process.c: defaults to close_others false

Arbitrarily closing file descriptors on exec breaks use cases
where a Ruby process sets up a descriptor for non-Ruby children
to use.  For example, the "rake foo" target may spawn any number
of subprocesses (Ruby or not) which depends on parsing the "FOO"
environment variable for out_fd:99 and writing to foo.out

    FOO=out_fd:99 rake foo 99>>foo.out

Unfortunately, this introduced one incompatibility in
test/lib/test/unit.rb and it now requires explicitly setting
IO#close_on_exec=true

[ruby-core:88007] [Misc #14907]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64399 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 11 insertions, 0 deletions

diff --git a/test/lib/test/unit.rb b/test/lib/test/unit.rb
index 51c8960c52..7a09466d1c 100644
--- a/test/lib/test/unit.rb
+++ b/test/lib/test/unit.rb
@@ -145,6 +145,8 @@ module Test
             r.close if r
             nil
           else
+            r.close_on_exec = true
+            w.close_on_exec = true
             @jobserver = [r, w]
             options[:parallel] ||= 1
           end
diff --git a/test/ruby/test_process.rb b/test/ruby/test_process.rb
index a0b08dd110..bb56834dc0 100644
--- a/test/ruby/test_process.rb
+++ b/test/ruby/test_process.rb
@@ -1009,6 +1009,15 @@ class TestProcess < Test::Unit::TestCase
     }
   end
 
+  def test_close_others_default_false
+    IO.pipe do |r,w|
+      w.close_on_exec = false
+      src = "IO.new(#{w.fileno}).puts(:hi)"
+      assert_equal true, system(*%W(#{RUBY} --disable=gems -e #{src}))
+      assert_equal "hi\n", r.gets
+    end
+  end
+
   def test_execopts_redirect_self
     begin
       with_pipe {|r, w|