VcsBase: Fix a crash on shutdown

Since GitClient is a static object, it's being deleted after
the git plugin is unloaded. We can't make it a parent of VcsCommand
instances, as the process reaper may be already gone.

Use ExtensionSystem::shutdownGuard() as a parent for VcsCommand
instances instead.

This commit reverts d5e8f70192.

Amends d5e8f70192

Fixes: QTCREATORBUG-31549
Change-Id: I27e6abbfcac2746e8fa4c447010aab43c11444a9
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: André Hartmann <aha_1980@gmx.de>

src/plugins/bazaar/bazaarplugin.cpp

@@ -949,7 +949,7 @@ VcsCommand *BazaarPluginPrivate::createInitialCheckoutCommand(const QString &url
 {
     Environment env = m_client.processEnvironment(baseDirectory);
     env.set("BZR_PROGRESS_BAR", "text");
-    auto command = VcsBaseClient::createVcsCommand(this, baseDirectory, env);
+    auto command = VcsBaseClient::createVcsCommand(baseDirectory, env);
     command->addJob({m_client.vcsBinary(baseDirectory),
         {m_client.vcsCommandString(BazaarClient::CloneCommand), extraArgs, url, localName}}, -1);
     return command;

src/plugins/cvs/cvsplugin.cpp

@@ -413,8 +413,7 @@ VcsCommand *CvsPluginPrivate::createInitialCheckoutCommand(const QString &url,
     QStringList args;
     args << QLatin1String("checkout") << url << extraArgs;
 
-    auto command = VcsBaseClient::createVcsCommand(this, baseDirectory,
+    auto command = VcsBaseClient::createVcsCommand(baseDirectory, Environment::systemEnvironment());
-                                                   Environment::systemEnvironment());
     command->setDisplayName(Tr::tr("CVS Checkout"));
     command->addJob({settings().binaryPath(), settings().addOptions(args)}, -1);
     return command;

src/plugins/fossil/fossilplugin.cpp

@@ -931,7 +931,7 @@ VcsCommand *FossilPluginPrivate::createInitialCheckoutCommand(const QString &sou
     checkoutPath.createDir();
 
     // Setup the wizard page command job
-    auto command = VcsBaseClient::createVcsCommand(this, checkoutPath,
+    auto command = VcsBaseClient::createVcsCommand(checkoutPath,
                                                    fossilClient().processEnvironment(checkoutPath));
 
     if (!isLocalRepository

src/plugins/git/gitplugin.cpp

@@ -1838,7 +1838,7 @@ VcsCommand *GitPluginPrivate::createInitialCheckoutCommand(const QString &url,
                                                            const QString &localName,
                                                            const QStringList &extraArgs)
 {
-    auto command = VcsBaseClient::createVcsCommand(this, baseDirectory,
+    auto command = VcsBaseClient::createVcsCommand(baseDirectory,
                                                    gitClient().processEnvironment(baseDirectory));
     command->addFlags(RunFlags::SuppressStdErr);
     command->addJob({gitClient().vcsBinary(baseDirectory),

src/plugins/mercurial/mercurialplugin.cpp

@@ -733,7 +733,7 @@ VcsCommand *MercurialPluginPrivate::createInitialCheckoutCommand(const QString &
                                                                  const QString &localName,
                                                                  const QStringList &extraArgs)
 {
-    auto command = VcsBaseClient::createVcsCommand(this, baseDirectory,
+    auto command = VcsBaseClient::createVcsCommand(baseDirectory,
                    mercurialClient().processEnvironment(baseDirectory));
     command->addJob({settings().binaryPath(), {"clone", extraArgs, url, localName}}, -1);
     return command;

src/plugins/subversion/subversionplugin.cpp

@@ -1149,7 +1149,7 @@ VcsCommand *SubversionPluginPrivate::createInitialCheckoutCommand(const QString
     args << SubversionClient::AddAuthOptions();
     args << Subversion::Constants::NON_INTERACTIVE_OPTION << extraArgs << url << localName;
 
-    auto command = VcsBaseClient::createVcsCommand(this, baseDirectory,
+    auto command = VcsBaseClient::createVcsCommand(baseDirectory,
                    subversionClient().processEnvironment(baseDirectory));
     command->addJob(args, -1);
     return command;

src/plugins/vcsbase/vcsbaseclient.cpp

@@ -16,6 +16,8 @@
 #include <coreplugin/editormanager/editormanager.h>
 #include <coreplugin/idocument.h>
 
+#include <extensionsystem/shutdownguard.h>
+
 #include <texteditor/textdocument.h>
 
 #include <utils/commandline.h>
@@ -71,8 +73,7 @@ FilePath VcsBaseClientImpl::vcsBinary(const Utils::FilePath &forDirectory) const
 VcsCommand *VcsBaseClientImpl::createCommand(const FilePath &workingDirectory,
                                              VcsBaseEditorWidget *editor) const
 {
-    auto cmd = createVcsCommand(const_cast<VcsBaseClientImpl *>(this),
+    auto cmd = createVcsCommand(workingDirectory, processEnvironment(workingDirectory));
-                                workingDirectory, processEnvironment(workingDirectory));
     if (editor) {
         editor->setCommand(cmd);
         connect(cmd, &VcsCommand::done, editor, [editor, cmd] {
@@ -210,15 +211,9 @@ int VcsBaseClientImpl::vcsTimeoutS() const
 
 VcsCommand *VcsBaseClientImpl::createVcsCommand(const FilePath &defaultWorkingDir,
                                                 const Environment &environment)
-{
-    return new VcsCommand(defaultWorkingDir, environment);
-}
-
-VcsCommand *VcsBaseClientImpl::createVcsCommand(QObject *parent, const FilePath &defaultWorkingDir,
-                                                const Environment &environment)
 {
     auto command = new VcsCommand(defaultWorkingDir, environment);
-    command->setParent(parent);
+    command->setParent(ExtensionSystem::shutdownGuard());
     return command;
 }
 

src/plugins/vcsbase/vcsbaseclient.h

@@ -42,11 +42,8 @@ public:
     virtual Utils::FilePath vcsBinary(const Utils::FilePath &forDirectory) const;
     int vcsTimeoutS() const;
 
-    // TODO: For master: remove this overload.
     static VcsCommand *createVcsCommand(const Utils::FilePath &defaultWorkingDir,
                                         const Utils::Environment &environment);
-    static VcsCommand *createVcsCommand(QObject *parent, const Utils::FilePath &defaultWorkingDir,
-                                        const Utils::Environment &environment);
 
     VcsBaseEditorWidget *createVcsEditor(Utils::Id kind, QString title,
                                          const Utils::FilePath &source, QTextCodec *codec,