From 0e712b3812d56a65c03c44016a3181fe979cf69f Mon Sep 17 00:00:00 2001
From: Matthew Zipkin <pinheadmz@pm.me>
Date: Tue, 10 Mar 2026 14:59:35 -0400
Subject: [PATCH] Make DynSock accepted sockets queue optional, with precise
 lifetime

When DynSock is used to represent a connected socket (e.g. a client)
the data I/O pipes are needed but not the m_accepted_sockets Queue,
because connected sockets do not create more connected sockets.

When DynSock is used to represent a listening socket, the Queue
is necessary to create connected sockets upon mocked connection, but
the Queue does not need to be a std::shared_ptr as long as it
is guaranteed to live as long as the DynSock.

Co-Authored by: Hodlinator <172445034+hodlinator@users.noreply.github.com>
---
 src/test/util/net.cpp | 10 ++++++++--
 src/test/util/net.h   | 13 +++++++++++--
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/src/test/util/net.cpp b/src/test/util/net.cpp
index 73e5a58d5d9..15903ac9fd0 100644
--- a/src/test/util/net.cpp
+++ b/src/test/util/net.cpp
@@ -346,11 +346,16 @@ void DynSock::Pipe::WaitForDataOrEof(UniqueLock<Mutex>& lock)
     });
 }
 
-DynSock::DynSock(std::shared_ptr<Pipes> pipes, std::shared_ptr<Queue> accept_sockets)
+DynSock::DynSock(std::shared_ptr<Pipes> pipes, Queue* accept_sockets)
     : m_pipes{pipes}, m_accept_sockets{accept_sockets}
 {
 }
 
+DynSock::DynSock(std::shared_ptr<Pipes> pipes)
+    : m_pipes{pipes}, m_accept_sockets{}
+{
+}
+
 DynSock::~DynSock()
 {
     m_pipes->send.Eof();
@@ -369,6 +374,7 @@ ssize_t DynSock::Send(const void* buf, size_t len, int) const
 
 std::unique_ptr<Sock> DynSock::Accept(sockaddr* addr, socklen_t* addr_len) const
 {
+    assert(m_accept_sockets && "Accept() called on non-listening DynSock");
     ZeroSock::Accept(addr, addr_len);
     return m_accept_sockets->Pop().value_or(nullptr);
 }
@@ -403,7 +409,7 @@ bool DynSock::WaitMany(std::chrono::milliseconds timeout, EventsPerSock& events_
             if ((events.requested & Sock::RECV) != 0) {
                 auto dyn_sock = reinterpret_cast<const DynSock*>(sock.get());
                 uint8_t b;
-                if (dyn_sock->m_pipes->recv.GetBytes(&b, 1, MSG_PEEK) == 1 || !dyn_sock->m_accept_sockets->Empty()) {
+                if (dyn_sock->m_pipes->recv.GetBytes(&b, 1, MSG_PEEK) == 1 || (dyn_sock->m_accept_sockets && !dyn_sock->m_accept_sockets->Empty())) {
                     events.occurred |= Sock::RECV;
                     at_least_one_event_occurred = true;
                 }
diff --git a/src/test/util/net.h b/src/test/util/net.h
index 247eba8ea0f..8954e631d3d 100644
--- a/src/test/util/net.h
+++ b/src/test/util/net.h
@@ -5,6 +5,7 @@
 #ifndef BITCOIN_TEST_UTIL_NET_H
 #define BITCOIN_TEST_UTIL_NET_H
 
+#include <attributes.h>
 #include <compat/compat.h>
 #include <netmessagemaker.h>
 #include <net.h>
@@ -336,7 +337,15 @@ public:
      * @param[in] pipes Send/recv pipes used by the Send() and Recv() methods.
      * @param[in] accept_sockets Sockets to return by the Accept() method.
      */
-    explicit DynSock(std::shared_ptr<Pipes> pipes, std::shared_ptr<Queue> accept_sockets);
+    explicit DynSock(std::shared_ptr<Pipes> pipes, Queue* accept_sockets LIFETIMEBOUND);
+
+    /**
+     * Create a new mocked sock that represents a connected socket. It has pipes
+     * for data transport but there is no queue because connected sockets do
+     * not introduce new connected sockets.
+     * @param[in] pipes Send/recv pipes used by the Send() and Recv() methods.
+     */
+    explicit DynSock(std::shared_ptr<Pipes> pipes);
 
     ~DynSock();
 
@@ -356,7 +365,7 @@ private:
     DynSock& operator=(Sock&&) override;
 
     std::shared_ptr<Pipes> m_pipes;
-    std::shared_ptr<Queue> m_accept_sockets;
+    Queue* const m_accept_sockets;
 };
 
 template <typename... Args>