fix for a ruby 1.9 warning message

Backported from ruby 2.0 (and possibly later 1.9 patchlevels) because it
was filling our logs with many millions of warnings. The code was
backported directly, the test was backported with conversion from
minitest -> rspec.

test plan: Delayed jobs that use ruby's net libraries should still work,
such as sending messages, taking web snapshots, etc. You shouldn't see
any further lines like this in the log:

net/protocol.rb:313: warning: regexp match /.../n against to UTF-8 string

Change-Id: Ic29daa4ee9f0587fb2a1ac2968cd08a2f68365a1
Reviewed-on: https://gerrit.instructure.com/17431
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Brian Palmer <brianp@instructure.com>
QA-Review: Brian Palmer <brianp@instructure.com>

config/initializers/ruby_version_compat.rb

@@ -144,4 +144,18 @@ else
       super.force_encoding('utf-8')
     end
   end
+
+  # Fix for https://bugs.ruby-lang.org/issues/7278 , which was filling up our logs with these warnings
+  if RUBY_VERSION < "2."
+    require 'net/protocol'
+    class Net::InternetMessageIO
+      def each_crlf_line(src)
+        buffer_filling(@wbuf, src) do
+          while line = @wbuf.slice!(/\A[^\r\n]*(?:\n|\r(?:\n|(?!\z)))/)
+            yield line.chomp("\n") + "\r\n"
+          end
+        end
+      end
+    end
+  end
 end

spec/initializers/ruby_version_compat_spec.rb

@@ -0,0 +1,23 @@
+require File.expand_path('../spec_helper', File.dirname( __FILE__ ))
+
+describe 'ruby_version_compat' do
+  describe 'backport of ruby #7278' do
+    it "should not output to stdout/stderr" do
+      pending("ruby 1.9+ only") if RUBY_VERSION < "1.9."
+
+      output = capture_io do
+        sio = StringIO.new("")
+        imio = Net::InternetMessageIO.new(sio)
+        imio.write_message("\u3042\r\u3044\n\u3046\r\n\u3048").should == 23
+        sio.string.should == "\u3042\r\n\u3044\r\n\u3046\r\n\u3048\r\n.\r\n".force_encoding('us-ascii')
+
+        sio = StringIO.new("")
+        imio = Net::InternetMessageIO.new(sio)
+        imio.write_message("\u3042\r").should == 8
+        sio.string.should == "\u3042\r\n.\r\n".force_encoding('us-ascii')
+      end
+
+      output.should == ['', '']
+    end
+  end
+end

spec/spec_helper.rb

@@ -864,6 +864,16 @@ Spec::Runner.configure do |config|
     str
   end
 
+  # from minitest, MIT licensed
+  def capture_io
+    orig_stdout, orig_stderr = $stdout, $stderr
+    $stdout, $stderr = StringIO.new, StringIO.new
+    yield
+    return $stdout.string, $stderr.string
+  ensure
+    $stdout, $stderr = orig_stdout, orig_stderr
+  end
+
   def verify_post_matches(post_lines, expected_post_lines)
     # first lines should match
     post_lines[0].should == expected_post_lines[0]