Is Ruby's Net::HTTP threadsafe?

Question

Is Ruby's Net::HTTP threadsafe?

(Aside from the version_1_1 and version_1_2 methods which it explicitly says aren't)

Answer 1

I wouldn't count on it.

In 2008, matz wrote:

For MRI (1.8.x) and YARV (1.9.x), every C implemented methods are protected by GIL (Global Interpreter Lock), so that you don't have to worry about. But it might depend on each implementation.

Net::HTTP is in stdlib, which means it is not implemented in C (or at least, not fully implemented in C). I am assuming that matz's note on the GIL is still correct today, which would imply that the GIL would not be placed on Net::HTTP. Therefore, I doubt it would be threadsafe.

I have unfortunately not found definitive evidence in the docs for the current version of Ruby, though I feel it is also worth mentioning this bit from Concurrency in jruby:

At least these classes [core classes and classes in the stdlib] are not considered thread-safe, and if you intend to mutate them concurrently with other operations you will want to introduce locking (e.g. with Mutex): String, Array, Hash, and any data structures derived from them.

I feel it would be best to play it safe by either adding locks around Net::HTTP or using a threadsafe alternative.