Auto merge of #5804 - bundler:seg-remove-postit-trampoline, r=indirect

Completely remove the postit trampoline

### What was the end-user problem that led to this PR?

The problem was the bundler trampoline we tried to introduce never completely worked, it worked even less with bundler installed as a default gem (as we intend to do with RubyGems, like, a year ago), and it worked by doing disgusting things that we couldn't be confident would work under all circumstances.

### Was was your diagnosis of the problem?

My diagnosis was our best bet was to completely remove the trampoline from bundler itself.
We intend to address the user story of switching bundler versions in RubyGems directly, where the gymnastics required will hopefully be much less obtrusive. Additionally

### What is your fix for the problem, implemented in this PR?

My fix is to completely delete all references to trampolining / postit from Bundler and admit defeat.

### Why did you choose this fix out of the possible options?

I chose this fix because I'm unwilling to maintain the trampoline any longer, and since it's never been enabled, I feel this is my last chance to pull it from Bundler before I'm stuck maintaining code that doesn't work for all eternity. This will also _finally_ unblock me shipping RubyGems 2.7.

(cherry picked from commit bd95735df25ceac9de8f2186be37079f6cf3d385)

# Conflicts:
#	doc/development/SETUP.md
#	lib/bundler/postit_trampoline.rb
#	spec/other/trampoline_spec.rb

17 files changed, 5 insertions, 470 deletions

diff --git a/Rakefile b/Rakefile
index 9b45136402..e8813c38e3 100644
--- a/Rakefile
+++ b/Rakefile
@@ -299,13 +299,6 @@ begin
     lib.vendor_lib = "lib/bundler/vendor/thor"
   end
 
-  Automatiek::RakeTask.new("postit") do |lib|
-    lib.download = { :github => "https://github.com/bundler/postit" }
-    lib.namespace = "PostIt"
-    lib.prefix = "BundlerVendoredPostIt"
-    lib.vendor_lib = "lib/bundler/vendor/postit"
-  end
-
   Automatiek::RakeTask.new("net-http-persistent") do |lib|
     lib.download = { :github => "https://github.com/drbrain/net-http-persistent" }
     lib.namespace = "Net::HTTP::Persistent"
@@ -326,7 +319,6 @@ rescue LoadError
   namespace :vendor do
     task(:molinillo) { abort "Install the automatiek gem to be able to vendor gems." }
     task(:thor) { abort "Install the automatiek gem to be able to vendor gems." }
-    task(:postit) { abort "Install the automatiek gem to be able to vendor gems." }
     task("net-http-persistent") { abort "Install the automatiek gem to be able to vendor gems." }
   end
 end
diff --git a/doc/development/SETUP.md b/doc/development/SETUP.md
index 10f8dd30f1..ea6a9d5c0b 100644
--- a/doc/development/SETUP.md
+++ b/doc/development/SETUP.md
@@ -20,9 +20,7 @@ Bundler doesn't use a Gemfile to list development dependencies, because when we
 
 4. Set up a shell alias to run Bundler from your clone, e.g. a Bash alias:
 
-      $ alias dbundle='BUNDLE_TRAMPOLINE_DISABLE=1 ruby -I /path/to/bundler/lib /path/to/bundler/exe/bundle'
-
-   The `BUNDLE_TRAMPOLINE_DISABLE` environment variable ensures that the version of Bundler in `/path/to/bundler/lib` will be used. Without that environment setting, Bundler will automatically download, install, and run the version of Bundler listed in `Gemfile.lock`. With that set up, you can test changes you've made to Bundler by running `dbundle`, without interfering with the regular `bundle` command.
+      `$ alias dbundle='ruby -I /path/to/bundler/lib /path/to/bundler/exe/bundle'`
 
 ## Debugging with `pry`
 
diff --git a/exe/bundle b/exe/bundle
index ab2bde16e2..cf03a523ab 100755
--- a/exe/bundle
+++ b/exe/bundle
@@ -7,11 +7,6 @@ Signal.trap("INT") do
   exit 1
 end
 
-update = "update".start_with?(ARGV.first || " ") && ARGV.find {|a| a.start_with?("--bundler") }
-update &&= update =~ /--bundler(?:=(.+))?/ && $1 || "> 0.a"
-ENV["BUNDLER_VERSION"] = update if update
-require "bundler/postit_trampoline"
-
 require "bundler"
 # Check if an older version of bundler is installed
 $LOAD_PATH.each do |path|
diff --git a/lib/bundler/cli.rb b/lib/bundler/cli.rb
index 7110949fda..5b5d4e4f78 100644
--- a/lib/bundler/cli.rb
+++ b/lib/bundler/cli.rb
@@ -612,7 +612,7 @@ module Bundler
     end
 
     def print_command
-      return unless ENV["BUNDLE_POSTIT_TRAMPOLINING_VERSION"] || Bundler.ui.debug?
+      return unless Bundler.ui.debug?
       _, _, config = @_initializer
       current_command = config[:current_command]
       command_name = current_command.name
diff --git a/lib/bundler/cli/install.rb b/lib/bundler/cli/install.rb
index 7be842d46f..ff6bedd9fd 100644
--- a/lib/bundler/cli/install.rb
+++ b/lib/bundler/cli/install.rb
@@ -13,8 +13,6 @@ module Bundler
 
       warn_if_root
 
-      warn_if_outdated
-
       [:with, :without].each do |option|
         if options[option]
           options[option] = options[option].join(":").tr(" ", ":").split(":")
@@ -116,20 +114,6 @@ module Bundler
         "application for all non-root users on this machine.", :wrap => true
     end
 
-    def warn_if_outdated
-      return if ENV["BUNDLE_POSTIT_TRAMPOLINING_VERSION"].nil?
-      installed_version = Gem::Version.new(ENV["BUNDLE_POSTIT_TRAMPOLINING_VERSION"].dup)
-      running_version = Gem::Version.new(Bundler::VERSION)
-      return if Gem::Requirement.new(installed_version).satisfied_by?(running_version)
-      if Bundler.settings[:warned_version].nil? || running_version > Gem::Version.new(Bundler.settings[:warned_version])
-        Bundler.settings[:warned_version] = running_version
-        Bundler.ui.warn "You're running Bundler #{installed_version} but this " \
-          "project uses #{running_version}. To update, run `bundle update " \
-          "--bundler`. You won't see this message again unless you upgrade " \
-          "to a newer version of Bundler.", :wrap => true
-      end
-    end
-
     def dependencies_count_for(definition)
       count = definition.dependencies.count
       "#{count} Gemfile #{count == 1 ? "dependency" : "dependencies"}"
diff --git a/lib/bundler/postit_trampoline.rb b/lib/bundler/postit_trampoline.rb
deleted file mode 100644
index b62a5e7676..0000000000
--- a/lib/bundler/postit_trampoline.rb
+++ /dev/null
@@ -1,73 +0,0 @@
-# frozen_string_literal: true
-
-module BundlerVendoredPostIt; end
-require "bundler/vendor/postit/lib/postit"
-require "rubygems"
-
-environment = BundlerVendoredPostIt::PostIt::Environment.new([])
-version = Gem::Requirement.new(environment.bundler_version)
-if version.requirements.size == 1 && version.requirements.first.first == "=" # version.exact?
-  if version.requirements.first.last.segments.first >= 2
-    ENV["BUNDLE_TRAMPOLINE_FORCE"] = "true"
-  end
-end
-
-if ENV["BUNDLE_TRAMPOLINE_FORCE"] && !ENV["BUNDLE_TRAMPOLINE_DISABLE"]
-  installed_version =
-    if defined?(Bundler::VERSION)
-      Bundler::VERSION
-    else
-      File.read(File.expand_path("../version.rb", __FILE__)) =~ /VERSION = "(.+)"/
-      $1
-    end
-  installed_version &&= Gem::Version.new(installed_version)
-
-  if !version.satisfied_by?(installed_version)
-    begin
-      installer = BundlerVendoredPostIt::PostIt::Installer.new(version)
-      unless installer.installed?
-        warn "Installing locked Bundler version #{version.to_s.gsub("= ", "")}..."
-        installer.install!
-      end
-    rescue => e
-      abort <<-EOS.strip
-Installing the inferred bundler version (#{version}) failed.
-If you'd like to update to the current bundler version (#{installed_version}) in this project, run `bundle update --bundler`.
-The error was: #{e}
-    EOS
-    end
-
-    if deleted_spec = Gem.loaded_specs.delete("bundler")
-      deleted_spec.full_require_paths.each {|path| $:.delete(path) }
-    else
-      $:.delete(File.expand_path("../..", __FILE__))
-    end
-    gem "bundler", version
-  else
-    begin
-      gem "bundler", version
-    rescue LoadError
-      $:.unshift(File.expand_path("../..", __FILE__))
-    end
-  end
-
-  running_version = begin
-    require "bundler/version"
-    Bundler::VERSION
-  rescue LoadError, NameError
-    nil
-  end
-
-  ENV["BUNDLE_POSTIT_TRAMPOLINING_VERSION"] = installed_version.to_s
-
-  if !Gem::Requirement.new(">= 1.13.pre".dup).satisfied_by?(Gem::Version.new(running_version)) && (ARGV.empty? || ARGV.any? {|a| %w(install i).include? a })
-    puts <<-WARN.strip
-You're running Bundler #{installed_version} but this project uses #{running_version}. To update, run `bundle update --bundler`.
-  WARN
-  end
-
-  if !Gem::Version.correct?(running_version.to_s) || !version.satisfied_by?(Gem::Version.create(running_version))
-    abort "The running bundler (#{running_version}) does not match the required `#{version}`"
-  end
-
-end # if ENV["BUNDLE_TRAMPOLINE_FORCE"] && !ENV["BUNDLE_TRAMPOLINE_DISABLE"]
diff --git a/lib/bundler/setup.rb b/lib/bundler/setup.rb
index eb816b9988..9aae6478cd 100644
--- a/lib/bundler/setup.rb
+++ b/lib/bundler/setup.rb
@@ -1,5 +1,4 @@
 # frozen_string_literal: true
-require "bundler/postit_trampoline"
 require "bundler/shared_helpers"
 
 if Bundler::SharedHelpers.in_bundle?
@@ -20,12 +19,9 @@ if Bundler::SharedHelpers.in_bundle?
     Bundler.setup
   end
 
-  unless ENV["BUNDLE_POSTIT_TRAMPOLINING_VERSION"]
-    # Add bundler to the load path after disabling system gems
-    # This is guaranteed to be done already if we've trampolined
-    bundler_lib = File.expand_path("../..", __FILE__)
-    $LOAD_PATH.unshift(bundler_lib) unless $LOAD_PATH.include?(bundler_lib)
-  end
+  # Add bundler to the load path after disabling system gems
+  bundler_lib = File.expand_path("../..", __FILE__)
+  $LOAD_PATH.unshift(bundler_lib) unless $LOAD_PATH.include?(bundler_lib)
 
   Bundler.ui = nil
 end
diff --git a/lib/bundler/vendor/postit/lib/postit.rb b/lib/bundler/vendor/postit/lib/postit.rb
deleted file mode 100644
index e07dfccac4..0000000000
--- a/lib/bundler/vendor/postit/lib/postit.rb
+++ /dev/null
@@ -1,15 +0,0 @@
-require 'bundler/vendor/postit/lib/postit/environment'
-require 'bundler/vendor/postit/lib/postit/installer'
-require 'bundler/vendor/postit/lib/postit/parser'
-require 'bundler/vendor/postit/lib/postit/version'
-require 'rubygems'
-
-module BundlerVendoredPostIt::PostIt
-  def self.setup
-    load File.expand_path('../postit/setup.rb', __FILE__)
-  end
-
-  def self.bundler_version
-    defined?(Bundler::VERSION) && Bundler::VERSION
-  end
-end
diff --git a/lib/bundler/vendor/postit/lib/postit/environment.rb b/lib/bundler/vendor/postit/lib/postit/environment.rb
deleted file mode 100644
index 0c27f2cd69..0000000000
--- a/lib/bundler/vendor/postit/lib/postit/environment.rb
+++ /dev/null
@@ -1,44 +0,0 @@
-require 'bundler/vendor/postit/lib/postit/parser'
-
-module BundlerVendoredPostIt::PostIt
-  class Environment
-    def initialize(argv)
-      @argv = argv
-    end
-
-    def env_var_version
-      ENV['BUNDLER_VERSION']
-    end
-
-    def cli_arg_version
-      return unless str = @argv.first
-      str = str.dup.force_encoding('BINARY') if str.respond_to?(:force_encoding)
-      if Gem::Version.correct?(str)
-        @argv.shift
-        str
-      end
-    end
-
-    def gemfile
-      ENV['BUNDLE_GEMFILE'] || 'Gemfile'
-    end
-
-    def lockfile
-      File.expand_path case File.basename(gemfile)
-                       when 'gems.rb' then gemfile.sub(/\.rb$/, gemfile)
-                       else "#{gemfile}.lock"
-                       end
-    end
-
-    def lockfile_version
-      BundlerVendoredPostIt::PostIt::Parser.new(lockfile).parse
-    end
-
-    def bundler_version
-      @bundler_version ||= begin
-        env_var_version || cli_arg_version ||
-          lockfile_version || "#{Gem::Requirement.default}.a"
-      end
-    end
-  end
-end
diff --git a/lib/bundler/vendor/postit/lib/postit/installer.rb b/lib/bundler/vendor/postit/lib/postit/installer.rb
deleted file mode 100644
index 5fa34b6938..0000000000
--- a/lib/bundler/vendor/postit/lib/postit/installer.rb
+++ /dev/null
@@ -1,28 +0,0 @@
-module BundlerVendoredPostIt::PostIt
-  class Installer
-    def initialize(bundler_version)
-      @bundler_version = bundler_version
-    end
-
-    def installed?
-      if Gem::Specification.respond_to?(:find_by_name)
-        !Gem::Specification.find_by_name('bundler', @bundler_version).nil?
-      else
-        requirement = Gem::Requirement.new(@bundler_version)
-        Gem.source_index.gems.values.any? do |s|
-          s.name == 'bundler' && requirement.satisfied_by?(s.version)
-        end
-      end
-    rescue LoadError
-      false
-    end
-
-    def install!
-      return if installed?
-      require 'rubygems/dependency_installer'
-      installer = Gem::DependencyInstaller.new
-      installer.install('bundler', @bundler_version)
-      installer.installed_gems
-    end
-  end
-end
diff --git a/lib/bundler/vendor/postit/lib/postit/parser.rb b/lib/bundler/vendor/postit/lib/postit/parser.rb
deleted file mode 100644
index 7b2eb72ff1..0000000000
--- a/lib/bundler/vendor/postit/lib/postit/parser.rb
+++ /dev/null
@@ -1,21 +0,0 @@
-require 'rubygems'
-
-module BundlerVendoredPostIt::PostIt
-  class Parser
-    def initialize(file)
-      @file = file
-    end
-
-    BUNDLED_WITH =
-      /\n\nBUNDLED WITH\n\s{2,}(#{Gem::Version::VERSION_PATTERN})\n/
-
-    def parse
-      return unless lockfile = File.file?(@file) && File.read(@file)
-      if lockfile =~ BUNDLED_WITH
-        Regexp.last_match(1)
-      else
-        '< 1.10'
-      end
-    end
-  end
-end
diff --git a/lib/bundler/vendor/postit/lib/postit/setup.rb b/lib/bundler/vendor/postit/lib/postit/setup.rb
deleted file mode 100644
index 2580e7b7b8..0000000000
--- a/lib/bundler/vendor/postit/lib/postit/setup.rb
+++ /dev/null
@@ -1,12 +0,0 @@
-require 'bundler/vendor/postit/lib/postit/environment'
-require 'bundler/vendor/postit/lib/postit/installer'
-
-environment = BundlerVendoredPostIt::PostIt::Environment.new(ARGV)
-version = environment.bundler_version
-
-installer = BundlerVendoredPostIt::PostIt::Installer.new(version)
-installer.install!
-
-gem 'bundler', version
-
-require 'bundler/version'
diff --git a/lib/bundler/vendor/postit/lib/postit/version.rb b/lib/bundler/vendor/postit/lib/postit/version.rb
deleted file mode 100644
index b54175254d..0000000000
--- a/lib/bundler/vendor/postit/lib/postit/version.rb
+++ /dev/null
@@ -1,3 +0,0 @@
-module BundlerVendoredPostIt::PostIt
-  VERSION = '0.2.0'.freeze
-end
diff --git a/man/bundle.ronn b/man/bundle.ronn
index 9e42e046a7..c0726c9dcd 100644
--- a/man/bundle.ronn
+++ b/man/bundle.ronn
@@ -97,24 +97,6 @@ When running a command that isn't listed in PRIMARY COMMANDS or UTILITIES,
 Bundler will try to find an executable on your path named `bundler-<command>`
 and execute it, passing down any extra arguments to it.
 
-## BUNDLER TRAMPOLINING
-
-Bundler includes a feature called trampolining, designed to allow a single
-developer to work on multiple projects, each on different Bundler versions.
-The trampoline will infer the correct version of Bundler to use for each project
-and load that version instead of the version directly invoked (which is almost
-always the newest version installed locally).
-
-Bundler by default will use the Bundler version in the current directory to
-determine the version to trampoline to, reading from the `BUNDLED WITH` section.
-However, if the `BUNDLER_VERSION` environment variable is set, that version will
-override the lockfile inference and can be used in directories without a
-lockfile.
-
-Until the target version is Bundler 2 or later, `BUNDLE_TRAMPOLINE_FORCE` must
-be set for the trampoline to be used. Additionally, `BUNDLE_TRAMPOLINE_DISABLE` can
-be set to completely disable the trampoline.
-
 ## OBSOLETE
 
 These commands are obsolete and should no longer be used
diff --git a/spec/commands/install_spec.rb b/spec/commands/install_spec.rb
index 49eee01910..0c149d93b9 100644
--- a/spec/commands/install_spec.rb
+++ b/spec/commands/install_spec.rb
@@ -485,25 +485,4 @@ RSpec.describe "bundle install with gem sources" do
                         "setting them for authentication.")
     end
   end
-
-  describe "warns user if Bundler is outdated" do
-    it "warns only once and is > 1.13.0.rc.1" do
-      gemfile <<-G
-        source "file://#{gem_repo1}"
-      G
-
-      bundle :install, :env => { "BUNDLE_POSTIT_TRAMPOLINING_VERSION" => "999" }
-      expect(out).to include("You're running Bundler 999 but this project uses #{Bundler::VERSION}.")
-
-      bundle :install, :env => { "BUNDLE_POSTIT_TRAMPOLINING_VERSION" => "999" }
-      expect(out).not_to include("You're running Bundler 999 but this project uses #{Bundler::VERSION}.")
-    end
-
-    it "should not print warning if versions match" do
-      bundle :init
-      bundle :install, :env => { "BUNDLE_POSTIT_TRAMPOLINING_VERSION" => Bundler::VERSION }
-      expect(out).to start_with("Running `bundle install --no-color` with bundler #{Bundler::VERSION}\nThe Gemfile specifies no dependencies")
-      expect(out).not_to include("You're running Bundler #{Bundler::VERSION} but this project uses #{Bundler::VERSION}.")
-    end
-  end
 end
diff --git a/spec/other/trampoline_spec.rb b/spec/other/trampoline_spec.rb
deleted file mode 100644
index 39de7048c7..0000000000
--- a/spec/other/trampoline_spec.rb
+++ /dev/null
@@ -1,194 +0,0 @@
-# frozen_string_literal: true
-require "spec_helper"
-
-RSpec.describe "bundler version trampolining" do
-  before do
-    ENV["BUNDLE_TRAMPOLINE_DISABLE"] = nil
-    ENV["BUNDLE_TRAMPOLINE_FORCE"] = "true"
-    FileUtils.rm_rf(system_gem_path)
-    FileUtils.cp_r(base_system_gems, system_gem_path)
-  end
-
-  context "version guessing" do
-    shared_examples_for "guesses" do |version|
-      it "guesses the correct bundler version" do
-        bundle! "--version"
-        expect(out).to eq("Bundler version #{version}")
-
-        if bundled_app("Gemfile").file?
-          bundle! "exec ruby -e 'puts Bundler::VERSION'"
-          expect(out).to eq(version)
-        end
-      end
-    end
-
-    context "with a lockfile" do
-      before do
-        install_gemfile ""
-        lockfile lockfile.sub(Bundler::VERSION, "1.12.0")
-      end
-
-      include_examples "guesses", "1.12.0"
-    end
-
-    context "with BUNDLER_VERSION" do
-      before do
-        ENV["BUNDLER_VERSION"] = "1.12.0"
-      end
-
-      context "with a lockfile" do
-        before { install_gemfile "" }
-        include_examples "guesses", "1.12.0"
-      end
-
-      context "without a lockfile" do
-        include_examples "guesses", "1.12.0"
-      end
-    end
-
-    context "with no hints" do
-      include_examples "guesses", Bundler::VERSION
-    end
-
-    context "with a gemfile and no lockfile" do
-      before do
-        gemfile ""
-      end
-
-      include_examples "guesses", Bundler::VERSION
-    end
-  end
-
-  context "without BUNDLE_TRAMPOLINE_FORCE" do
-    before { ENV["BUNDLE_TRAMPOLINE_FORCE"] = nil }
-
-    context "when the version is >= 2" do
-      let(:version) { "2.7182818285" }
-      before do
-        simulate_bundler_version version do
-          install_gemfile! ""
-        end
-      end
-
-      it "trampolines automatically", :realworld => true do
-        bundle "--version"
-        expect(err).to include("Installing locked Bundler version #{version}...")
-      end
-    end
-  end
-
-  context "installing missing bundler versions", :realworld => true do
-    before do
-      ENV["BUNDLER_VERSION"] = "1.12.3"
-      if Bundler::RubygemsIntegration.provides?("< 2.6.4")
-        # necessary since we intall with 2.6.4 but the specs can run against
-        # older versions that match againt the "gem" invocation
-        %w(bundle bundler).each do |exe|
-          system_gem_path.join("bin", exe).open("a") do |f|
-            f << %(\ngem "bundler", ">= 0.a"\n)
-          end
-        end
-      end
-    end
-
-    it "guesses & installs the correct bundler version" do
-      expect(system_gem_path.join("gems", "bundler-1.12.3")).not_to exist
-      bundle! "--version"
-      expect(out).to eq("Bundler version 1.12.3")
-      expect(system_gem_path.join("gems", "bundler-1.12.3")).to exist
-    end
-
-    it "fails gracefully when installing the bundler fails" do
-      ENV["BUNDLER_VERSION"] = "9999"
-      bundle "--version"
-      expect(err).to start_with(<<-E.strip)
-Installing locked Bundler version 9999...
-Installing the inferred bundler version (= 9999) failed.
-If you'd like to update to the current bundler version (#{Bundler::VERSION}) in this project, run `bundle update --bundler`.
-The error was:
-      E
-    end
-
-    it "displays installing message before install is started" do
-      expect(system_gem_path.join("gems", "bundler-1.12.3")).not_to exist
-      bundle! "--version"
-      expect(err).to include("Installing locked Bundler version #{ENV["BUNDLER_VERSION"]}...")
-    end
-
-    it "doesn't display installing message if locked version is installed" do
-      expect(system_gem_path.join("gems", "bundler-1.12.3")).not_to exist
-      bundle! "--version"
-      expect(system_gem_path.join("gems", "bundler-1.12.3")).to exist
-      bundle! "--version"
-      expect(err).not_to include("Installing locked Bundler version = #{ENV["BUNDLER_VERSION"]}...")
-    end
-  end
-
-  context "bundle update --bundler" do
-    before do
-      simulate_bundler_version("1.11.1") do
-        install_gemfile ""
-      end
-    end
-
-    it "updates to the specified version" do
-      # HACK: since no released bundler version actually supports this feature!
-      bundle "update --bundler=1.12.0"
-      expect(out).to include("Unknown switches '--bundler=1.12.0'")
-    end
-
-    it "updates to the specified (running) version" do
-      # HACK: since no released bundler version actually supports this feature!
-      bundle! "update --bundler=#{Bundler::VERSION}"
-      bundle! "--version"
-      expect(out).to eq("Bundler version #{Bundler::VERSION}")
-    end
-
-    it "updates to the running version" do
-      # HACK: since no released bundler version actually supports this feature!
-      bundle! "update --bundler"
-      bundle! "--version"
-      expect(out).to eq("Bundler version #{Bundler::VERSION}")
-    end
-  end
-
-  context "-rbundler/setup" do
-    before do
-      simulate_bundler_version("1.12.0") do
-        install_gemfile ""
-      end
-    end
-
-    it "uses the locked version" do
-      ruby! <<-R
-        require "bundler/setup"
-        puts Bundler::VERSION
-      R
-      expect(err).to be_empty
-      expect(out).to include("1.12.0")
-    end
-  end
-
-  context "warnings" do
-    before do
-      simulate_bundler_version("1.12.0") do
-        install_gemfile ""
-      end
-    end
-
-    it "warns user if Bundler is outdated and is < 1.13.0.rc.1" do
-      ENV["BUNDLER_VERSION"] = "1.12.0"
-      bundle! "install"
-      expect(out).to include(<<-WARN.strip)
-You're running Bundler #{Bundler::VERSION} but this project uses #{ENV["BUNDLER_VERSION"]}. To update, run `bundle update --bundler`.
-      WARN
-    end
-  end
-
-  context "with --verbose" do
-    it "prints the running command" do
-      bundle! "config", :verbose => true, :env => { "BUNDLE_POSTIT_TRAMPOLINING_VERSION" => Bundler::VERSION }
-      expect(out).to start_with("Running `bundle config --verbose` with bundler #{Bundler::VERSION}")
-    end
-  end
-end
diff --git a/spec/support/helpers.rb b/spec/support/helpers.rb
index a1b74d2726..d971ea92c3 100644
--- a/spec/support/helpers.rb
+++ b/spec/support/helpers.rb
@@ -12,7 +12,6 @@ module Spec
       end
       FileUtils.mkdir_p(home)
       FileUtils.mkdir_p(tmpdir)
-      ENV["BUNDLE_TRAMPOLINE_DISABLE"] = "1"
       Bundler.reset!
       Bundler.ui = nil
       Bundler.ui # force it to initialize