Change: Filter duplicate paths from valid search path list. (#11363)

src/fileio.cpp

@@ -84,6 +84,8 @@ static bool IsValidSearchPath(Searchpath sp)
 static void FillValidSearchPaths(bool only_local_path)
 {
 	_valid_searchpaths.clear();
+
+	std::set<std::string> seen{};
 	for (Searchpath sp = SP_FIRST_DIR; sp < NUM_SEARCHPATHS; sp++) {
 		if (only_local_path) {
 			switch (sp) {
@@ -97,7 +99,11 @@ static void FillValidSearchPaths(bool only_local_path)
 			}
 		}
 
-		if (IsValidSearchPath(sp)) _valid_searchpaths.emplace_back(sp);
+		if (IsValidSearchPath(sp)) {
+			if (seen.count(_searchpaths[sp]) != 0) continue;
+			seen.insert(_searchpaths[sp]);
+			_valid_searchpaths.emplace_back(sp);
+		}
 	}
 }