Standalone script, "... or Rails version 0.0 not supported. Failed to sync"

[wconrad]

When run with a standalone script, tunemygc fails to sync with a "version... not supported" error.

Given this program foo.rb:

ENV['RUBY_GC_SPY'] ||= 'manual'
require 'tunemygc'
require 'active_support'

TuneMyGc.booted
TuneMyGc.processing_started
TuneMyGc.processing_ended

Then running it causes the error "Ruby version 2.4.2 or Rails version 0.0 not supported. Failed to sync 10 snapshots":

$ RUBY_GC_TOKEN=(redacted) RUBY_GC_TUNE=200 bundle exec ruby foo.rb
[tunemygc] Rails not detected, loading minimal agent
I, [2017-10-28T09:55:58.529386 #10472]  INFO -- : [tunemygc, ppid: 17705, pid: 10472] interposing
I, [2017-10-28T09:55:58.532564 #10472]  INFO -- : [tunemygc, ppid: 17705, pid: 10472] hooked: GC tracepoints
I, [2017-10-28T09:55:58.533370 #10472]  INFO -- : [tunemygc, ppid: 17705, pid: 10472] hooked: manual
I, [2017-10-28T09:55:58.533391 #10472]  INFO -- : [tunemygc, ppid: 17705, pid: 10472] hooked: after_initialize
I, [2017-10-28T09:55:58.533405 #10472]  INFO -- : [tunemygc, ppid: 17705, pid: 10472] hooked: at_exit
I, [2017-10-28T09:55:58.533417 #10472]  INFO -- : [tunemygc, ppid: 17705, pid: 10472] interposed
I, [2017-10-28T09:55:58.568350 #10472]  INFO -- : [tunemygc, ppid: 17705, pid: 10472] at_exit
I, [2017-10-28T09:55:58.568387 #10472]  INFO -- : [tunemygc, ppid: 17705, pid: 10472] uninstalled manual spy
I, [2017-10-28T09:55:58.569838 #10472]  INFO -- : [tunemygc, ppid: 17705, pid: 10472] Sync required? true
I, [2017-10-28T09:55:58.569863 #10472]  INFO -- : [tunemygc, ppid: 17705, pid: 10472] Syncing 10 snapshots
I, [2017-10-28T09:55:59.192253 #10472]  INFO -- : [tunemygc, ppid: 17705, pid: 10472] Ruby version 2.4.2 or Rails version 0.0 not supported. Failed to sync 10 snapshots

These Ruby versions all gave the same error:

• ruby-2.4.2
• ruby-2.4.1
• ruby-2.4.0
• ruby-2.3.4
• ruby-2.2.5

Additional info

Gemfile:

# frozen_string_literal: true
source "https://rubygems.org"

git_source(:github) {|repo_name| "https://github.com/#{repo_name}" }

gem "activesupport"
gem "tunemygc"

Gemfile.lock:

GEM
  remote: https://rubygems.org/
  specs:
    activesupport (5.0.6)
      concurrent-ruby (~> 1.0, >= 1.0.2)
      i18n (~> 0.7)
      minitest (~> 5.1)
      tzinfo (~> 1.1)
    concurrent-ruby (1.0.5)
    i18n (0.9.0)
      concurrent-ruby (~> 1.0)
    minitest (5.10.3)
    thread_safe (0.3.6)
    tunemygc (1.0.69)
    tzinfo (1.2.3)
      thread_safe (~> 0.1)

PLATFORMS
  ruby

DEPENDENCIES
  activesupport
  tunemygc

BUNDLED WITH
   1.15.4

[wconrad]

Workaround

Requiring the rails gem makes the error go away. Here is the program with Rails required:

ENV['RUBY_GC_SPY'] ||= 'manual'
require 'tunemygc'

require 'rails'

TuneMyGc.booted
TuneMyGc.processing_started
TuneMyGc.processing_ended

and the output, which no longer has the "failed to sync" error:

wayne@treebeard:/tmp/tunemygc$ RUBY_GC_TOKEN=dc0be59c16d987aa7e24ac4e6e315985 RUBY_GC_TUNE=200 bundle exec ruby foo.rb
[tunemygc] Rails not detected, loading minimal agent
I, [2017-10-28T10:16:14.527629 #23108]  INFO -- : [tunemygc, ppid: 17621, pid: 23108] interposing
I, [2017-10-28T10:16:14.530899 #23108]  INFO -- : [tunemygc, ppid: 17621, pid: 23108] hooked: GC tracepoints
I, [2017-10-28T10:16:14.531901 #23108]  INFO -- : [tunemygc, ppid: 17621, pid: 23108] hooked: manual
I, [2017-10-28T10:16:14.531928 #23108]  INFO -- : [tunemygc, ppid: 17621, pid: 23108] hooked: after_initialize
I, [2017-10-28T10:16:14.531948 #23108]  INFO -- : [tunemygc, ppid: 17621, pid: 23108] hooked: at_exit
I, [2017-10-28T10:16:14.531962 #23108]  INFO -- : [tunemygc, ppid: 17621, pid: 23108] interposed
I, [2017-10-28T10:16:14.694887 #23108]  INFO -- : [tunemygc, ppid: 17621, pid: 23108] at_exit
I, [2017-10-28T10:16:14.694936 #23108]  INFO -- : [tunemygc, ppid: 17621, pid: 23108] uninstalled manual spy
I, [2017-10-28T10:16:14.696895 #23108]  INFO -- : [tunemygc, ppid: 17621, pid: 23108] Sync required? true
I, [2017-10-28T10:16:14.696927 #23108]  INFO -- : [tunemygc, ppid: 17621, pid: 23108] Syncing 22 snapshots
I, [2017-10-28T10:16:15.171166 #23108]  INFO -- : [tunemygc, ppid: 17621, pid: 23108] Please visit (redacted) to view your configuration and other Garbage Collector insights