consoleprocess: use empty string as default terminal

Using empty string as default terminal avoids storing a path to
QtCreator resources (which becomes invalid if creator is deleted)
on mac.

Change-Id: I9d5fe9bce38387d82de451652df6be9ec5eb5960
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/libs/utils/consoleprocess.cpp

@@ -141,11 +141,11 @@ QString ConsoleProcess::msgCannotExecute(const QString & p, const QString &why)
     return tr("Cannot execute '%1': %2").arg(p, why);
 }
 
-QString ConsoleProcess::terminalEmulator(const QSettings *settings)
+QString ConsoleProcess::terminalEmulator(const QSettings *settings, bool nonEmpty)
 {
     if (settings) {
         const QString value = settings->value(QLatin1String("General/TerminalEmulator")).toString();
-        if (!value.isEmpty())
+        if (!nonEmpty || !value.isEmpty())
             return value;
     }
     return defaultTerminalEmulator();

src/libs/utils/consoleprocess.h

@@ -96,7 +96,7 @@ public:
 
     static QString defaultTerminalEmulator();
     static QStringList availableTerminalEmulators();
-    static QString terminalEmulator(const QSettings *settings);
+    static QString terminalEmulator(const QSettings *settings, bool nonEmpty = true);
     static void setTerminalEmulator(QSettings *settings, const QString &term);
 
 signals:

src/plugins/coreplugin/generalsettings.cpp

@@ -116,9 +116,11 @@ QWidget *GeneralSettings::createPage(QWidget *parent)
     m_page->reloadBehavior->setCurrentIndex(EditorManager::instance()->reloadSetting());
 #ifdef Q_OS_UNIX
     const QStringList availableTerminals = ConsoleProcess::availableTerminalEmulators();
-    const QString currentTerminal = ConsoleProcess::terminalEmulator(settings);
+    const QString currentTerminal = ConsoleProcess::terminalEmulator(settings, false);
+    const QString currentTerminalExplicit = ConsoleProcess::terminalEmulator(settings, true);
     m_page->terminalComboBox->addItems(availableTerminals);
     m_page->terminalComboBox->lineEdit()->setText(currentTerminal);
+    m_page->terminalComboBox->lineEdit()->setPlaceholderText(currentTerminalExplicit);
 #else
     m_page->terminalLabel->hide();
     m_page->terminalComboBox->hide();
@@ -214,7 +216,7 @@ void GeneralSettings::resetWarnings()
 void GeneralSettings::resetTerminal()
 {
 #if defined(Q_OS_UNIX)
-    m_page->terminalComboBox->lineEdit()->setText(ConsoleProcess::defaultTerminalEmulator());
+    m_page->terminalComboBox->lineEdit()->setText(QString());
 #endif
 }