Solargraph fails to start with NoMethodError when Gem::Specification is extended

[AngusGMorrison]

I'm trying to use Solargraph for a Rails project in which a method that has been added to Gem::Specification with class_eval is called in a gemspec file. Solargraph fails to start with a NoMethodError for the added method.

I've tried using the require field in solargraph.yaml to ensure that the file containing the Gem::Specification extension is loaded, to no effect. Any pointers you can provide would be much appreciated.

Stack trace:

❯ solargraph scan
Traceback (most recent call last):
	23: from /Users/angus/.rbenv/versions/2.6.6/bin/solargraph:23:in `<main>'
	22: from /Users/angus/.rbenv/versions/2.6.6/bin/solargraph:23:in `load'
	21: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/solargraph-0.39.17/bin/solargraph:5:in `<top (required)>'
	20: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/thor-1.0.1/lib/thor/base.rb:485:in `start'
	19: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/thor-1.0.1/lib/thor.rb:392:in `dispatch'
	18: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/thor-1.0.1/lib/thor/invocation.rb:127:in `invoke_command'
	17: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/thor-1.0.1/lib/thor/command.rb:27:in `run'
	16: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/solargraph-0.39.17/lib/solargraph/shell.rb:172:in `scan'
	15: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/benchmark-0.1.0/lib/benchmark.rb:293:in `measure'
	14: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/solargraph-0.39.17/lib/solargraph/shell.rb:173:in `block in scan'
	13: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/solargraph-0.39.17/lib/solargraph/api_map.rb:169:in `load'
	12: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/solargraph-0.39.17/lib/solargraph/api_map.rb:169:in `new'
	11: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/solargraph-0.39.17/lib/solargraph/workspace.rb:29:in `initialize'
	10: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/solargraph-0.39.17/lib/solargraph/workspace.rb:165:in `generate_require_paths'
	 9: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/solargraph-0.39.17/lib/solargraph/workspace.rb:165:in `each'
	 8: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/solargraph-0.39.17/lib/solargraph/workspace.rb:170:in `block in generate_require_paths'
	 7: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/solargraph-0.39.17/lib/solargraph/workspace.rb:170:in `chdir'
	 6: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/solargraph-0.39.17/lib/solargraph/workspace.rb:173:in `block (2 levels) in generate_require_paths'
	 5: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/solargraph-0.39.17/lib/solargraph/workspace.rb:173:in `eval'
	 4: from /Users/angus/code/gh/bambooengineering/umbrella/banco-broker-gateway/banco-broker-gateway.gemspec:8:in `<main>'
	 3: from /Users/angus/code/gh/bambooengineering/umbrella/banco-broker-gateway/banco-broker-gateway.gemspec:8:in `new'
	 2: from /Users/angus/.rbenv/versions/2.6.6/lib/ruby/2.6.0/rubygems/specification.rb:2067:in `initialize'
	 1: from /Users/angus/code/gh/bambooengineering/umbrella/banco-broker-gateway/banco-broker-gateway.gemspec:18:in `block in <main>'
/Users/angus/.rbenv/versions/2.6.6/lib/ruby/2.6.0/rubygems/specification.rb:2176:in `method_missing': undefined method `global_version_add_dependency' for #<Gem::Specification:0x00007fa06a8d6168> (NoMethodError)

The offending lines in banco-broker-gateway/banco-broker-gateway.gemspec:

Gem::Specification.new do |s|
  # ...
  s.global_version_add_dependency "rails"
  s.global_version_add_dependency "rest-client"
end

The definition of global_version_add_dependency in banco-shared/lib/gem_helper.rb:

Gem::Specification.class_eval do
  def global_version_add_dependency(gem_name)
    add_dependency gem_name, Banco::Versions.global_gem_version(gem_name)
  end
end