fix hitory file path

* Set `CONFIG[:history_file]` as nil, and ignore it if it is nil.
* Respect `CONFIG[:history_file]` even if the path doesn't exists.
* Respect `~/.rdbg_history` if exists for compatibility.
* Use `XDG_STATE_HOME` if there is no configuration about history file.

Author: ko1

README.md

@@ -512,7 +512,7 @@ config set no_color true
   * `RUBY_DEBUG_INIT_SCRIPT` (`init_script`): debug command script path loaded at first stop
   * `RUBY_DEBUG_COMMANDS` (`commands`): debug commands invoked at first stop. Commands should be separated by `;;`
   * `RUBY_DEBUG_NO_RC` (`no_rc`): ignore loading ~/.rdbgrc(.rb) (default: false)
-  * `RUBY_DEBUG_HISTORY_FILE` (`history_file`): history file (default: ~/.rdbg_history)
+  * `RUBY_DEBUG_HISTORY_FILE` (`history_file`): history file (default: $XDG_STATE_HOME/rdbg/history)
   * `RUBY_DEBUG_SAVE_HISTORY` (`save_history`): maximum save history lines (default: 10000)
 
 * REMOTE

lib/debug/config.rb

@@ -40,7 +40,7 @@ module DEBUGGER__
     init_script:         ['RUBY_DEBUG_INIT_SCRIPT', "BOOT: debug command script path loaded at first stop"],
     commands:            ['RUBY_DEBUG_COMMANDS',    "BOOT: debug commands invoked at first stop. Commands should be separated by `;;`"],
     no_rc:               ['RUBY_DEBUG_NO_RC',       "BOOT: ignore loading ~/.rdbgrc(.rb)",                               :bool, "false"],
-    history_file:        ['RUBY_DEBUG_HISTORY_FILE',"BOOT: history file",               :string, "~/.rdbg_history"],
+    history_file:        ['RUBY_DEBUG_HISTORY_FILE',"BOOT: history file (default: $XDG_STATE_HOME/rdbg/history)",        :string, nil],
     save_history:        ['RUBY_DEBUG_SAVE_HISTORY',"BOOT: maximum save history lines", :int, "10000"],
 
     # remote setting

lib/debug/console.rb

@@ -153,26 +153,24 @@ def history
     end
 
     def history_file
-      path =
-        if !CONFIG[:history_file].empty? && File.exist?(File.expand_path(CONFIG[:history_file]))
-          CONFIG[:history_file]
-        elsif (xdg_home = ENV['XDG_DATA_HOME'])
-          File.join(xdg_home, 'rdbg', 'history')
-        else
-          '~/.rdbg_history'
-        end
-
-      path = File.expand_path(path)
+      case
+      when (path = CONFIG[:history_file]) && !path.empty?
+        path = File.expand_path(path)
+      when (path = File.expand_path("~/.rdbg_history")) && File.exist?(path) # for compatibility
+        # path
+      else
+        state_dir = ENV['XDG_STATE_HOME'] || File.join(Dir.home, '.local', 'state')
+        path = File.join(File.expand_path(state_dir), 'rdbg', 'history')
+      end
 
       FileUtils.mkdir_p(File.dirname(path)) unless File.exist?(path)
-
       path
     end
 
     FH = "# Today's OMIKUJI: "
 
     def read_history_file
-      if history && File.exist?(path = history_file)
+      if history && File.exist?(path = history_file())
         f = (['', 'DAI-', 'CHU-', 'SHO-'].map{|e| e+'KICHI'}+['KYO']).sample
         # Read history file and scrub invalid characters to prevent encoding errors
         lines = File.readlines(path).map(&:scrub)
@@ -195,12 +193,12 @@ def load_history_if_not_loaded
     def deactivate
       if history && @init_history_lines
         added_records = history.to_a[@init_history_lines .. -1]
-        path = history_file
+        path = history_file()
         max = CONFIG[:save_history]
 
         if !added_records.empty? && !path.empty?
           orig_records = read_history_file
-          open(history_file, 'w'){|f|
+          open(history_file(), 'w'){|f|
             (orig_records + added_records).last(max).each{|line|
               # Use scrub to handle encoding issues gracefully
               scrubbed_line = line.scrub.strip