fix(httpweb): resolve pending request future on disconnect

HTTPSClientEx canceled its timeout timer on disconnect without completing
the request promise. FileClient::downloadFile() could then block forever
in future::get(), and FileClient's destructor froze the GUI while joining
the download thread on cancel.

Fail the pending promise on disconnect and guard promise completion so a
late response cannot satisfy it twice.

Log: resolve pending request future on disconnect
PMS: TASK-396845
Influence: cancelling a download no longer blocks the GUI while joining the download thread.

Author: re2zero

src/infrastructure/netutil/include/http/https_client.h

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2025 UnionTech Software Technology Co., Ltd.
+// SPDX-FileCopyrightText: 2023 - 2026 UnionTech Software Technology Co., Ltd.
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
 
@@ -11,6 +11,7 @@
 #include "asio/ssl_client.h"
 #include "asio/timer.h"
 
+#include <atomic>
 #include <future>
 
 namespace NetUtil {
@@ -272,6 +273,10 @@ class HTTPSClientEx : public HTTPSClient
     std::shared_ptr<Asio::TCPResolver> _resolver;
     std::shared_ptr<Asio::Timer> _timeout;
     std::promise<HTTPResponse> _promise;
+    // Guards the promise against being completed twice: the timeout handler
+    // and a disconnect can race, and a duplicate set_value/set_exception
+    // throws std::future_error on the IO thread.
+    std::atomic<bool> _promise_pending { false };
 
     void SetPromiseValue(const HTTPResponse& response);
     void SetPromiseError(const std::string& error);

src/infrastructure/netutil/src/http/https_client.cpp

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2025 UnionTech Software Technology Co., Ltd.
+// SPDX-FileCopyrightText: 2023 - 2026 UnionTech Software Technology Co., Ltd.
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
 
@@ -70,6 +70,7 @@ std::future<HTTPResponse> HTTPSClientEx::SendRequest(const HTTPRequest& request,
         _timeout = std::make_shared<Asio::Timer>(service());
 
     _promise = std::promise<HTTPResponse>();
+    _promise_pending.store(true);
     _request = request;
 
     // Check if the HTTP request is valid
@@ -135,7 +136,14 @@ void HTTPSClientEx::onDisconnected()
     if (_timeout)
         _timeout->Cancel();
 
+    // Give a partially received response a chance to complete first.
     HTTPSClient::onDisconnected();
+
+    // The connection dropped while the request was still pending and the
+    // timeout timer above is now canceled: nothing else would ever resolve
+    // the future. Fail it so synchronous callers (FileClient::downloadFile)
+    // do not block forever.
+    SetPromiseError("Disconnected!");
 }
 
 void HTTPSClientEx::onReceivedResponse(const HTTPResponse& response)
@@ -158,12 +166,20 @@ void HTTPSClientEx::onReceivedResponseError(const HTTPResponse& response, const
 
 void HTTPSClientEx::SetPromiseValue(const HTTPResponse& response)
 {
+    // A late response after a timeout/disconnect must not complete the
+    // promise twice, which throws std::future_error on the IO thread.
+    if (!_promise_pending.exchange(false))
+        return;
+
     _promise.set_value(response);
     _request.Clear();
 }
 
 void HTTPSClientEx::SetPromiseError(const std::string& error)
 {
+    if (!_promise_pending.exchange(false))
+        return;
+
     _promise.set_exception(std::make_exception_ptr(std::runtime_error(error)));
     _request.Clear();
 }

tests/manager/httpclient_test.cpp

@@ -0,0 +1,56 @@
+// SPDX-FileCopyrightText: 2026 UnionTech Software Technology Co., Ltd.
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include <gtest/gtest.h>
+
+#include "asioservice.h"
+#include "http/https_client.h"
+#include "manager/secureconfig.h"
+
+#include <QHostAddress>
+#include <QTcpServer>
+#include <QTcpSocket>
+#include <QTest>
+
+#include <chrono>
+
+// A connection dropped before the response arrives must complete the pending
+// request future. Otherwise FileClient::downloadFile() stays blocked in
+// future::get() and FileClient::~FileClient(), which joins the download
+// thread on the GUI thread, freezes the application on cancel.
+TEST(HTTPClientExTest, DisconnectResolvesPendingRequest)
+{
+    QTcpServer server;
+    ASSERT_TRUE(server.listen(QHostAddress::LocalHost, 0));
+    QObject::connect(&server, &QTcpServer::newConnection, &server, [&server] {
+        // Accept the TCP connection but never complete the TLS handshake.
+        while (QTcpSocket *socket = server.nextPendingConnection())
+            socket->abort();
+    });
+
+    auto service = std::make_shared<AsioService>();
+    service->Start();
+
+    auto client = std::make_shared<NetUtil::HTTP::HTTPSClientEx>(
+            service, SecureConfig::clientContext(),
+            "127.0.0.1", server.serverPort());
+    auto future = client->SendGetRequest("download/payload.txt&token=test",
+                                         BaseKit::Timespan::seconds(30));
+
+    // Keep the event loop alive so QTcpServer accepts and drops the socket;
+    // the request timeout is 30 seconds, so a ready future here can only come
+    // from the disconnect handler.
+    for (int i = 0; i < 50
+         && future.wait_for(std::chrono::milliseconds(0)) != std::future_status::ready;
+         ++i) {
+        QTest::qWait(100);
+    }
+
+    ASSERT_EQ(future.wait_for(std::chrono::milliseconds(0)), std::future_status::ready);
+    EXPECT_THROW(future.get(), std::runtime_error);
+
+    client->DisconnectAsync();
+    client.reset();
+    service->Stop();
+}