[CHEF-2947] properly remove STDERR from list of fds to select/read

Properly remove child's stderr pipe from the list of IO objects to
select on in the case that stdout has already been removed from the
list. This prevents a situation where the stdout stream is always
considered readable by select (because it has reached eof) but ShellOut
would attempt to read from it in a tight loop. Since GC is disabled
while a command is running, this would generate a bunch of EOFError
objects that were not reaped and use a ton of heap space.

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/mixlib/shellout/unix.rb b/lib/mixlib/shellout/unix.rb
index 243ca24..fe307b5 100644
--- a/lib/mixlib/shellout/unix.rb
+++ b/lib/mixlib/shellout/unix.rb
@@ -185,7 +185,7 @@ module Mixlib
         end
       rescue Errno::EAGAIN
       rescue EOFError
-        open_pipes.delete_at(0)
+        open_pipes.delete(child_stdout)
       end
 
       def read_stderr_to_buffer
@@ -194,7 +194,7 @@ module Mixlib
         end
       rescue Errno::EAGAIN
       rescue EOFError
-        open_pipes.delete_at(1)
+        open_pipes.delete(child_stderr)
       end
 
       def fork_subprocess