pdns/dnsdistdist/dnsdist-metrics.cc
@@ -269,6 +269,8 @@ static std::variant<MetricValueType, Error> updateMetric(const std::string_view&
 
   /* OK, so we the metric exists (otherwise we would have returned an Error) but the label doesn't yet */
   {
+    // too bad Coverity claims to understand C++ yet does not understand RAII
+    // coverity[double_lock]
     auto writeLockedMap = metricMap.write_lock();
     auto labelsMapIt = writeLockedMap->find(name);
     if (labelsMapIt == writeLockedMap->end()) {
diff --git a/pdns/dnsdistdist/dnsdist.hh b/pdns/dnsdistdist/dnsdist.hh
index b2826ccf9d..6624e86a45 100644
--- a/pdns/dnsdistdist/dnsdist.hh
+++ b/pdns/dnsdistdist/dnsdist.hh
@@ -967,6 +967,7 @@ struct ServerPool
   void removeServer(shared_ptr<DownstreamState>& server);
   bool isTCPOnly() const
   {
+    // coverity[missing_lock]
     return d_tcpOnly;
   }
 
-- 
2.47.3