Demonstrating an issue with Bundler.with_clean_env and local path installs (#1858)

.gitignore

.bundle
Gemfile.lock
local-bundle

Gemfile

# Actual gems are not important
source :rubygems
gem 'thor'

reproduce.sh

#!/bin/bash

rm -rf .bundle 'local-bundle'
bundle install --path 'local-bundle'

echo "Shell GEM_HOME (may be blank):"
env | grep GEM_HOME

echo "bundle exec GEM_HOME:"
bundle exec env | grep GEM_HOME

echo "with_original_env GEM_HOME:"
bundle exec ruby -e 'Bundler.with_original_env { system("env") }' | grep GEM_HOME

echo "with_clean_env GEM_HOME:"
bundle exec ruby -e 'Bundler.with_clean_env { system("env") }' | grep GEM_HOME

When I run reproduce.sh with my system ruby on the path, I get this:

Fetching gem metadata from http://rubygems.org/..
Installing thor (0.14.6) 
Using bundler (1.1.3) 
Your bundle is complete! It was installed into ./local-bundle
Shell GEM_HOME (may be blank):
bundle exec GEM_HOME:
GEM_HOME=/Users/rsutphin/tmp/clean_env/local-bundle/ruby/1.8
with_original_env GEM_HOME:
GEM_HOME=/Users/rsutphin/tmp/clean_env/local-bundle/ruby/1.8
with_clean_env GEM_HOME:
GEM_HOME=/Users/rsutphin/tmp/clean_env/local-bundle/ruby/1.8

If I run it with some rvm ruby selected, I get this:

Fetching gem metadata from http://rubygems.org/..
Installing thor (0.14.6) 
Using bundler (1.1.3) 
Your bundle is complete! It was installed into ./local-bundle
Shell GEM_HOME (may be blank):
GEM_HOME=/Users/rsutphin/.rvm/gems/ruby-1.9.3-p125
bundle exec GEM_HOME:
GEM_HOME=/Users/rsutphin/tmp/clean_env/local-bundle/ruby/1.9.1
with_original_env GEM_HOME:
GEM_HOME=/Users/rsutphin/tmp/clean_env/local-bundle/ruby/1.9.1
with_clean_env GEM_HOME:
GEM_HOME=/Users/rsutphin/tmp/clean_env/local-bundle/ruby/1.9.1

In both cases, the "original" and "clean" envs are tainted with the GEM_HOME set by bundler.