QNetworkRequest: make the default ctor implicit

As in QVarLengthArray (c34242c679aaea6ee1badf6c1e5f274f925f5f50), this will
probably bite someone someday, so fix it before there's a bug report.

Use ctor delegation to keep code size increase small.

There's also the benefit that default-constructing a QNetworkRequest now
no longer creates an expensive QUrl object just to destroy it unused again.

Add an auto-test.

Change-Id: I5ceb5402ca3946048d695244d1b1c36564a1e80a
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

2 files changed, 14 insertions, 2 deletions

diff --git a/src/network/access/qnetworkrequest.cpp b/src/network/access/qnetworkrequest.cpp
index ba36c75419..c82eb8fe9f 100644
--- a/src/network/access/qnetworkrequest.cpp
+++ b/src/network/access/qnetworkrequest.cpp
@@ -468,13 +468,24 @@ public:
 };
 
 /*!
+    Constructs a QNetworkRequest object with no URL to be requested.
+    Use setUrl() to set one.
+
+    \sa url(), setUrl()
+*/
+QNetworkRequest::QNetworkRequest()
+    : d(new QNetworkRequestPrivate)
+{
+}
+
+/*!
     Constructs a QNetworkRequest object with \a url as the URL to be
     requested.
 
     \sa url(), setUrl()
 */
 QNetworkRequest::QNetworkRequest(const QUrl &url)
-    : d(new QNetworkRequestPrivate)
+    : QNetworkRequest()
 {
     d->url = url;
 }
diff --git a/src/network/access/qnetworkrequest.h b/src/network/access/qnetworkrequest.h
index 846ead1592..8ad4ab41c0 100644
--- a/src/network/access/qnetworkrequest.h
+++ b/src/network/access/qnetworkrequest.h
@@ -128,7 +128,8 @@ public:
     };
 
 
-    explicit QNetworkRequest(const QUrl &url = QUrl());
+    QNetworkRequest();
+    explicit QNetworkRequest(const QUrl &url);
     QNetworkRequest(const QNetworkRequest &other);
     ~QNetworkRequest();
     QNetworkRequest &operator=(QNetworkRequest &&other) noexcept { swap(other); return *this; }