VcsCommand: Block auto reload while a command is running

Git rebase is executed in the background, and it can change a file multiple
times in a short period. If we reparse a file while this happens on
Windows, Git fails to replace it, the rebase action fails and the
repository becomes unstable (remains with a modified file).

See discussion at https://github.com/git-for-windows/git/pull/1666

Task-number: QTCREATORBUG-15449
Change-Id: Iba40a770a1df2dfff0dd1c874c491dfbe1cceb58
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/libs/utils/shellcommand.cpp

@@ -276,6 +276,7 @@ void ShellCommand::run(QFutureInterface<void> &future)
     QString stdOut;
     QString stdErr;
 
+    emit started();
     if (d->m_progressParser)
         d->m_progressParser->setFuture(&future);
     else

src/libs/utils/shellcommand.h

@@ -154,6 +154,7 @@ public:
 signals:
     void stdOutText(const QString &);
     void stdErrText(const QString &);
+    void started();
     void finished(bool ok, int exitCode, const QVariant &cookie);
     void success(const QVariant &cookie);
 

src/plugins/coreplugin/documentmanager.cpp

@@ -157,6 +157,7 @@ public:
 
     QFileSystemWatcher *m_fileWatcher = nullptr; // Delayed creation.
     QFileSystemWatcher *m_linkWatcher = nullptr; // Delayed creation (only UNIX/if a link is seen).
+    bool m_postponeAutoReload = false;
     bool m_blockActivated = false;
     bool m_checkOnFocusChange = false;
     QString m_lastVisitedDirectory = QDir::currentPath();
@@ -597,6 +598,13 @@ void DocumentManager::unexpectFileChange(const QString &fileName)
         updateExpectedState(filePathKey(fileName, ResolveLinks));
 }
 
+void DocumentManager::setAutoReloadPostponed(bool postponed)
+{
+    d->m_postponeAutoReload = postponed;
+    if (!postponed)
+        QTimer::singleShot(500, m_instance, &DocumentManager::checkForReload);
+}
+
 static bool saveModifiedFilesHelper(const QList<IDocument *> &documents,
                                     const QString &message, bool *cancelled, bool silently,
                                     const QString &alwaysSaveMessage, bool *alwaysSave,
@@ -990,7 +998,7 @@ void DocumentManager::changedFile(const QString &fileName)
 
 void DocumentManager::checkForReload()
 {
-    if (d->m_changedFiles.isEmpty())
+    if (d->m_postponeAutoReload || d->m_changedFiles.isEmpty())
         return;
     if (QApplication::applicationState() != Qt::ApplicationActive)
         return;

src/plugins/coreplugin/documentmanager.h

@@ -69,6 +69,8 @@ public:
     static void expectFileChange(const QString &fileName);
     static void unexpectFileChange(const QString &fileName);
 
+    static void setAutoReloadPostponed(bool enabled);
+
     // recent files
     static void addToRecentFiles(const QString &fileName, Id editorId = Id());
     Q_SLOT void clearRecentFiles();

src/plugins/vcsbase/vcscommand.cpp

@@ -27,6 +27,7 @@
 #include "vcsbaseplugin.h"
 #include "vcsoutputwindow.h"
 
+#include <coreplugin/documentmanager.h>
 #include <coreplugin/vcsmanager.h>
 #include <utils/synchronousprocess.h>
 
@@ -56,6 +57,14 @@ VcsCommand::VcsCommand(const QString &workingDirectory,
 
         return proxy;
     });
+    connect(this, &VcsCommand::started, this, [this] {
+        if (flags() & ExpectRepoChanges)
+            Core::DocumentManager::setAutoReloadPostponed(true);
+    });
+    connect(this, &VcsCommand::finished, this, [this] {
+        if (flags() & ExpectRepoChanges)
+            Core::DocumentManager::setAutoReloadPostponed(false);
+    });
 }
 
 const QProcessEnvironment VcsCommand::processEnvironment() const