Autopkgtest regression trigerred by Ruby 2.7

[Lucas Kanashiro]

ruby-em-hiredis version 0.3.1-1 has a regression in all architectures triggered by ruby-defaults/1:2.7~0.

autopkgtest log on amd64 as an example:

https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac/autopkgtest-focal/focal/amd64/r/ruby-em-hiredis/20200305_182652_94b8d@/log.gz

[Rafael David Tinoco (rafaeldtinoco)]

"lib/em-hiredis/client.rb":

    def eval_script(lua, lua_sha, keys, args)
      df = EM::DefaultDeferrable.new
      method_missing(:evalsha, lua_sha, keys.size, *keys, *args).callback(
        &df.method(:succeed)
      ).errback { |e|
        if e.kind_of?(RedisError) && e.redis_error.message.start_with?("NOSCRIPT")
          self.eval(lua, keys.size, *keys, *args)
            .callback(&df.method(:succeed)).errback(&df.method(:fail))
        else
          df.fail(e)
        end
      }
      df
    end

whenever evalsha method is not available, self.eval(lua, keys.size, *keys, *args) complains about the number of variables being given to self.eval(). It is likely that the method definition (self) has changed among ruby versions. The arguments seem fine, example:

lua =

-- Set key to token with expiry of timeout, if:
-- - It doesn't exist
-- - It exists and already has value of token (further set extends timeout)
-- Used to implement a re-entrant lock.
local key = KEYS[1]
local token = ARGV[1]
local timeout = ARGV[2]

local value = redis.call('get', key)

if value == token or not value then
    -- Great, either we hold the lock or it's free for us to take
    return redis.call('setex', key, timeout, token)
else
    -- Someone else has it
    return false
end

lua_sha = 32d8d2000576c02c167c899979858c886d4524aa
keys = ["test-lock"]
args= ["b978de50e36126d49314bbcec2ccc76e", 2]

[Lucas Kanashiro (lucaskanashiro)]

Upstream is dead and only ruby-em-synchrony depends on it, so I decided to make ruby-em-synchrony not depend on it anymore and request its removal from Focal:

https://bugs.launchpad.net/ubuntu/+source/ruby-em-hiredis/+bug/1869434

The same was made in Debian.

[Lucas Kanashiro (lucaskanashiro)]

ruby-em-hiredis was already removed from Focal, check the bug url linked above.