[ruby/reline] Drop loading terminfo, remove fiddle dependency in

non-windows environment.
(ruby/reline#769)

Reline works perfectly in most major terminal emulators without terminfo.
In minor/old terminal emulator, we used to get key bindings from terminfo, but I think it is not used so much.

ruby/reline@3ceba3bff7

Author: tompng

lib/reline.rb

@@ -6,7 +6,6 @@
 require 'reline/key_stroke'
 require 'reline/line_editor'
 require 'reline/history'
-require 'reline/terminfo'
 require 'reline/io'
 require 'reline/face'
 require 'rbconfig'

lib/reline/io/ansi.rb

@@ -29,10 +29,6 @@ class Reline::ANSI < Reline::IO
     'H' => [:ed_move_to_beg, {}],
   }
 
-  if Reline::Terminfo.enabled?
-    Reline::Terminfo.setupterm(0, 2)
-  end
-
   def initialize
     @input = STDIN
     @output = STDOUT
@@ -44,14 +40,10 @@ def encoding
     @input.external_encoding || Encoding.default_external
   end
 
-  def set_default_key_bindings(config, allow_terminfo: true)
+  def set_default_key_bindings(config)
     set_bracketed_paste_key_bindings(config)
     set_default_key_bindings_ansi_cursor(config)
-    if allow_terminfo && Reline::Terminfo.enabled?
-      set_default_key_bindings_terminfo(config)
-    else
-      set_default_key_bindings_comprehensive_list(config)
-    end
+    set_default_key_bindings_comprehensive_list(config)
     {
       [27, 91, 90] => :completion_journey_up, # S-Tab
     }.each_pair do |key, func|
@@ -98,23 +90,6 @@ def set_default_key_bindings_ansi_cursor(config)
     end
   end
 
-  def set_default_key_bindings_terminfo(config)
-    key_bindings = CAPNAME_KEY_BINDINGS.map do |capname, key_binding|
-      begin
-        key_code = Reline::Terminfo.tigetstr(capname)
-        [ key_code.bytes, key_binding ]
-      rescue Reline::Terminfo::TerminfoError
-        # capname is undefined
-      end
-    end.compact.to_h
-
-    key_bindings.each_pair do |key, func|
-      config.add_default_key_binding_by_keymap(:emacs, key, func)
-      config.add_default_key_binding_by_keymap(:vi_insert, key, func)
-      config.add_default_key_binding_by_keymap(:vi_command, key, func)
-    end
-  end
-
   def set_default_key_bindings_comprehensive_list(config)
     {
       # xterm
@@ -281,27 +256,11 @@ def move_cursor_down(x)
   end
 
   def hide_cursor
-    seq = "\e[?25l"
-    if Reline::Terminfo.enabled? && Reline::Terminfo.term_supported?
-      begin
-        seq = Reline::Terminfo.tigetstr('civis')
-      rescue Reline::Terminfo::TerminfoError
-        # civis is undefined
-      end
-    end
-    @output.write seq
+    @output.write "\e[?25l"
   end
 
   def show_cursor
-    seq = "\e[?25h"
-    if Reline::Terminfo.enabled? && Reline::Terminfo.term_supported?
-      begin
-        seq = Reline::Terminfo.tigetstr('cnorm')
-      rescue Reline::Terminfo::TerminfoError
-        # cnorm is undefined
-      end
-    end
-    @output.write seq
+    @output.write "\e[?25h"
   end
 
   def erase_after_cursor

lib/reline/terminfo.rb

@@ -1,11 +1,11 @@
 require_relative 'helper'
 require 'reline'
 
-class Reline::ANSI::WithoutTerminfoTest < Reline::TestCase
+class Reline::ANSITest < Reline::TestCase
   def setup
     Reline.send(:test_mode, ansi: true)
     @config = Reline::Config.new
-    Reline.core.io_gate.set_default_key_bindings(@config, allow_terminfo: false)
+    Reline.core.io_gate.set_default_key_bindings(@config)
   end
 
   def teardown
@@ -50,7 +50,7 @@ def test_left_arrow
     assert_key_binding("\eOD", :ed_prev_char)
   end
 
-  # Ctrl+arrow and Meta+arrow; always mapped regardless of terminfo enabled or not
+  # Ctrl+arrow and Meta+arrow
   def test_extended
     assert_key_binding("\e[1;5C", :em_next_word) # Ctrl+→
     assert_key_binding("\e[1;5D", :ed_prev_word) # Ctrl+←
@@ -60,12 +60,11 @@ def test_extended
     assert_key_binding("\e\e[D", :ed_prev_word) # Meta+←
   end
 
-  # Shift-Tab; always mapped regardless of terminfo enabled or not
   def test_shift_tab
     assert_key_binding("\e[Z", :completion_journey_up, [:emacs, :vi_insert])
   end
 
-  # A few emacs bindings that are always mapped regardless of terminfo enabled or not
+  # A few emacs bindings that are always mapped
   def test_more_emacs
     assert_key_binding("\e ", :em_set_mark, [:emacs])
     assert_key_binding("\C-x\C-x", :em_exchange_mark, [:emacs])