From c0d6a80856375f5d0597ef23b15a170df2527649 Mon Sep 17 00:00:00 2001
From: tompng <tomoyapenguin@gmail.com>
Date: Mon, 9 Sep 2024 01:06:36 +0900
Subject: [PATCH] Change default completor from regexp to auto, try
 TypeCompletor and fallback to RegexpCompletor.

---
 lib/irb/context.rb              | 10 +++++-----
 lib/irb/init.rb                 |  2 +-
 test/irb/test_context.rb        |  2 ++
 test/irb/test_init.rb           |  9 ++++++---
 test/irb/test_type_completor.rb | 15 +++++++++++++++
 5 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/lib/irb/context.rb b/lib/irb/context.rb
index 668a823f5..9c7a90dc3 100644
--- a/lib/irb/context.rb
+++ b/lib/irb/context.rb
@@ -179,8 +179,8 @@ def use_loader=(val)
       case completor_type
       when :regexp
         return RegexpCompletor.new
-      when :type
-        completor = build_type_completor
+      when :type, nil
+        completor = build_type_completor(verbose: !!completor_type)
         return completor if completor
       else
         warn "Invalid value for IRB.conf[:COMPLETOR]: #{completor_type}"
@@ -189,17 +189,17 @@ def use_loader=(val)
       RegexpCompletor.new
     end
 
-    private def build_type_completor
+    private def build_type_completor(verbose: false)
       if RUBY_ENGINE == 'truffleruby'
         # Avoid SyntaxError. truffleruby does not support endless method definition yet.
-        warn 'TypeCompletor is not supported on TruffleRuby yet'
+        warn 'TypeCompletor is not supported on TruffleRuby yet' if verbose
         return
       end
 
       begin
         require 'repl_type_completor'
       rescue LoadError => e
-        warn "TypeCompletor requires `gem repl_type_completor`: #{e.message}"
+        warn "TypeCompletor requires `gem repl_type_completor`: #{e.message}" if verbose
         return
       end
 
diff --git a/lib/irb/init.rb b/lib/irb/init.rb
index 7dc08912e..d474bd41d 100644
--- a/lib/irb/init.rb
+++ b/lib/irb/init.rb
@@ -80,7 +80,7 @@ def IRB.init_config(ap_path)
     @CONF[:USE_SINGLELINE] = false unless defined?(ReadlineInputMethod)
     @CONF[:USE_COLORIZE] = (nc = ENV['NO_COLOR']).nil? || nc.empty?
     @CONF[:USE_AUTOCOMPLETE] = ENV.fetch("IRB_USE_AUTOCOMPLETE", "true") != "false"
-    @CONF[:COMPLETOR] = ENV.fetch("IRB_COMPLETOR", "regexp").to_sym
+    @CONF[:COMPLETOR] = ENV["IRB_COMPLETOR"]&.to_sym
     @CONF[:INSPECT_MODE] = true
     @CONF[:USE_TRACER] = false
     @CONF[:USE_LOADER] = false
diff --git a/test/irb/test_context.rb b/test/irb/test_context.rb
index 7ad8fd2fc..9fa23ccce 100644
--- a/test/irb/test_context.rb
+++ b/test/irb/test_context.rb
@@ -705,6 +705,8 @@ def test_irb_path_setter
     def test_build_completor
       verbose, $VERBOSE = $VERBOSE, nil
       original_completor = IRB.conf[:COMPLETOR]
+      IRB.conf[:COMPLETOR] = nil
+      assert_match /IRB::(Regexp|Type)Completor/, @context.send(:build_completor).class.name
       IRB.conf[:COMPLETOR] = :regexp
       assert_equal 'IRB::RegexpCompletor', @context.send(:build_completor).class.name
       IRB.conf[:COMPLETOR] = :unknown
diff --git a/test/irb/test_init.rb b/test/irb/test_init.rb
index 3e8d01c5c..e00db1f4c 100644
--- a/test/irb/test_init.rb
+++ b/test/irb/test_init.rb
@@ -169,7 +169,7 @@ def test_completor_environment_variable
 
       ENV['IRB_COMPLETOR'] = nil
       IRB.setup(__FILE__)
-      assert_equal(:regexp, IRB.conf[:COMPLETOR])
+      assert_equal(nil, IRB.conf[:COMPLETOR])
 
       ENV['IRB_COMPLETOR'] = 'regexp'
       IRB.setup(__FILE__)
@@ -193,10 +193,12 @@ def test_completor_environment_variable
 
     def test_completor_setup_with_argv
       orig_completor_conf = IRB.conf[:COMPLETOR]
+      orig_completor_env = ENV['IRB_COMPLETOR']
+      ENV['IRB_COMPLETOR'] = nil
 
-      # Default is :regexp
+      # Default value nil will try type completor and fallbacks to regexp without warning
       IRB.setup(__FILE__, argv: [])
-      assert_equal :regexp, IRB.conf[:COMPLETOR]
+      assert_equal nil, IRB.conf[:COMPLETOR]
 
       IRB.setup(__FILE__, argv: ['--type-completor'])
       assert_equal :type, IRB.conf[:COMPLETOR]
@@ -205,6 +207,7 @@ def test_completor_setup_with_argv
       assert_equal :regexp, IRB.conf[:COMPLETOR]
     ensure
       IRB.conf[:COMPLETOR] = orig_completor_conf
+      ENV['IRB_COMPLETOR'] = orig_completor_env
     end
 
     def test_noscript
diff --git a/test/irb/test_type_completor.rb b/test/irb/test_type_completor.rb
index 412d7c696..970fe3d3c 100644
--- a/test/irb/test_type_completor.rb
+++ b/test/irb/test_type_completor.rb
@@ -27,6 +27,21 @@ def empty_binding
       binding
     end
 
+    def test_build_completor
+      verbose, $VERBOSE = $VERBOSE, nil
+      original_completor = IRB.conf[:COMPLETOR]
+      workspace = IRB::WorkSpace.new(Object.new)
+      @context = IRB::Context.new(nil, workspace, TestInputMethod.new)
+      # Default (nil, auto) tries to use TypeCompletor
+      IRB.conf[:COMPLETOR] = nil
+      assert_equal 'IRB::TypeCompletor', @context.send(:build_completor).class.name
+      IRB.conf[:COMPLETOR] = :type
+      assert_equal 'IRB::TypeCompletor', @context.send(:build_completor).class.name
+    ensure
+      $VERBOSE = verbose
+      IRB.conf[:COMPLETOR] = original_completor
+    end
+
     def assert_completion(preposing, target, binding: empty_binding, include: nil, exclude: nil)
       raise ArgumentError if include.nil? && exclude.nil?
       candidates = @completor.completion_candidates(preposing, target, '', bind: binding)