plugin: Handle invalid values being set for active and enabled languages

When a language is not found in the known paths, reset the value, and
remove it if also set in enabled languages.

src/plugin/inputmethod.cpp

@@ -340,6 +340,10 @@ void InputMethod::onEnabledLanguageSettingsChanged()
 {
     Q_D(InputMethod);
     d->enabledLanguages = d->m_settings.enabledLanguages();
+    // Reset the value if it gets unset
+    if (d->enabledLanguages.length() == 0) {
+        d->m_settings.resetEnabledLanguages();
+    }
     // Switch to first language in enabled languages if the currently active
     // language is no longer enabled
     if (!d->enabledLanguages.contains(d->activeLanguage)) {
@@ -604,20 +608,33 @@ void InputMethod::selectNextLanguage()
 //! \brief InputMethod::setActiveLanguage
 //! Sets the currently active/used language
 //! \param newLanguage id of the new language. For example "en" or "es"
-//! FIXME check if the language is supported - if not use "en" as fallback
 void InputMethod::setActiveLanguage(const QString &newLanguage)
 {
     Q_D(InputMethod);
 
     qDebug() << "in inputMethod.cpp setActiveLanguage() activeLanguage is:" << newLanguage;
 
+    QString newPluginPath;
     foreach(QString pluginPath, d->languagesPaths) {
         QDir testDir(pluginPath + QDir::separator() + newLanguage);
         if (testDir.exists()) {
-            d->currentPluginPath = testDir.absolutePath();
+            newPluginPath = testDir.absolutePath();
             break;
         }
     }
+    // The language plpugin was not found, so reset the active language
+    if (newPluginPath.isEmpty()) {
+        d->m_settings.resetActiveLanguage();
+        // If the plugin was not found, and was in enabledLanguages list,
+        // also remove it from there
+        auto enabled = enabledLanguages();
+        if (enabled.contains(newLanguage)) {
+            enabled.removeAll(newLanguage);
+            d->m_settings.setEnabledLanguages(enabled);
+        }
+        return;
+    }
+    d->currentPluginPath = newPluginPath;
 
     if (d->activeLanguage == newLanguage)
         return;

src/plugin/keyboardsettings.cpp

@@ -72,10 +72,7 @@ KeyboardSettings::KeyboardSettings(QObject *parent) :
     auto enabled = enabledLanguages();
     if (enabled.contains(emoji)) {
         enabled.removeAll(emoji);
-        if (enabled.isEmpty()) {
-            enabled << QLatin1String("en");
-        }
-        m_settings->set(ENABLED_LANGUAGES_KEY, enabled);
+        setEnabledLanguages(enabled);
     }
     if (activeLanguage() == emoji) {
         setActiveLanguage(enabled[0]);
@@ -97,6 +94,11 @@ void KeyboardSettings::setActiveLanguage(const QString& id)
     m_settings->set(ACTIVE_LANGUAGE_KEY, QVariant(id));
 }
 
+void KeyboardSettings::resetActiveLanguage()
+{
+    m_settings->reset(ACTIVE_LANGUAGE_KEY);
+}
+
 /*!
  * \brief KeyboardSettings::enabledLanguages returns a list of languages that are
  * active
@@ -107,6 +109,20 @@ QStringList KeyboardSettings::enabledLanguages() const
     return m_settings->get(ENABLED_LANGUAGES_KEY).toStringList();
 }
 
+void KeyboardSettings::setEnabledLanguages(const QStringList& ids)
+{
+    if (ids.isEmpty()) {
+        resetEnabledLanguages();
+        return;
+    }
+    m_settings->set(ENABLED_LANGUAGES_KEY, ids);
+}
+
+void KeyboardSettings::resetEnabledLanguages()
+{
+    m_settings->reset(ENABLED_LANGUAGES_KEY);
+}
+
 /*!
  * \brief KeyboardSettings::autoCapitalization returns true id the first letter
  * of each sentence should be capitalized

src/plugin/keyboardsettings.h

@@ -45,7 +45,10 @@ class KeyboardSettings : public QObject
 
     QString activeLanguage() const;
     void setActiveLanguage(const QString& id);
+    void resetActiveLanguage();
     QStringList enabledLanguages() const;
+    void setEnabledLanguages(const QStringList& ids);
+    void resetEnabledLanguages();
     bool autoCapitalization() const;
     bool autoCompletion() const;
     bool predictiveText() const;