QDebugStateSaver: Fix trailing space issues

~QDebug() removes any trailing space if autoInsertSpaces() is true.
However, if one uses QDebugStateSaver the global autoInsertSpaces might
be false, but a space was added by a custom operator<<.

Explicitly check for this in QDebugStateSaverPrivate::restoreState. Remove
any trailing space if the local state asks for adding trailing spaces, but
the original one doesn't. Add a trailing space if the local state doesn't
ask for one, but the global state does.

Change-Id: I243b5c76d5ed2c1ec4820da35ab6e254da1551d9
Reviewed-by: David Faure <david.faure@kdab.com>

2 files changed, 31 insertions, 1 deletions

diff --git a/src/corelib/io/qdebug.cpp b/src/corelib/io/qdebug.cpp
index 56c46d69c9..b0411f9dd9 100644
--- a/src/corelib/io/qdebug.cpp
+++ b/src/corelib/io/qdebug.cpp
@@ -438,10 +438,18 @@ public:
     }
     void restoreState()
     {
+        const bool currentSpaces = m_dbg.autoInsertSpaces();
+        if (currentSpaces && !m_spaces)
+            if (m_dbg.stream->buffer.endsWith(QLatin1Char(' ')))
+                m_dbg.stream->buffer.chop(1);
+
         m_dbg.setAutoInsertSpaces(m_spaces);
         m_dbg.stream->ts.d_ptr->params = m_streamParams;
         if (m_dbg.stream->context.version > 1)
             m_dbg.stream->flags = m_flags;
+
+        if (!currentSpaces && m_spaces)
+            m_dbg.stream->ts << ' ';
     }
 
     QDebug &m_dbg;
@@ -475,7 +483,6 @@ QDebugStateSaver::QDebugStateSaver(QDebug &dbg)
 QDebugStateSaver::~QDebugStateSaver()
 {
     d->restoreState();
-    d->m_dbg.maybeSpace();
 }
 
 QT_END_NAMESPACE
diff --git a/tests/auto/corelib/io/qdebug/tst_qdebug.cpp b/tests/auto/corelib/io/qdebug/tst_qdebug.cpp
index 2143a8874c..767fde7f6c 100644
--- a/tests/auto/corelib/io/qdebug/tst_qdebug.cpp
+++ b/tests/auto/corelib/io/qdebug/tst_qdebug.cpp
@@ -254,6 +254,17 @@ void tst_QDebug::stateSaver() const
     MessageHandlerSetter mhs(myMessageHandler);
     {
         QDebug d = qDebug();
+        d << 42;
+        {
+            QDebugStateSaver saver(d);
+            d << 43;
+        }
+        d << 44;
+    }
+    QCOMPARE(s_msg, QString::fromLatin1("42 43 44"));
+
+    {
+        QDebug d = qDebug();
         {
             QDebugStateSaver saver(d);
             d.nospace() << hex << right << qSetFieldWidth(3) << qSetPadChar('0') << 42;
@@ -271,6 +282,18 @@ void tst_QDebug::stateSaver() const
         d << QStringLiteral("World");
     }
     QCOMPARE(s_msg, QString::fromLatin1("Hello \"World\""));
+
+    {
+        QDebug d = qDebug();
+        d.noquote().nospace() << QStringLiteral("Hello") << hex << 42;
+        {
+            QDebugStateSaver saver(d);
+            d.resetFormat();
+            d << QStringLiteral("World") << 42;
+        }
+        d << QStringLiteral("!") << 42;
+    }
+    QCOMPARE(s_msg, QString::fromLatin1("Hello2a\"World\" 42!2a"));
 }
 
 void tst_QDebug::veryLongWarningMessage() const