Fix Regexp.from_bson for data from SSL connections

[niels]

This PR unifies parsing of regular expressions across SSL and non-SSL connections thus fixing RUBY-1048. From the issue description:

When accessing mongodb through SSL, Regexp attributes can't be read from the database. https://github.com/mongodb/bson-ruby/blob/master/lib/bson/regexp.rb#L156 hangs indefinitely as the options are NULL_BYTE terminated.

Note that this issue only occurs when connecting through SSL. On an unencrypted connection, options are indeed "0" terminated and the bug thus doesn't manifest itself using non-encrypted connections.

The parsing of the options itself is also subject to differences between SSL and non-SSL connections.

Test case in Rails:

class TestRecord
  include Mongoid::Document
  field :regex, type: Regexp
end 

TestRecord.create(regex: //).reload # Will never return when connecting to MongoDB through SSL

[estolfo]

Hi @Nielsomat
Thanks so much for this. I've commented in the jira ticket. It'd be great if you could provide a test for the scenario your code addresses and rebase against master. Thanks!

[estolfo]

Hi @Nielsomat

Let me know if you're able to write a test for this and rebase against master so I can merge it. Thanks!

Emily

[durran]

This is also fixed on my branch:

https://github.com/mongodb/bson-ruby/pull/43/files#diff-d0d0c547552be777373e58660aabaa99R153

[niels]

@estolfo, this commit simply brings the #readbyte handling within Regexp in line with existing code such as https://github.com/mongodb/bson-ruby/blob/master/lib/bson/array.rb#L97 or https://github.com/mongodb/bson-ruby/blob/master/lib/bson/hash.rb#L77. As it is not explicitly tested there, I didn't include tests of my own. I have adapted the commit message accordingly.

It sounds like @durran's branch is the way to go in the long-term. For the short-term, I would suggest including this fix ASAP. The symptom of the bug isn't "just" invalid or incomplete data but rather the entire process hanging.

Right now, I am also working on a PR against mongodb/mongo-ruby-driver to address the underlying issue of the raw TCP and SSL socket behaving differently. I will reference this PR here once completed.

[niels]

The root cause for this is now fixed in mongodb/mongo-ruby-driver#700.

[durran]

3.2.6 also has been released with this change. :)

[niels]

😍

Excellent! Thanks, @durran!