Http: Improve error string when there is no reason phrase

The reason phrase is optional, and in http2+ it is not included at all.
So when we generate the error string as 'server replied: %2' it ends
up being unnatural and ugly, and certainly not fit for display.

To improve that, whenever there is no reason phrase, we instead
generate the string like 'server replied with status code %2'
and output the status code instead, which is included.

Fixes: QTBUG-140126
Pick-to: 6.10 6.9 6.8
Change-Id: Ife3ed920f6e1a15d83e5cd5dc9b0568fb195b642
Reviewed-by: Timur Pocheptsov <[email protected]>
Reviewed-by: Mate Barany <[email protected]>

2 files changed, 73 insertions, 11 deletions

diff --git a/src/network/access/qhttpthreaddelegate.cpp b/src/network/access/qhttpthreaddelegate.cpp
index 45a5c167265..fbbc55dc4a4 100644
--- a/src/network/access/qhttpthreaddelegate.cpp
+++ b/src/network/access/qhttpthreaddelegate.cpp
@@ -488,6 +488,21 @@ void QHttpThreadDelegate::readyReadSlot()
     }
 }
 
+static QString makeServerErrorString(int code, const QUrl &url, const QString &reasonPhrase)
+{
+    QString msg;
+    if (!reasonPhrase.isEmpty()) {
+        msg = QLatin1StringView(QT_TRANSLATE_NOOP("QNetworkReply",
+                                                  "Error transferring %1 - server replied: %2"))
+                      .arg(url.toString(), reasonPhrase);
+    } else {
+        msg = QLatin1StringView(QT_TRANSLATE_NOOP("QNetworkReply",
+                                                  "Error transferring %1 - server replied with status code %2"))
+                      .arg(url.toString(), QString::number(code));
+    }
+    return msg;
+}
+
 void QHttpThreadDelegate::finishedSlot()
 {
     if (!httpReply)
@@ -509,12 +524,11 @@ void QHttpThreadDelegate::finishedSlot()
 #endif
 
     if (httpReply->statusCode() >= 400) {
-            // it's an error reply
-            QString msg = QLatin1StringView(QT_TRANSLATE_NOOP("QNetworkReply",
-                                                              "Error transferring %1 - server replied: %2"));
-            msg = msg.arg(httpRequest.url().toString(), httpReply->reasonPhrase());
-            emit error(statusCodeFromHttp(httpReply->statusCode(), httpRequest.url()), msg);
-        }
+        // it's an error reply
+        QString msg = makeServerErrorString(httpReply->statusCode(), httpRequest.url(),
+                                            httpReply->reasonPhrase());
+        emit error(statusCodeFromHttp(httpReply->statusCode(), httpRequest.url()), msg);
+    }
 
     if (httpRequest.isFollowRedirects() && httpReply->isRedirecting())
         emit redirected(httpReply->redirectUrl(), httpReply->statusCode(), httpReply->request().redirectCount() - 1);
@@ -535,11 +549,10 @@ void QHttpThreadDelegate::synchronousFinishedSlot()
     qDebug() << "QHttpThreadDelegate::synchronousFinishedSlot() thread=" << QThread::currentThreadId() << "result=" << httpReply->statusCode();
 #endif
     if (httpReply->statusCode() >= 400) {
-            // it's an error reply
-            QString msg = QLatin1StringView(QT_TRANSLATE_NOOP("QNetworkReply",
-                                                              "Error transferring %1 - server replied: %2"));
-            incomingErrorDetail = msg.arg(httpRequest.url().toString(), httpReply->reasonPhrase());
-            incomingErrorCode = statusCodeFromHttp(httpReply->statusCode(), httpRequest.url());
+        // it's an error reply
+        incomingErrorDetail = makeServerErrorString(httpReply->statusCode(), httpRequest.url(),
+                                                    httpReply->reasonPhrase());
+        incomingErrorCode = statusCodeFromHttp(httpReply->statusCode(), httpRequest.url());
     }
 
     isCompressed = httpReply->isCompressed();
diff --git a/tests/auto/network/access/qnetworkreply/tst_qnetworkreply.cpp b/tests/auto/network/access/qnetworkreply/tst_qnetworkreply.cpp
index d33e31cdb1d..a4e8a569c02 100644
--- a/tests/auto/network/access/qnetworkreply/tst_qnetworkreply.cpp
+++ b/tests/auto/network/access/qnetworkreply/tst_qnetworkreply.cpp
@@ -532,6 +532,8 @@ private Q_SLOTS:
 
     void ioHttpSingleRedirect();
     void ioHttpChangeMaxRedirects();
+    void ioHttpErrorString_data();
+    void ioHttpErrorString();
     void ioHttpRedirectErrors_data();
     void ioHttpRedirectErrors();
     void ioHttpRedirectPolicy_data();
@@ -9180,6 +9182,53 @@ void tst_QNetworkReply::ioHttpChangeMaxRedirects()
     QVERIFY(validateRedirectedResponseHeaders(reply2));
 }
 
+void tst_QNetworkReply::ioHttpErrorString_data()
+{
+    QTest::addColumn<int>("statusCode");
+    QTest::addColumn<QString>("reasonPhrase");
+
+    QTest::newRow("404 - page not found") << 404 << "page not found";
+    QTest::newRow("404 - <no reason provided>") << 404 << QString();
+    QTest::newRow("500 - internal error") << 500 << "internal error";
+    QTest::newRow("500 - <no reason provided>") << 500 << QString();
+}
+
+void tst_QNetworkReply::ioHttpErrorString()
+{
+    QFETCH(const int, statusCode);
+    QFETCH(const QString, reasonPhrase);
+
+    QString serverReply = uR"(HTTP/1.1 %1%2
+    content-type: text/plain
+
+    Hello world)"_s;
+    if (reasonPhrase.isEmpty())
+        serverReply = serverReply.arg(QString::number(statusCode), "");
+    else
+        serverReply = serverReply.arg(QString::number(statusCode), u" " % reasonPhrase);
+    MiniHttpServer server(serverReply.toUtf8());
+
+    QUrl serverAddress;
+    serverAddress.setScheme(u"http"_s);
+    serverAddress.setHost(u"127.0.0.1"_s);
+    serverAddress.setPort(server.serverPort());
+
+    QNetworkRequest request(serverAddress);
+    QNetworkReplyPtr reply(manager.get(request));
+
+    QTRY_VERIFY(reply->isFinished());
+    QCOMPARE_NE(reply->error(), QNetworkReply::NoError);
+    if (!reasonPhrase.isEmpty()) {
+        QCOMPARE(reply->errorString(),
+                 "Error transferring %1 - server replied: %2"_L1.arg(serverAddress.toString(),
+                                                                     reasonPhrase));
+    } else {
+        QCOMPARE(reply->errorString(),
+                 "Error transferring %1 - server replied with status code %2"_L1.arg(
+                         serverAddress.toString(), QString::number(statusCode)));
+    }
+}
+
 void tst_QNetworkReply::ioHttpRedirectErrors_data()
 {
     QTest::addColumn<QString>("url");