$ bundle --version
Bundler version 2.1.0
$ xcversion --version
Traceback (most recent call last):
6: from /Users/autobuild/.rvm/gems/ruby-2.6.5/bin/ruby_executable_hooks:10:in `<main>'
5: from /Users/autobuild/.rvm/rubies/ruby-2.6.5/lib/ruby/gems/2.6.0/gems/executable-hooks-1.6.0/lib/executable-hooks/hooks.rb:49:in `run'
4: from /Users/autobuild/.rvm/rubies/ruby-2.6.5/lib/ruby/gems/2.6.0/gems/executable-hooks-1.6.0/lib/executable-hooks/hooks.rb:49:in `each'
3: from /Users/autobuild/.rvm/rubies/ruby-2.6.5/lib/ruby/gems/2.6.0/gems/executable-hooks-1.6.0/lib/executable-hooks/hooks.rb:50:in `block in run'
2: from /Users/autobuild/.rvm/rubies/ruby-2.6.5/lib/ruby/gems/2.6.0/gems/rubygems-bundler-1.4.5/lib/rubygems_executable_plugin.rb:4:in `block in <top (required)>'
1: from /Users/autobuild/.rvm/rubies/ruby-2.6.5/lib/ruby/site_ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
/Users/autobuild/.rvm/rubies/ruby-2.6.5/lib/ruby/site_ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require': cannot load such file -- rubygems-bundler/noexec (LoadError)
10: from /Users/autobuild/.rvm/gems/ruby-2.6.5/bin/ruby_executable_hooks:10:in `<main>'
9: from /Users/autobuild/.rvm/rubies/ruby-2.6.5/lib/ruby/gems/2.6.0/gems/executable-hooks-1.6.0/lib/executable-hooks/hooks.rb:49:in `run'
8: from /Users/autobuild/.rvm/rubies/ruby-2.6.5/lib/ruby/gems/2.6.0/gems/executable-hooks-1.6.0/lib/executable-hooks/hooks.rb:49:in `each'
7: from /Users/autobuild/.rvm/rubies/ruby-2.6.5/lib/ruby/gems/2.6.0/gems/executable-hooks-1.6.0/lib/executable-hooks/hooks.rb:50:in `block in run'
6: from /Users/autobuild/.rvm/rubies/ruby-2.6.5/lib/ruby/gems/2.6.0/gems/rubygems-bundler-1.4.5/lib/rubygems_executable_plugin.rb:4:in `block in <top (required)>'
5: from /Users/autobuild/.rvm/rubies/ruby-2.6.5/lib/ruby/site_ruby/2.6.0/rubygems/core_ext/kernel_require.rb:34:in `require'
4: from /Users/autobuild/.rvm/rubies/ruby-2.6.5/lib/ruby/site_ruby/2.6.0/rubygems/core_ext/kernel_require.rb:130:in `rescue in require'
3: from /Users/autobuild/.rvm/rubies/ruby-2.6.5/lib/ruby/site_ruby/2.6.0/rubygems/core_ext/kernel_require.rb:130:in `require'
2: from /Users/autobuild/.rvm/rubies/ruby-2.6.5/lib/ruby/gems/2.6.0/gems/rubygems-bundler-1.4.5/lib/rubygems-bundler/noexec.rb:131:in `<top (required)>'
1: from /Users/autobuild/.rvm/rubies/ruby-2.6.5/lib/ruby/gems/2.6.0/gems/rubygems-bundler-1.4.5/lib/rubygems-bundler/noexec.rb:124:in `check'
/Users/autobuild/.rvm/rubies/ruby-2.6.5/lib/ruby/gems/2.6.0/gems/rubygems-bundler-1.4.5/lib/rubygems-bundler/noexec.rb:84:in `setup': undefined method `plain_specs' for #<Bundler::RubygemsIntegration:0x00007f9ce19260a0> (NoMethodError)
With bundler 2.0.1 everything works fine.