Add support for plugin paths set by the installer

This is important on macOS, where we cannot install optional plugins
into the app bundle, because that would break code signing.
Instead the install settings in the signed bundle sets a custom plugin
path outside the bundle, and the installer puts optional plugins there.

Task-number: QTCREATORBUG-26705
Change-Id: I8b36752471d16dfc5828e87e20254f39ab985ca2
Reviewed-by: David Schulz <david.schulz@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

1 files changed, 37 insertions, 8 deletions

diff --git a/src/app/main.cpp b/src/app/main.cpp
index bdd80ed34e..74d1ccec9e 100644
--- a/src/app/main.cpp
+++ b/src/app/main.cpp
@@ -217,16 +217,37 @@ static inline QStringList getPluginPaths()
     return rc;
 }
 
-static void setupInstallSettings(QString &installSettingspath)
+// Returns plugin path that is set in install settings.
+// The installer (or rather the packaging) can write that to load optional plugins from
+// outside the application bundle on macOS, because installing optional plugins into
+// the application bundle would break code signing.
+static QStringList getInstallPluginPaths()
+{
+    // uses SystemScope because this really must be an "installation" setting
+    QSettings installSettings(QSettings::IniFormat,
+                              QSettings::SystemScope,
+                              QLatin1String(Core::Constants::IDE_SETTINGSVARIANT_STR),
+                              QLatin1String(Core::Constants::IDE_CASED_ID));
+    return Utils::transform(installSettings.value("Settings/InstallPluginPaths").toStringList(),
+                            [](const QString &path) -> QString {
+                                if (QDir::isRelativePath(path))
+                                    return applicationDirPath() + '/' + path;
+                                return path;
+                            });
+}
+
+static void setupInstallSettings(QString &installSettingspath, bool redirect = true)
 {
     if (!installSettingspath.isEmpty() && !QFileInfo(installSettingspath).isDir()) {
         displayError(QString("-installsettingspath \"%0\" needs to be the path where a %1/%2.ini exist.").arg(installSettingspath,
             QLatin1String(Core::Constants::IDE_SETTINGSVARIANT_STR), QLatin1String(Core::Constants::IDE_CASED_ID)));
         installSettingspath.clear();
     }
-    static const char kInstallSettingsKey[] = "Settings/InstallSettings";
-    QSettings::setPath(QSettings::IniFormat, QSettings::SystemScope,
-        installSettingspath.isEmpty() ? resourcePath() : installSettingspath);
+    QSettings::setPath(QSettings::IniFormat,
+                       QSettings::SystemScope,
+                       installSettingspath.isEmpty() ? resourcePath() : installSettingspath);
+    if (!redirect) // ignore redirection via Settings/InstallSettings
+        return;
 
     // Check if the default install settings contain a setting for the actual install settings.
     // This can be an absolute path, or a path relative to applicationDirPath().
@@ -236,6 +257,7 @@ static void setupInstallSettings(QString &installSettingspath)
     // yet a second time. So try this a few times.
     // (Only the first time with QSettings::UserScope, to allow setting the install settings path
     // in the user settings.)
+    static const char kInstallSettingsKey[] = "Settings/InstallSettings";
     QSettings::Scope scope = QSettings::UserScope;
     int count = 0;
     bool containsInstallSettingsKey = false;
@@ -542,9 +564,11 @@ int main(int argc, char **argv)
 
     // Must be done before any QSettings class is created
     QSettings::setDefaultFormat(QSettings::IniFormat);
-    setupInstallSettings(options.installSettingsPath);
-    // plugin manager takes control of this settings object
 
+    // HiDPI variables need to be set before creating QApplication.
+    // Since we do not have a QApplication yet, we cannot rely on QApplication::applicationDirPath()
+    // though. So we set up install settings with a educated guess here, and re-setup it later.
+    setupInstallSettings(options.installSettingsPath);
     setHighDpiEnvironmentVariable();
 
     SharedTools::QtSingleApplication::setAttribute(Qt::AA_ShareOpenGLContexts);
@@ -563,7 +587,11 @@ int main(int argc, char **argv)
 
     const QStringList pluginArguments = app.arguments();
 
-    /*Initialize global settings and resetup install settings with QApplication::applicationDirPath */
+    // Re-setup install settings with QApplication::applicationDirPath() available, but
+    // first read install plugin paths from original install settings, without redirection
+    setupInstallSettings(options.installSettingsPath, /*redirect=*/false);
+    const QStringList installPluginPaths = getInstallPluginPaths();
+    // Re-setup install settings for real
     setupInstallSettings(options.installSettingsPath);
     Utils::QtcSettings *settings = createUserSettings();
     Utils::QtcSettings *globalSettings
@@ -645,7 +673,8 @@ int main(int argc, char **argv)
     QNetworkProxyFactory::setUseSystemConfiguration(true);
 
     // Load
-    const QStringList pluginPaths = getPluginPaths() + options.customPluginPaths;
+    const QStringList pluginPaths = getPluginPaths() + installPluginPaths
+                                    + options.customPluginPaths;
     PluginManager::setPluginPaths(pluginPaths);
     QMap<QString, QString> foundAppOptions;
     if (pluginArguments.size() > 1) {