irb.rb: preserve ARGV on binding.irb

This is not perfectly good solution (at least we don't want to have ARGV
as default value of `argv` argument), but unfortunately IRB.setup and
IRB.parse_opts are public methods and we can't make breaking change to
those methods.

We may deprecate using them and then make them private in the future,
but the removal should not be in Ruby 2.5. So I kept their interface for
now.

[Bug #14162] [close GH-1770]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61149 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/irb.rb

@@ -704,7 +704,7 @@ end
 class Binding
   # :nodoc:
   def irb
-    IRB.setup(eval("__FILE__"))
+    IRB.setup(eval("__FILE__"), argv: [])
     workspace = IRB::WorkSpace.new(self)
     STDOUT.print(workspace.code_around_binding)
     IRB::Irb.new(workspace).run(IRB.conf)

lib/irb/init.rb

@@ -13,10 +13,10 @@
 module IRB # :nodoc:
 
   # initialize config
-  def IRB.setup(ap_path)
+  def IRB.setup(ap_path, argv: ARGV)
     IRB.init_config(ap_path)
     IRB.init_error
-    IRB.parse_opts
+    IRB.parse_opts(argv: argv)
     IRB.run_config
     IRB.load_modules
 
@@ -121,9 +121,9 @@ module IRB # :nodoc:
   end
 
   # option analyzing
-  def IRB.parse_opts
+  def IRB.parse_opts(argv: ARGV)
     load_path = []
-    while opt = ARGV.shift
+    while opt = argv.shift
       case opt
       when "-f"
         @CONF[:RC] = false
@@ -133,7 +133,7 @@ module IRB # :nodoc:
       when "-w"
         $VERBOSE = true
       when /^-W(.+)?/
-        opt = $1 || ARGV.shift
+        opt = $1 || argv.shift
         case opt
         when "0"
           $VERBOSE = nil
@@ -143,19 +143,19 @@ module IRB # :nodoc:
           $VERBOSE = true
         end
       when /^-r(.+)?/
-        opt = $1 || ARGV.shift
+        opt = $1 || argv.shift
         @CONF[:LOAD_MODULES].push opt if opt
       when /^-I(.+)?/
-        opt = $1 || ARGV.shift
+        opt = $1 || argv.shift
         load_path.concat(opt.split(File::PATH_SEPARATOR)) if opt
       when '-U'
         set_encoding("UTF-8", "UTF-8")
       when /^-E(.+)?/, /^--encoding(?:=(.+))?/
-        opt = $1 || ARGV.shift
+        opt = $1 || argv.shift
         set_encoding(*opt.split(':', 2))
       when "--inspect"
-        if /^-/ !~ ARGV.first
-          @CONF[:INSPECT_MODE] = ARGV.shift
+        if /^-/ !~ argv.first
+          @CONF[:INSPECT_MODE] = argv.shift
         else
           @CONF[:INSPECT_MODE] = true
         end
@@ -174,7 +174,7 @@ module IRB # :nodoc:
       when "--noverbose"
         @CONF[:VERBOSE] = false
       when /^--prompt-mode(?:=(.+))?/, /^--prompt(?:=(.+))?/
-        opt = $1 || ARGV.shift
+        opt = $1 || argv.shift
         prompt_mode = opt.upcase.tr("-", "_").intern
         @CONF[:PROMPT_MODE] = prompt_mode
       when "--noprompt"
@@ -186,13 +186,13 @@ module IRB # :nodoc:
       when "--tracer"
         @CONF[:USE_TRACER] = true
       when /^--back-trace-limit(?:=(.+))?/
-        @CONF[:BACK_TRACE_LIMIT] = ($1 || ARGV.shift).to_i
+        @CONF[:BACK_TRACE_LIMIT] = ($1 || argv.shift).to_i
       when /^--context-mode(?:=(.+))?/
-        @CONF[:CONTEXT_MODE] = ($1 || ARGV.shift).to_i
+        @CONF[:CONTEXT_MODE] = ($1 || argv.shift).to_i
       when "--single-irb"
         @CONF[:SINGLE_IRB] = true
       when /^--irb_debug(?:=(.+))?/
-        @CONF[:DEBUG_LEVEL] = ($1 || ARGV.shift).to_i
+        @CONF[:DEBUG_LEVEL] = ($1 || argv.shift).to_i
       when "-v", "--version"
         print IRB.version, "\n"
         exit 0
@@ -201,7 +201,7 @@ module IRB # :nodoc:
         IRB.print_usage
         exit 0
       when "--"
-        if opt = ARGV.shift
+        if opt = argv.shift
           @CONF[:SCRIPT] = opt
           $0 = opt
         end

test/irb/test_init.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: false
+require "test/unit"
+require "irb"
+
+module TestIRB
+  class TestInit < Test::Unit::TestCase
+    def test_setup_with_argv_preserves_global_argv
+      argv = ["foo", "bar"]
+      with_argv(argv) do
+        IRB.setup(eval("__FILE__"), argv: [])
+        assert_equal argv, ARGV
+      end
+    end
+
+    private
+
+    def with_argv(argv)
+      orig = ARGV.dup
+      ARGV.replace(argv)
+      yield
+    ensure
+      ARGV.replace(orig)
+    end
+  end
+end