Deprecate Kernel#open and IO support for subprocess creation/forking

Deprecate Kernel#open and IO support for subprocess creation and
forking. This deprecates subprocess creation and forking in

- Kernel#open
- URI.open
- IO.binread
- IO.foreach
- IO.readlines
- IO.read
- IO.write

This behavior is slated to be removed in Ruby 4.0

[Feature #19630]

1 files changed, 19 insertions, 8 deletions

diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index aad1530588..7689b52e23 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -2412,15 +2412,19 @@ class TestIO < Test::Unit::TestCase
   end
 
   def test_open_pipe
-    open("|" + EnvUtil.rubybin, "r+") do |f|
-      f.puts "puts 'foo'"
-      f.close_write
-      assert_equal("foo\n", f.read)
+    assert_deprecated_warning(/Kernel#open with a leading '\|'/) do # https://bugs.ruby-lang.org/issues/19630
+      open("|" + EnvUtil.rubybin, "r+") do |f|
+        f.puts "puts 'foo'"
+        f.close_write
+        assert_equal("foo\n", f.read)
+      end
     end
   end
 
   def test_read_command
-    assert_equal("foo\n", IO.read("|echo foo"))
+    assert_deprecated_warning(/IO process creation with a leading '\|'/) do # https://bugs.ruby-lang.org/issues/19630
+      assert_equal("foo\n", IO.read("|echo foo"))
+    end
     assert_raise(Errno::ENOENT, Errno::EINVAL) do
       File.read("|#{EnvUtil.rubybin} -e puts")
     end
@@ -2434,7 +2438,9 @@ class TestIO < Test::Unit::TestCase
       Class.new(IO).binread("|#{EnvUtil.rubybin} -e puts")
     end
     assert_raise(Errno::ESPIPE) do
-      IO.read("|echo foo", 1, 1)
+      assert_deprecated_warning(/IO process creation with a leading '\|'/) do # https://bugs.ruby-lang.org/issues/19630
+        IO.read("|echo foo", 1, 1)
+      end
     end
   end
 
@@ -2619,11 +2625,16 @@ class TestIO < Test::Unit::TestCase
 
   def test_foreach
     a = []
-    IO.foreach("|" + EnvUtil.rubybin + " -e 'puts :foo; puts :bar; puts :baz'") {|x| a << x }
+
+    assert_deprecated_warning(/IO process creation with a leading '\|'/) do # https://bugs.ruby-lang.org/issues/19630
+      IO.foreach("|" + EnvUtil.rubybin + " -e 'puts :foo; puts :bar; puts :baz'") {|x| a << x }
+    end
     assert_equal(["foo\n", "bar\n", "baz\n"], a)
 
     a = []
-    IO.foreach("|" + EnvUtil.rubybin + " -e 'puts :zot'", :open_args => ["r"]) {|x| a << x }
+    assert_deprecated_warning(/IO process creation with a leading '\|'/) do # https://bugs.ruby-lang.org/issues/19630
+      IO.foreach("|" + EnvUtil.rubybin + " -e 'puts :zot'", :open_args => ["r"]) {|x| a << x }
+    end
     assert_equal(["zot\n"], a)
 
     make_tempfile {|t|