Multithread error

[myxaluch]

Hello!

We use your gems in high-load application and faced with a problem :
NoMethodError in function .find_by_unicode/.find_by_alias.After some review, we found problem: when we use Gemoji in multithreading, variable @all defined in first thread, but not fill-in yet. Second thread use .find_by_unicode, pass check on @all and return not defined @unicode_index => NoMethodError.

I create a RSpec test for you:(it don't looks great, but I have small xp in testing yet:) )

require 'emoji'

RSpec.describe "Multithread error" do

  it "raises" do
    Thread.new { 10000.times { Emoji.find_by_unicode 't' }}
    expect { Emoji.find_by_unicode 't' }.to raise_error {NoMethodError}
  end
end

and propose to use Mutex in this functions to avoid this problem.

private
@mutex = Mutex.new
...

def find_by_unicode(unicode)
   @mutex.syncronize do
      unicodes_index[unicode]
  end
end

def find_by_alias(unicode)
   @mutex.syncronize do
      names_index[names]
  end
end

Maybe, you have another ideas for this error :)

[mislav]

Thanks for reporting! Would you submit a pull request that adds a mutex around building the index?

[myxaluch]

@mislav Of course, but we fix this problem in version 2.1.0. In 3.0.0rc1, you use find_by_unicode inside parse_data_file, and this fix crash all :(. I will think about more useful fix for new version