Reproduction script for rubygems/bundler#5552

repo-5552.sh

#!/bin/bash

set -ex

mkdir /tmp/repo-5552
cd /tmp/repo-5552

bundle env
# Bundler   1.14.6
# Rubygems  2.5.1
# Ruby      2.3.1p112 (2016-04-26 revision 54768) [x86_64-darwin15]
# Git       2.10.2
# Platform  x86_64-darwin-15

cat > Gemfile << EOF
source 'https://rubygems.org'
gem 'bundler', git: '[email protected]:bundler/bundler.git'
EOF

# Expected behavior: one install will wait for the other
# Observed behavior: sporadic git index.lock error
bundle install &
bundle install &
wait