[Server] Add per-run configuration overrides (#7820)

Add --set key=value to override a section-qualified scalar configuration key for a single run and --print-config to print the effective configuration, with secrets redacted. SettingsCache owns the override map, so reads see the override without rewriting the ini file, and rebuilds the disallowed-name regexps when users/disallowedregexp is overridden. Bare keys and array-scoped keys are rejected because array loops read them relative to the active group, where a full-key override would either be ignored or rewrite every entry.

Cover the ini, default, override, override-only-key, regexp-rebuild, secret-redaction, and parse paths with a server-labelled gtest.

tests/settings/servatrice_settings_test.cpp

@@ -0,0 +1,162 @@
+#include "settingscache.h"
+
+#include <QByteArray>
+#include <QCoreApplication>
+#include <QFile>
+#include <QSettings>
+#include <QString>
+#include <QTemporaryDir>
+#include <gtest/gtest.h>
+
+namespace
+{
+/**
+ * QSettings' path helpers and the portable-mode probe need a QCoreApplication.
+ * The test binary keeps one alive for the whole process.
+ */
+QCoreApplication &testApplication()
+{
+    static int argc = 1;
+    static char name[] = "servatrice_settings_test";
+    static char *argv[] = {name, nullptr};
+    static QCoreApplication application(argc, argv);
+    return application;
+}
+
+class ServatriceSettingsTest : public ::testing::Test
+{
+protected:
+    QTemporaryDir dir;
+
+    void SetUp() override
+    {
+        testApplication();
+        ASSERT_TRUE(dir.isValid());
+    }
+
+    QString configPath() const
+    {
+        return dir.filePath(QStringLiteral("servatrice.ini"));
+    }
+
+    void writeConfig(const QByteArray &contents) const
+    {
+        QFile file(configPath());
+        ASSERT_TRUE(file.open(QIODevice::WriteOnly | QIODevice::Text));
+        ASSERT_EQ(file.write(contents), contents.size());
+    }
+};
+} // namespace
+
+TEST_F(ServatriceSettingsTest, ReadsValueFromIni)
+{
+    writeConfig("[server]\nport=4747\n");
+    SettingsCache settings(configPath());
+
+    EXPECT_EQ(settings.value("server/port").toInt(), 4747);
+}
+
+TEST_F(ServatriceSettingsTest, MissingKeyFallsBackToDefault)
+{
+    writeConfig("[server]\nport=4747\n");
+    SettingsCache settings(configPath());
+
+    EXPECT_EQ(settings.value("server/missing", 1234).toInt(), 1234);
+}
+
+TEST_F(ServatriceSettingsTest, OverrideWinsWithoutTouchingTheFile)
+{
+    writeConfig("[server]\nport=4747\n");
+    SettingsCache settings(configPath());
+    settings.setOverride("server/port", 1234);
+
+    EXPECT_EQ(settings.value("server/port").toInt(), 1234);
+    // The base class still sees the file value: an override is per-run only.
+    EXPECT_EQ(static_cast<QSettings &>(settings).value("server/port").toInt(), 4747);
+}
+
+TEST_F(ServatriceSettingsTest, OverrideAppearsWhenKeyIsAbsentFromTheFile)
+{
+    writeConfig("[server]\nport=4747\n");
+    SettingsCache settings(configPath());
+    settings.setOverride("server/name", "override-only");
+
+    EXPECT_EQ(settings.value("server/name").toString(), QStringLiteral("override-only"));
+    EXPECT_FALSE(settings.allKeys().contains("server/name"));
+    EXPECT_TRUE(settings.getOverrides().contains("server/name"));
+}
+
+TEST_F(ServatriceSettingsTest, RebuildUsesTheOverriddenRegexpList)
+{
+    writeConfig("[users]\ndisallowedregexp=^bad$\n");
+    SettingsCache settings(configPath());
+    ASSERT_EQ(settings.disallowedRegExp.size(), 1);
+    EXPECT_TRUE(settings.disallowedRegExp.first().match("bad").hasMatch());
+
+    settings.setOverride("users/disallowedregexp", "^worse$");
+    settings.rebuildDisallowedRegExps();
+
+    ASSERT_EQ(settings.disallowedRegExp.size(), 1);
+    EXPECT_TRUE(settings.disallowedRegExp.first().match("worse").hasMatch());
+    EXPECT_FALSE(settings.disallowedRegExp.first().match("bad").hasMatch());
+}
+
+TEST_F(ServatriceSettingsTest, EffectiveKeysIncludeOverridesAndStaySorted)
+{
+    writeConfig("[server]\nport=4747\n");
+    SettingsCache settings(configPath());
+    settings.setOverride("server/name", "override-only");
+
+    const QStringList keys = settings.effectiveKeys();
+    EXPECT_TRUE(keys.contains("server/name"));
+    EXPECT_TRUE(keys.contains("server/port"));
+
+    QStringList sorted = keys;
+    sorted.sort();
+    EXPECT_EQ(keys, sorted);
+}
+
+TEST(ServatriceSettingsParsingTest, SecretKeysAreRecognised)
+{
+    EXPECT_TRUE(SettingsCache::isSecretKey("authentication/password"));
+    EXPECT_TRUE(SettingsCache::isSecretKey("database/password"));
+    EXPECT_TRUE(SettingsCache::isSecretKey("smtp/password"));
+    EXPECT_TRUE(SettingsCache::isSecretKey("security/legacy_backup_key"));
+    EXPECT_TRUE(SettingsCache::isSecretKey("server/apiSecret"));
+    EXPECT_FALSE(SettingsCache::isSecretKey("server/port"));
+}
+
+TEST(ServatriceSettingsParsingTest, ParseOverrideAcceptsScalarKeys)
+{
+    QString key;
+    QVariant value;
+
+    ASSERT_TRUE(SettingsCache::parseOverride("server/port=14747", key, value));
+    EXPECT_EQ(key, QStringLiteral("server/port"));
+    EXPECT_EQ(value.toString(), QStringLiteral("14747"));
+
+    // Only the first '=' separates the key; the rest belongs to the value.
+    ASSERT_TRUE(SettingsCache::parseOverride("server/name=a=b", key, value));
+    EXPECT_EQ(value.toString(), QStringLiteral("a=b"));
+}
+
+TEST(ServatriceSettingsParsingTest, ParseOverrideRejectsMalformedEntries)
+{
+    QString key;
+    QVariant value;
+
+    EXPECT_FALSE(SettingsCache::parseOverride("server/port", key, value));
+    EXPECT_FALSE(SettingsCache::parseOverride("=14747", key, value));
+    EXPECT_FALSE(SettingsCache::parseOverride("   =14747", key, value));
+}
+
+TEST(ServatriceSettingsParsingTest, ParseOverrideRejectsBareAndArrayScopedKeys)
+{
+    QString key;
+    QVariant value;
+
+    EXPECT_FALSE(SettingsCache::parseOverride("name=Kitchen", key, value));
+    EXPECT_FALSE(SettingsCache::parseOverride("rooms/roomlist/1/name=Kitchen", key, value));
+    EXPECT_FALSE(SettingsCache::parseOverride("rooms/roomlist/01/name=Kitchen", key, value));
+    EXPECT_FALSE(SettingsCache::parseOverride("rooms/roomlist/size=2", key, value));
+}