Link with Qt: Prepare for sdktool to move to a different location

When linking we should now consider the new sdktool location within the
Qt installation first. The new location of QtCreator.ini will be <Qt>/
Tools/sdktool/QtProject/QtCreator.ini on macOS, and <Qt>/Tools/sdktool/
share/qtcreator/QtProject/QtCreator.ini on Windows/Linux.

When resolving an existing install settings path to the old location
within the Qt Creator installation (Qt Creator.app/Contents/Resources or
Tools/QtCreator/share/qtcreator), the QtCreator.ini at that location
will itself redirect to the new sdktool location. So, try to follow that
as well, to keep existing setups working.

Task-number: QTBUG-28101
Change-Id: Idbb09ad6961f6fd4a4112830959a615d8186a132
Reviewed-by: David Schulz <david.schulz@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

2 files changed, 27 insertions, 14 deletions

diff --git a/src/app/main.cpp b/src/app/main.cpp
index ee7ddbd203..d56cc67602 100644
--- a/src/app/main.cpp
+++ b/src/app/main.cpp
@@ -244,22 +244,35 @@ static void setupInstallSettings(QString &installSettingspath)
             QLatin1String(Core::Constants::IDE_SETTINGSVARIANT_STR), QLatin1String(Core::Constants::IDE_CASED_ID)));
         installSettingspath.clear();
     }
-    // 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().
-    // The result is interpreted like -settingspath, but for SystemScope
     static const char kInstallSettingsKey[] = "Settings/InstallSettings";
     QSettings::setPath(QSettings::IniFormat, QSettings::SystemScope,
         installSettingspath.isEmpty() ? resourcePath() : installSettingspath);
 
-    QSettings installSettings(QSettings::IniFormat, QSettings::UserScope,
-                              QLatin1String(Core::Constants::IDE_SETTINGSVARIANT_STR),
-                              QLatin1String(Core::Constants::IDE_CASED_ID));
-    if (installSettings.contains(kInstallSettingsKey)) {
-        QString installSettingsPath = installSettings.value(kInstallSettingsKey).toString();
-        if (QDir::isRelativePath(installSettingsPath))
-            installSettingsPath = applicationDirPath() + '/' + installSettingsPath;
-        QSettings::setPath(QSettings::IniFormat, QSettings::SystemScope, installSettingsPath);
-    }
+    // 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().
+    // The result is interpreted like -settingspath, but for SystemScope.
+    //
+    // Through the sdktool split that is upcoming, the new install settings might redirect
+    // 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.)
+    QSettings::Scope scope = QSettings::UserScope;
+    int count = 0;
+    bool containsInstallSettingsKey = false;
+    do {
+        QSettings installSettings(QSettings::IniFormat, scope,
+                                  QLatin1String(Core::Constants::IDE_SETTINGSVARIANT_STR),
+                                  QLatin1String(Core::Constants::IDE_CASED_ID));
+        containsInstallSettingsKey = installSettings.contains(kInstallSettingsKey);
+        if (containsInstallSettingsKey) {
+            QString newInstallSettingsPath = installSettings.value(kInstallSettingsKey).toString();
+            if (QDir::isRelativePath(newInstallSettingsPath))
+                newInstallSettingsPath = applicationDirPath() + '/' + newInstallSettingsPath;
+            QSettings::setPath(QSettings::IniFormat, QSettings::SystemScope, newInstallSettingsPath);
+        }
+        scope = QSettings::SystemScope; // UserScope only the first time we check
+        ++count;
+    } while (containsInstallSettingsKey && count < 3);
 }
 
 static Utils::QtcSettings *createUserSettings()
diff --git a/src/plugins/qtsupport/qtoptionspage.cpp b/src/plugins/qtsupport/qtoptionspage.cpp
index c0049058ab..9df0dd5068 100644
--- a/src/plugins/qtsupport/qtoptionspage.cpp
+++ b/src/plugins/qtsupport/qtoptionspage.cpp
@@ -897,9 +897,9 @@ void QtOptionsPageWidget::apply()
             &QtOptionsPageWidget::updateQtVersions);
 }
 
-// TODO whenever we move the output of sdktool to a different location in the installer,
-// this needs to be adapted accordingly
 const QStringList kSubdirsToCheck = {"",
+                                     "Tools/sdktool", // macOS
+                                     "Tools/sdktool/share/qtcreator", // Windows/Linux
                                      "Qt Creator.app/Contents/Resources",
                                      "Contents/Resources",
                                      "Tools/QtCreator/share/qtcreator",