Don't use CK3 titles under h_china for mapping I:R governorships (#3022)

Author: IhateTrains

ImperatorToCK3/CK3/Titles/Title.cs

@@ -1438,6 +1438,17 @@ public Title GetTopRealm(Date date) {
 		return null;
 	}
 
+	internal Title? GetDeJureLiegeOfRank(TitleRank rank) {
+		// For rank equal to the title's rank, return the title itself.
+		if (Rank == rank) {
+			return this;
+		}
+		if (DeJureLiege is null) {
+			return null;
+		}
+		return DeJureLiege.GetDeJureLiegeOfRank(rank);
+	}
+
 	public static TitleRank GetRankForId(string titleId) {
 		var firstChar = titleId[0];
 		return firstChar switch {

ImperatorToCK3/Mappers/TagTitle/TagTitleMapper.cs

@@ -98,7 +98,7 @@ public void RegisterGovernorship(string imperatorRegion, string imperatorCountry
 		}
 
 		// Attempt a title match
-		foreach (var mapping in titleMappings) {
+		foreach (var mapping in titleMappings.ToArray()) {
 			var match = mapping.GovernorshipMatch(rank, titles, governorship, provMapper, irProvinces);
 			if (match is null) {
 				continue;
@@ -107,6 +107,15 @@ public void RegisterGovernorship(string imperatorRegion, string imperatorCountry
 			if (usedTitles.Contains(match)) {
 				continue;
 			}
+
+			// Currently we don't want to modify the de jure structure of h_china.
+			// So, if the given title ID belongs to h_china de jure hierarchy, we skip it and remove the mapping.
+			if (titles.TryGetValue(match, out var ck3Title) && ck3Title.GetDeJureLiegeOfRank(TitleRank.hegemony)?.Id == "h_china") {
+				Logger.Debug($"Governorship title {match} belongs to h_china de jure hierarchy! Skipping mapping for governorship in region {governorship.Region.Id} of country {country.Tag}.");
+				titleMappings.Remove(mapping);
+				continue;
+			}
+
 			RegisterGovernorship(governorship.Region.Id, country.Tag, match);
 			return match;
 		}