input: join calibration workers before destroying their owner

The detached worker could use complete_event after its owner was destroyed. Retain and join it after signaling stop. Bind the test server to loopback on Windows and verify capture release across 32 cancellations.

Assisted-by: Codex (implementation, review and automated validation)
(cherry picked from commit 0eb7b4855f499838d056a0d5d678109318517e9d)

3 files changed, 22 insertions, 3 deletions

diff --git a/src/input_common/drivers/udp_client.cpp b/src/input_common/drivers/udp_client.cpp
index 620e0cf630..a7840db32f 100644
--- a/src/input_common/drivers/udp_client.cpp
+++ b/src/input_common/drivers/udp_client.cpp
@@ -603,7 +603,7 @@ CalibrationConfigurationJob::CalibrationConfigurationJob(
     const std::string& host, u16 port, std::function<void(Status)> status_callback,
     std::function<void(u16, u16, u16, u16)> data_callback) {
 
-    std::thread([=, this] {
+    worker = std::jthread([=, this] {
         u16 min_x{UINT16_MAX};
         u16 min_y{UINT16_MAX};
         u16 max_x{};
@@ -647,7 +647,7 @@ CalibrationConfigurationJob::CalibrationConfigurationJob(
         complete_event.Wait();
         socket.Stop();
         worker_thread.join();
-    }).detach();
+    });
 }
 
 CalibrationConfigurationJob::~CalibrationConfigurationJob() {
diff --git a/src/input_common/drivers/udp_client.h b/src/input_common/drivers/udp_client.h
index cea9f579ac..eac3df07aa 100644
--- a/src/input_common/drivers/udp_client.h
+++ b/src/input_common/drivers/udp_client.h
@@ -183,6 +183,7 @@ public:
 
 private:
     Common::Event complete_event;
+    std::jthread worker;
 };
 
 void TestCommunication(const std::string& host, u16 port,
diff --git a/src/tests/input_common/calibration_configuration_job.cpp b/src/tests/input_common/calibration_configuration_job.cpp
index 6ded0dfc86..c45ef157a5 100644
--- a/src/tests/input_common/calibration_configuration_job.cpp
+++ b/src/tests/input_common/calibration_configuration_job.cpp
@@ -5,6 +5,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <array>
+#include <memory>
 #include <string>
 #include <thread>
 #include <utility>
@@ -19,7 +20,7 @@
 class FakeCemuhookServer {
 public:
     FakeCemuhookServer()
-        : socket(io_context, boost::asio::ip::udp::endpoint(boost::asio::ip::udp::v4(), 0)) {}
+        : socket(io_context, boost::asio::ip::udp::endpoint(boost::asio::ip::address_v4::loopback(), 0)) {}
 
     ~FakeCemuhookServer() {
         boost::system::error_code error_code;
@@ -132,3 +133,20 @@ TEST_CASE("CalibrationConfigurationJob completed", "[input_common]") {
     REQUIRE(max_x == 200);
     REQUIRE(max_y == 200);
 }
+
+TEST_CASE("CalibrationConfigurationJob cancellation joins its worker", "[input_common]") {
+    FakeCemuhookServer server;
+    for (unsigned i = 0; i < 32; ++i) {
+        auto lifetime = std::make_shared<int>(0);
+        std::weak_ptr<int> observer = lifetime;
+        {
+            InputCommon::CemuhookUDP::CalibrationConfigurationJob job(
+                server.GetHost(), server.GetPort(),
+                [lifetime](InputCommon::CemuhookUDP::CalibrationConfigurationJob::Status) {},
+                [](u16, u16, u16, u16) {});
+            lifetime.reset();
+            job.Stop();
+        }
+        REQUIRE(observer.expired());
+    }
+}