Reline::ANSI is general io. Reline::GeneralIO is not.

Reline::ANSI has a partial non-tty supporting code. It should be a general io.
Reline::GeneralIO should be renamed because it is actually not a general io but an unusable io only for test usage.

lib/reline.rb

@@ -263,7 +263,6 @@ def readmultiline(prompt = '', add_hist = false, &confirm_multiline_termination)
           raise ArgumentError.new('#readmultiline needs block to confirm multiline termination')
         end
 
-        Reline.update_iogate
         io_gate.with_raw_input do
           inner_readline(prompt, add_hist, true, &confirm_multiline_termination)
         end
@@ -286,7 +285,6 @@ def readmultiline(prompt = '', add_hist = false, &confirm_multiline_termination)
 
     def readline(prompt = '', add_hist = false)
       @mutex.synchronize do
-        Reline.update_iogate
         io_gate.with_raw_input do
           inner_readline(prompt, add_hist, false)
         end
@@ -336,7 +334,7 @@ def readline(prompt = '', add_hist = false)
       line_editor.auto_indent_proc = auto_indent_proc
       line_editor.dig_perfect_match_proc = dig_perfect_match_proc
       pre_input_hook&.call
-      unless Reline::IOGate == Reline::GeneralIO
+      unless Reline::IOGate == Reline::TestDumbIO
         @dialog_proc_list.each_pair do |name_sym, d|
           line_editor.add_dialog_proc(name_sym, d.dialog_proc, d.context)
         end
@@ -473,7 +471,7 @@ def ambiguous_width
     end
 
     private def may_req_ambiguous_char_width
-      @ambiguous_width = 2 if io_gate == Reline::GeneralIO or !STDOUT.tty?
+      @ambiguous_width = 2 if io_gate == Reline::TestDumbIO || !STDIN.tty? || !STDOUT.tty?
       return if defined? @ambiguous_width
       io_gate.move_cursor_column(0)
       begin
@@ -567,38 +565,25 @@ def self.ungetc(c)
   def self.line_editor
     core.line_editor
   end
-
-  def self.update_iogate
-    return if core.config.test_mode
-
-    # Need to change IOGate when `$stdout.tty?` change from false to true by `$stdout.reopen`
-    # Example: rails/spring boot the application in non-tty, then run console in tty.
-    if ENV['TERM'] != 'dumb' && core.io_gate == Reline::GeneralIO && $stdout.tty?
-      require 'reline/ansi'
-      remove_const(:IOGate)
-      const_set(:IOGate, Reline::ANSI)
-    end
-  end
 end
 
-require 'reline/general_io'
-io = Reline::GeneralIO
-unless ENV['TERM'] == 'dumb'
-  case RbConfig::CONFIG['host_os']
-  when /mswin|msys|mingw|cygwin|bccwin|wince|emc/
-    require 'reline/windows'
-    tty = (io = Reline::Windows).msys_tty?
-  else
-    tty = $stdout.tty?
-  end
+require 'reline/test_dumb_io'
+Reline::GeneralIO = Reline::TestDumbIO
+Reline.deprecate_constant :GeneralIO
+
+if ENV['TERM'] == 'dumb'
+  io = Reline::TestDumbIO
+elsif /mswin|msys|mingw|cygwin|bccwin|wince|emc/.match?(RbConfig::CONFIG['host_os'])
+  require 'reline/windows'
+  io = Reline::Windows unless Reline::Windows.msys_tty?
 end
-Reline::IOGate = if tty
+unless io
   require 'reline/ansi'
-  Reline::ANSI
-else
-  io
+  io = Reline::ANSI
 end
 
+Reline::IOGate = io
+
 Reline::Face.load_initial_configs
 
 Reline::HISTORY = Reline::History.new(Reline.core.config)

lib/reline/ansi.rb

@@ -177,12 +177,10 @@ def self.inner_getc(timeout_second)
       Reline.core.line_editor.handle_signal
     end
     c = @@input.getbyte
-    (c == 0x16 && @@input.raw(min: 0, time: 0, &:getbyte)) || c
+    (c == 0x16 && @@input.tty? && @@input.raw(min: 0, time: 0, &:getbyte)) || c
   rescue Errno::EIO
     # Maybe the I/O has been closed.
     nil
-  rescue Errno::ENOTTY
-    nil
   end
 
   START_BRACKETED_PASTE = String.new("\e[200~", encoding: Encoding::ASCII_8BIT)
@@ -242,12 +240,12 @@ def self.get_screen_size
   def self.set_screen_size(rows, columns)
     @@input.winsize = [rows, columns]
     self
-  rescue Errno::ENOTTY
+  rescue Errno::ENOTTY, Errno::ENODEV
     self
   end
 
   def self.cursor_pos
-    begin
+    if @@input.tty? && @@output.tty?
       res = +''
       m = nil
       @@input.raw do |stdin|
@@ -266,7 +264,7 @@ def self.cursor_pos
       end
       column = m[:column].to_i - 1
       row = m[:row].to_i - 1
-    rescue Errno::ENOTTY
+    else
       begin
         buf = @@output.pread(@@output.pos, 0)
         row = buf.count("\n")

lib/reline/line_editor.rb

@@ -459,6 +459,7 @@ def update_dialogs(key = nil)
   def render_finished
     clear_rendered_lines
     render_full_content
+    @output.flush
   end
 
   def clear_rendered_lines
@@ -553,6 +554,7 @@ def render_differential
     Reline::IOGate.move_cursor_column wrapped_cursor_x
     Reline::IOGate.move_cursor_down y - cursor_y
     @rendered_screen.cursor_y = y
+    @output.flush
     new_lines.size - y
   end
 

lib/reline/general_io.rb → lib/reline/test_dumb_io.rb

@@ -1,6 +1,6 @@
 require 'io/wait'
 
-class Reline::GeneralIO
+class Reline::TestDumbIO
   RESET_COLOR = '' # Do not send color reset sequence
 
   def self.reset(encoding: nil)

test/reline/helper.rb

@@ -23,7 +23,7 @@ class <<self
     def test_mode(ansi: false)
       @original_iogate = IOGate
       remove_const('IOGate')
-      const_set('IOGate', ansi ? Reline::ANSI : Reline::GeneralIO)
+      const_set('IOGate', ansi ? Reline::ANSI : Reline::TestDumbIO)
       if ENV['RELINE_TEST_ENCODING']
         encoding = Encoding.find(ENV['RELINE_TEST_ENCODING'])
       else
@@ -34,7 +34,7 @@ def test_mode(ansi: false)
       def IOGate.get_screen_size
         [24, 80]
       end
-      Reline::GeneralIO.reset(encoding: encoding) unless ansi
+      Reline::TestDumbIO.reset(encoding: encoding) unless ansi
       core.config.instance_variable_set(:@test_mode, true)
       core.config.reset
     end
@@ -44,7 +44,7 @@ def test_reset
       IOGate.define_singleton_method(:get_screen_size, @original_get_screen_size)
       remove_const('IOGate')
       const_set('IOGate', @original_iogate)
-      Reline::GeneralIO.reset
+      Reline::TestDumbIO.reset
       Reline.instance_variable_set(:@core, nil)
     end
 
@@ -146,7 +146,7 @@ def assert_byte_pointer_size(expected)
       expected.bytesize, byte_pointer,
       <<~EOM)
         <#{expected.inspect} (#{expected.encoding.inspect})> expected but was
-        <#{chunk.inspect} (#{chunk.encoding.inspect})> in <Terminal #{Reline::GeneralIO.encoding.inspect}>
+        <#{chunk.inspect} (#{chunk.encoding.inspect})> in <Terminal #{Reline::TestDumbIO.encoding.inspect}>
       EOM
   end
 

test/reline/test_reline.rb

@@ -375,7 +375,7 @@ def test_read_io
   def test_dumb_terminal
     lib = File.expand_path("../../lib", __dir__)
     out = IO.popen([{"TERM"=>"dumb"}, Reline.test_rubybin, "-I#{lib}", "-rreline", "-e", "p Reline.core.io_gate"], &:read)
-    assert_equal("Reline::GeneralIO", out.chomp)
+    assert_equal("Reline::TestDumbIO", out.chomp)
   end
 
   def test_require_reline_should_not_trigger_winsize