From 458d98a279f95b91590809c8e1800038f1a47131 Mon Sep 17 00:00:00 2001
From: Martchus <martchus@gmx.net>
Date: Sat, 14 Oct 2023 20:44:59 +0200
Subject: [PATCH] Allow logging a few useful Qt-related information by setting
 env variable

Log Qt-related info when the environment variable
QT_UTILITIES_LOG_QT_CONFIG is set.
---
 settingsdialog/qtsettings.cpp | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/settingsdialog/qtsettings.cpp b/settingsdialog/qtsettings.cpp
index c0015d9..6fd10a3 100644
--- a/settingsdialog/qtsettings.cpp
+++ b/settingsdialog/qtsettings.cpp
@@ -12,14 +12,19 @@
 
 #include "../misc/desktoputils.h"
 
+#include "resources/config.h"
+
 #include "ui_qtappearanceoptionpage.h"
 #include "ui_qtenvoptionpage.h"
 #include "ui_qtlanguageoptionpage.h"
 
+#include <c++utilities/application/commandlineutils.h>
+
 #include <QDir>
 #include <QFileDialog>
 #include <QFontDialog>
 #include <QIcon>
+#include <QOperatingSystemVersion>
 #include <QSettings>
 #include <QStringBuilder>
 #include <QStyleFactory>
@@ -338,6 +343,24 @@ void QtSettings::apply()
     // apply locale
     m_d->previousLocale = QLocale();
     QLocale::setDefault(m_d->customLocale ? QLocale(m_d->localeName) : m_d->defaultLocale);
+
+    // log some debug information on the first call if env variable set
+    static auto debugInfoLogged = false;
+    if (debugInfoLogged) {
+        return;
+    }
+    const auto debugLoggingEnabled = CppUtilities::isEnvVariableSet(PROJECT_VARNAME_UPPER "_LOG_QT_CONFIG");
+    if (debugLoggingEnabled.has_value() && debugLoggingEnabled.value()) {
+        if (const auto os = QOperatingSystemVersion::current(); os.type() != QOperatingSystemVersion::Unknown) {
+            std::cerr << "OS name and version: " << os.name().toStdString() << ' ' << os.version().toString().toStdString() << '\n';
+        }
+        std::cerr << "Qt version: " << qVersion() << '\n';
+        std::cerr << "Qt platform (set QT_QPA_PLATFORM to override): " << QGuiApplication::platformName().toStdString() << '\n';
+        std::cerr << "Qt locale: " << QLocale().name().toStdString() << '\n';
+        std::cerr << "Qt library paths: " << QCoreApplication::libraryPaths().join(':').toStdString() << '\n';
+        std::cerr << "Qt theme search paths: " << QIcon::themeSearchPaths().join(':').toStdString() << '\n';
+        debugInfoLogged = true;
+    }
 }
 
 /*!