Make `m_cached_blocks_path` mutable. Make `ArgsManager::GetBlocksDirPath()` const.

src/util/system.cpp

@@ -388,7 +388,7 @@ std::optional<unsigned int> ArgsManager::GetArgFlags(const std::string& name) co
     return std::nullopt;
 }
 
-const fs::path& ArgsManager::GetBlocksDirPath()
+const fs::path& ArgsManager::GetBlocksDirPath() const
 {
     LOCK(cs_args);
     fs::path& path = m_cached_blocks_path;

src/util/system.h

@@ -195,7 +195,7 @@ protected:
     std::map<OptionsCategory, std::map<std::string, Arg>> m_available_args GUARDED_BY(cs_args);
     bool m_accept_any_command GUARDED_BY(cs_args){true};
     std::list<SectionInfo> m_config_sections GUARDED_BY(cs_args);
-    fs::path m_cached_blocks_path GUARDED_BY(cs_args);
+    mutable fs::path m_cached_blocks_path GUARDED_BY(cs_args);
     mutable fs::path m_cached_datadir_path GUARDED_BY(cs_args);
     mutable fs::path m_cached_network_datadir_path GUARDED_BY(cs_args);
 
@@ -266,7 +266,7 @@ public:
      *
      * @return Blocks path which is network specific
      */
-    const fs::path& GetBlocksDirPath();
+    const fs::path& GetBlocksDirPath() const;
 
     /**
      * Get data directory path