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, 28 insertions, 8 deletions

diff --git a/spec/ruby/core/kernel/open_spec.rb b/spec/ruby/core/kernel/open_spec.rb
index 99793294c5..bb42c31f31 100644
--- a/spec/ruby/core/kernel/open_spec.rb
+++ b/spec/ruby/core/kernel/open_spec.rb
@@ -29,7 +29,9 @@ describe "Kernel#open" do
 
   platform_is_not :windows, :wasi do
     it "opens an io when path starts with a pipe" do
-      @io = open("|date")
+      suppress_warning do # https://bugs.ruby-lang.org/issues/19630
+        @io = open("|date")
+      end
       begin
         @io.should be_kind_of(IO)
         @io.read
@@ -39,21 +41,27 @@ describe "Kernel#open" do
     end
 
     it "opens an io when called with a block" do
-      @output = open("|date") { |f| f.read }
+      suppress_warning do # https://bugs.ruby-lang.org/issues/19630
+        @output = open("|date") { |f| f.read }
+      end
       @output.should_not == ''
     end
 
     it "opens an io for writing" do
-      -> do
-        bytes = open("|cat", "w") { |io| io.write(".") }
-        bytes.should == 1
-      end.should output_to_fd(".")
+      suppress_warning do # https://bugs.ruby-lang.org/issues/19630
+        -> {
+          bytes = open("|cat", "w") { |io| io.write(".") }
+          bytes.should == 1
+        }.should output_to_fd(".")
+      end
     end
   end
 
   platform_is :windows do
     it "opens an io when path starts with a pipe" do
-      @io = open("|date /t")
+      suppress_warning do # https://bugs.ruby-lang.org/issues/19630
+        @io = open("|date /t")
+      end
       begin
         @io.should be_kind_of(IO)
         @io.read
@@ -63,11 +71,23 @@ describe "Kernel#open" do
     end
 
     it "opens an io when called with a block" do
-      @output = open("|date /t") { |f| f.read }
+      suppress_warning do # https://bugs.ruby-lang.org/issues/19630
+        @output = open("|date /t") { |f| f.read }
+      end
       @output.should_not == ''
     end
   end
 
+  ruby_version_is "3.3" do
+    # https://bugs.ruby-lang.org/issues/19630
+    it "warns about deprecation given a path with a pipe" do
+      cmd = "|echo ok"
+      -> {
+        open(cmd) { |f| f.read }
+      }.should complain(/Kernel#open with a leading '\|'/)
+    end
+  end
+
   it "raises an ArgumentError if not passed one argument" do
     -> { open }.should raise_error(ArgumentError)
   end