Handle launcher-settings.json not being found in CK3 files (#2800) #patch

Sentry event ID: 72fdb08741464fb18c5435bb1f1d7caa

Author: IhateTrains

ImperatorToCK3/Configuration.cs

@@ -311,6 +311,7 @@ private void VerifyImperatorVersion(ConverterVersion converterVersion) {
 	private void VerifyCK3Version(ConverterVersion converterVersion) {
 		var path = Path.Combine(CK3Path, "launcher/launcher-settings.json");
 		CK3Version = GameVersion.ExtractVersionFromLauncher(path) ??
+		             GetCK3VersionFromTitusBranchFile() ??
 		             throw new ConverterException("CK3 version could not be determined.");
 
 		Logger.Info($"CK3 version: {CK3Version.ToShortString()}");
@@ -325,6 +326,20 @@ private void VerifyCK3Version(ConverterVersion converterVersion) {
 		}
 	}
 
+	private GameVersion? GetCK3VersionFromTitusBranchFile() {
+		var path = Path.Combine(CK3Path, "titus_branch.txt");
+
+		if (!File.Exists(path)) {
+			Logger.Warn("titus_branch.txt not found");
+			return null;
+		}
+
+		// The file contains the game version in the following format: release/X.Y.Z.
+		var versionStr = File.ReadAllText(path).Trim().Replace("release/", "");
+		var version = new GameVersion(versionStr);
+		return version;
+	}
+
 	public void DetectSpecificCK3Mods(ICollection<Mod> loadedMods) {
 		var tfeMod = loadedMods.FirstOrDefault(m => m.Name.StartsWith("The Fallen Eagle", StringComparison.Ordinal));
 		if (tfeMod is not null) {