diff --git a/pythonlanguagesupport.cpp b/pythonlanguagesupport.cpp
index 5954ceee..32d54b43 100644
--- a/pythonlanguagesupport.cpp
+++ b/pythonlanguagesupport.cpp
@@ -1,194 +1,199 @@
 /*****************************************************************************
  * Copyright (c) 2007 Andreas Pakulat <apaku@gmx.de>                         *
  * Copyright (c) 2007 Piyush verma <piyush.verma@gmail.com>                  *
  * Copyright (c) 2012 Sven Brauch <svenbrauch@gmail.com>                     *
  *                                                                           *
  * This program is free software; you can redistribute it and/or             *
  * modify it under the terms of the GNU General Public License as            *
  * published by the Free Software Foundation; either version 2 of            *
  * the License, or (at your option) any later version.                       *
  *                                                                           *
  * This program is distributed in the hope that it will be useful,           *
  * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the             *
  * GNU General Public License for more details.                              *
  *                                                                           *
  * You should have received a copy of the GNU General Public License         *
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.     *
  *****************************************************************************
  */
 
 #include "pythonlanguagesupport.h"
 
 #include <QMutexLocker>
+#include <QReadWriteLock>
 
 #include <KPluginFactory>
 #include <KPluginLoader>
 
 #include <interfaces/icore.h>
 #include <interfaces/ilanguagecontroller.h>
 #include <interfaces/iplugincontroller.h>
 #include <interfaces/idocument.h>
 #include <interfaces/isourceformatter.h>
 #include <interfaces/idocumentcontroller.h>
 #include <interfaces/context.h>
 #include <interfaces/contextmenuextension.h>
 #include <interfaces/iprojectcontroller.h>
 #include <interfaces/iproject.h>
 #include <interfaces/isession.h>
 #include <language/assistant/renameassistant.h>
 #include <language/assistant/staticassistantsmanager.h>
 #include <language/interfaces/editorcontext.h>
 #include <language/duchain/duchain.h>
 #include <language/duchain/duchainlock.h>
 #include <language/codecompletion/codecompletion.h>
 #include <language/codecompletion/codecompletionmodel.h>
 
 #include "pythonparsejob.h"
 #include "pythonhighlighting.h"
 #include "duchain/pythoneditorintegrator.h"
 #include "codecompletion/model.h"
 #include "codegen/refactoring.h"
 #include "codegen/correctionfilegenerator.h"
 #include "kdevpythonversion.h"
 #include "pep8kcm/kcm_pep8.h"
 #include "docfilekcm/kcm_docfiles.h"
 
 #include <QDebug>
 #include "pythondebug.h"
 
 using namespace KDevelop;
 
 K_PLUGIN_FACTORY_WITH_JSON( KDevPythonSupportFactory, "kdevpythonsupport.json", registerPlugin<Python::LanguageSupport>(); )
 
 namespace Python
 {
 LanguageSupport* LanguageSupport::m_self = 0;
 
 KDevelop::ContextMenuExtension LanguageSupport::contextMenuExtension(KDevelop::Context* context)
 {
     ContextMenuExtension cm;
     EditorContext *ec = dynamic_cast<KDevelop::EditorContext *>(context);
 
     if (ec && ICore::self()->languageController()->languagesForUrl(ec->url()).contains(this)) {
         // It's a Python file, let's add our context menu.
         m_refactoring->fillContextMenu(cm, context);
         TypeCorrection::self().doContextMenu(cm, context);
     }
     return cm;
 }
 
 LanguageSupport::LanguageSupport( QObject* parent, const QVariantList& /*args*/ )
     : KDevelop::IPlugin("pythonlanguagesupport", parent )
     , KDevelop::ILanguageSupport()
     , m_highlighting( new Highlighting( this ) )
     , m_refactoring( new Refactoring( this ) )
 {
     KDEV_USE_EXTENSION_INTERFACE( KDevelop::ILanguageSupport )
     KDEV_USE_EXTENSION_INTERFACE( KDevelop::ILanguageCheckProvider )
 
     m_self = this;
 
     PythonCodeCompletionModel* codeCompletion = new PythonCodeCompletionModel(this);
     new KDevelop::CodeCompletion(this, codeCompletion, "Python");
 
     auto assistantsManager = core()->languageController()->staticAssistantsManager();
     assistantsManager->registerAssistant(StaticAssistant::Ptr(new RenameAssistant(this)));
 
     QObject::connect(ICore::self()->documentController(), &IDocumentController::documentOpened,
                      this, &LanguageSupport::documentOpened);
 }
 
 void LanguageSupport::documentOpened(IDocument* doc)
 {
     if ( ! ICore::self()->languageController()->languagesForUrl(doc->url()).contains(this) ) {
         // not a python file
         return;
     }
 
     DUChainReadLocker lock;
     TopDUContextPointer topContext = TopDUContextPointer(DUChain::self()->chainForDocument(doc->url()));
     lock.unlock();
     ParseJob::eventuallyDoPEP8Checking(IndexedString(doc->url()), topContext.data());
 }
 
 LanguageSupport::~LanguageSupport()
 {
+    parseLock()->lockForWrite();
+    // By locking the parse-mutexes, we make sure that parse jobs get a chance to finish in a good state
+    parseLock()->unlock();
+
     delete m_highlighting;
     m_highlighting = 0;
 }
 
 KDevelop::ParseJob *LanguageSupport::createParseJob( const IndexedString& url )
 {
     return new ParseJob(url, this);
 }
 
 QString LanguageSupport::name() const
 {
     return "Python";
 }
 
 LanguageSupport* LanguageSupport::self()
 {
     return m_self;
 }
 
 SourceFormatterItemList LanguageSupport::sourceFormatterItems() const
 {
     SourceFormatterStyle autopep8("autopep8");
     autopep8.setCaption("autopep8");
     autopep8.setDescription(i18n("Format source with the autopep8 formatter."));
     autopep8.setOverrideSample("class klass:\n def method(arg1,arg2):\n  a=3+5\n"
                                "def function(arg,*vararg,**kwargs): return arg+kwarg[0]\nfunction(3, 5, 7)");
     using P = SourceFormatterStyle::MimeHighlightPair;
     autopep8.setMimeTypes(SourceFormatterStyle::MimeList{ P{"text/x-python", "Python"} });
     QString autopep8path = QStandardPaths::findExecutable("autopep8");
     if (autopep8path.isEmpty()) {
         // TODO: proper error handling/user notification
         qWarning() << "Could not find the autopep8 executable";
         autopep8path = "/usr/bin/autopep8";
     }
     autopep8.setContent(autopep8path + " -i $TMPFILE");
 
     return SourceFormatterItemList{SourceFormatterStyleItem{"customscript", autopep8}};
 }
 
 KDevelop::ICodeHighlighting* LanguageSupport::codeHighlighting() const
 {
     return m_highlighting;
 }
 
 BasicRefactoring* LanguageSupport::refactoring() const
 {
     return m_refactoring;
 }
 
 ILanguageSupport::WhitespaceSensitivity LanguageSupport::whitespaceSensititivy() const
 {
     return ILanguageSupport::IndentOnly;
 }
 
 QList<ILanguageCheck*> LanguageSupport::providedChecks()
 {
     return {};
 }
 
 int LanguageSupport::configPages() const
 {
     return 2;
 }
 
 KDevelop::ConfigPage* LanguageSupport::configPage(int number, QWidget* parent)
 {
     if (number == 0) {
         return new PEP8KCModule(this, parent);
     } else if (number == 1) {
         return new DocfilesKCModule(this, parent);
     }
     return nullptr;
 }
 
 
 }
 
 #include "pythonlanguagesupport.moc"