Fix IO.popen

core/io.rbs

@@ -2533,10 +2533,19 @@ class IO < Object
   #
   # Raises exceptions that IO.pipe and Kernel.spawn raise.
   #
-  def self.popen: (string cmd, ?string | int mode, ?path: string?, ?external_encoding: String | Encoding | nil, ?internal_encoding: String | Encoding | nil, ?encoding: String | Encoding | nil, ?textmode: boolish, ?binmode: boolish, ?autoclose: boolish, ?mode: String, ?unsetenv_others: boolish, ?pgroup: true | Integer, ?umask: Integer, ?in: Kernel::redirect_fd, ?out: Kernel::redirect_fd, ?err: Kernel::redirect_fd, ?close_others: boolish, ?chdir: String) -> instance
-                | (Hash[string, string?] env, string cmd, ?string | int mode, ?path: string?, ?external_encoding: String | Encoding | nil, ?internal_encoding: String | Encoding | nil, ?encoding: String | Encoding | nil, ?textmode: boolish, ?binmode: boolish, ?autoclose: boolish, ?mode: String, ?unsetenv_others: boolish, ?pgroup: true | Integer, ?umask: Integer, ?in: Kernel::redirect_fd, ?out: Kernel::redirect_fd, ?err: Kernel::redirect_fd, ?close_others: boolish, ?chdir: String) -> instance
-                | [X] (string cmd, ?string | int mode, ?path: string?, ?external_encoding: String | Encoding | nil, ?internal_encoding: String | Encoding | nil, ?encoding: String | Encoding | nil, ?textmode: boolish, ?binmode: boolish, ?autoclose: boolish, ?mode: String, ?unsetenv_others: boolish, ?pgroup: true | Integer, ?umask: Integer, ?in: Kernel::redirect_fd, ?out: Kernel::redirect_fd, ?err: Kernel::redirect_fd, ?close_others: boolish, ?chdir: String) { (instance) -> X } -> X
-                | [X] (Hash[string, string?] env, string cmd, ?string | int mode, ?path: string?, ?external_encoding: String | Encoding | nil, ?internal_encoding: String | Encoding | nil, ?encoding: String | Encoding | nil, ?textmode: boolish, ?binmode: boolish, ?autoclose: boolish, ?mode: String, ?unsetenv_others: boolish, ?pgroup: true | Integer, ?umask: Integer, ?in: Kernel::redirect_fd, ?out: Kernel::redirect_fd, ?err: Kernel::redirect_fd, ?close_others: boolish, ?chdir: String) { (instance) -> X } -> X
+  def self.popen: (string | cmd_array cmd, ?string | int mode, ?path: string?, ?external_encoding: String | Encoding | nil, ?internal_encoding: String | Encoding | nil, ?encoding: String | Encoding | nil, ?textmode: boolish, ?binmode: boolish, ?autoclose: boolish, ?mode: String, ?unsetenv_others: boolish, ?pgroup: true | Integer, ?umask: Integer, ?in: Kernel::redirect_fd, ?out: Kernel::redirect_fd, ?err: Kernel::redirect_fd, ?close_others: boolish, ?chdir: String) -> instance
+                | (Hash[string, string?] env, string | cmd_array cmd, ?string | int mode, ?path: string?, ?external_encoding: String | Encoding | nil, ?internal_encoding: String | Encoding | nil, ?encoding: String | Encoding | nil, ?textmode: boolish, ?binmode: boolish, ?autoclose: boolish, ?mode: String, ?unsetenv_others: boolish, ?pgroup: true | Integer, ?umask: Integer, ?in: Kernel::redirect_fd, ?out: Kernel::redirect_fd, ?err: Kernel::redirect_fd, ?close_others: boolish, ?chdir: String) -> instance
+                | [X] (string | cmd_array cmd, ?string | int mode, ?path: string?, ?external_encoding: String | Encoding | nil, ?internal_encoding: String | Encoding | nil, ?encoding: String | Encoding | nil, ?textmode: boolish, ?binmode: boolish, ?autoclose: boolish, ?mode: String, ?unsetenv_others: boolish, ?pgroup: true | Integer, ?umask: Integer, ?in: Kernel::redirect_fd, ?out: Kernel::redirect_fd, ?err: Kernel::redirect_fd, ?close_others: boolish, ?chdir: String) { (instance) -> X } -> X
+                | [X] (Hash[string, string?] env, string | cmd_array cmd, ?string | int mode, ?path: string?, ?external_encoding: String | Encoding | nil, ?internal_encoding: String | Encoding | nil, ?encoding: String | Encoding | nil, ?textmode: boolish, ?binmode: boolish, ?autoclose: boolish, ?mode: String, ?unsetenv_others: boolish, ?pgroup: true | Integer, ?umask: Integer, ?in: Kernel::redirect_fd, ?out: Kernel::redirect_fd, ?err: Kernel::redirect_fd, ?close_others: boolish, ?chdir: String) { (instance) -> X } -> X
+
+  # The command can be given as:
+  #
+  # * Array of string `["ruby", "-v"]`, or
+  # * Array of string with the first element of array `[["ruby", "RUBY"], "-v"]`
+  #
+  # But RBS cannot define such a type. So this is simply a union of `string` or `[String, String]`.
+  #
+  type cmd_array = array[string | [String, String]]
 
   # <!--
   #   rdoc-file=io.c

test/stdlib/IO_test.rb

@@ -52,6 +52,38 @@ def test_open
     end
   end
 
+  def ruby
+    ENV["RUBY"] || RbConfig.ruby
+  end
+
+  def test_popen
+    with_string("#{ruby} -v") do |command|
+      assert_send_type(
+        "(string) { (IO) -> nil } -> nil",
+        IO, :popen, command, &proc { nil }
+      )
+
+      assert_send_type(
+        "(Hash[String, String], string) { (IO) -> nil } -> nil",
+        IO, :popen, { "RUBYOPT" => "-I lib" }, command, &proc { nil }
+      )
+    end
+
+    with_string("ruby") do |ruby|
+      with_array(ruby, "-v") do |cmd|
+        assert_send_type(
+          "(array[string]) { (IO) -> nil } -> nil",
+          IO, :popen, cmd, &proc { nil }
+        )
+
+        assert_send_type(
+          "(Hash[String, String], array[string]) { (IO) -> nil } -> nil",
+          IO, :popen, { "RUBYOPT" => "-I lib" }, cmd, &proc { nil }
+        )
+      end
+    end
+  end
+
   def test_copy_stream
     Dir.mktmpdir do |dir|
       src_name = File.join(dir, "src_file").tap { |f| IO.write(f, "foo") }