Breaking change: Remove dependencies on external gems

v0.9.3 introduced two new features that required reliance on external
libraries. Installing these libraries through our Traveling
Ruby-packaged executable has introduced issues for users. Some users
reported permissions issues related to now-deprecated Bundler behavior
that is still in use on the version of Bundler used by Traveling Ruby
(Ruby 2.2.2 is still locked to Bundler 1.9.x).

After spending considerable time attempting to work through packaging
problems I now think that the potential benefits from these dependencies
are not worth the trouble. We can accomplish most of the needed
functionality without help from external gems.

This commit makes the following changes to Parity:

- **BREAKING CHANGE** Remove the `dotenv` gem and stop loading `ERB`. We
  were previously using `dotenv` and `erb` to allow users to define
  their database name in development dynamically in a `database.yml.erb`
  file that included environment variables. This configuration is an
  edge case that doesn't warrant adding non-trivial complexity to
  accommodate.
- Remove the `git` gem. This gem parsed Git remotes, allowing parity to
  determine the application name and pass the confirmation argument for
  applications named differently than the local development directory.
  This functionality has been retained by leveraging Heroku CLI's `info`
  command to get the application name.
- Remove packaging changes previously made to convey gems along with
  parity for Traveling Ruby packaging.

While I suspect I may have been the only user to make use of environment
variables to specify the name of the development database, these changes
will require a major version update as they break backwards
compatibility.

Fix #91, #93, #96.

Gemfile

@@ -1,10 +1,6 @@
 source 'https://rubygems.org'
 
-gem "dotenv"
-gem "git"
-gem "rake"
-
 group :development do
-  gem "climate_control"
+  gem "rake"
   gem "rspec"
 end

lib/parity.rb

@@ -3,9 +3,6 @@
 require "parity/version"
 require "parity/environment"
 require "parity/usage"
-require "erb"
-require "git"
-require "dotenv"
 require "open3"
 require "pathname"
 require "uri"

lib/parity/backup.rb

@@ -65,15 +65,13 @@ def remote_db_backup_url
     end
 
     def development_db
-      YAML.load(parsed_database_yml).
+      YAML.load(database_yaml_file).
         fetch(DEVELOPMENT_ENVIRONMENT_KEY_NAME).
         fetch(DATABASE_KEY_NAME)
     end
 
-    def parsed_database_yml
-      Dotenv.load
-      yaml_file = IO.read(DATABASE_YML_RELATIVE_PATH)
-      ERB.new(yaml_file).result
+    def database_yaml_file
+      IO.read(DATABASE_YML_RELATIVE_PATH)
     end
   end
 end

lib/parity/environment.rb

@@ -14,8 +14,6 @@ def run
 
     private
 
-    GIT_REMOTE_SEGMENT_DELIMITER_REGEX = /[\/:]/
-    GIT_REMOTE_FILE_EXTENSION_REGEX = /\.git$/
     PROTECTED_ENVIRONMENTS = %w(development production)
 
     attr_accessor :environment, :subcommand, :arguments
@@ -94,19 +92,19 @@ def restore_confirmation_argument
     end
 
     def console
-      Kernel.system("heroku run rails console --remote #{environment}")
+      Kernel.system(command_for_remote("run rails console"))
     end
 
     def migrate
       Kernel.system(%{
-        heroku run rake db:migrate --remote #{environment} &&
-        heroku restart --remote #{environment}
+        #{command_for_remote('run rake db:migrate')} &&
+        #{command_for_remote('restart')}
       })
     end
 
     def tail
       Kernel.system(
-        "heroku logs --tail #{arguments.join(" ")} --remote #{environment}"
+        command_for_remote("logs --tail #{arguments.join(' ')}"),
       )
     end
 
@@ -125,20 +123,20 @@ def redis_cli
     end
 
     def raw_redis_url
-      @redis_to_go_url ||= Open3.capture3(
-        "heroku config:get REDIS_URL "\
-        "--remote #{environment}"
-      )[0].strip
+      @redis_to_go_url ||= Open3.
+        capture3(command_for_remote("config:get REDIS_URL"))[0].
+        strip
     end
 
-    def git_remote
-      Git.init.remote(environment).url
+    def heroku_app_name
+      @heroku_app_name ||= Open3.
+        capture3(command_for_remote("info"))[0].
+        split("\n")[0].
+        gsub(/(\s|=)+/, "")
     end
 
-    def heroku_app_name
-      git_remote.
-        split(GIT_REMOTE_SEGMENT_DELIMITER_REGEX).
-        last.sub(GIT_REMOTE_FILE_EXTENSION_REGEX, "")
+    def command_for_remote(command)
+      "heroku #{command} --remote #{environment}"
     end
 
     def run_migrations?

spec/parity/backup_spec.rb

@@ -1,5 +1,3 @@
-require "climate_control"
-
 require File.join(File.dirname(__FILE__), '..', '..', 'lib', 'parity')
 
 describe Parity::Backup do
@@ -17,35 +15,6 @@
       with(heroku_production_to_development_passthrough)
   end
 
-  context "with a database.yml that uses ERB and environment variables" do
-    around do |example|
-      ClimateControl.modify DEVELOPMENT_DATABASE_NAME: "erb_database_name" do
-        example.run
-      end
-    end
-
-    it "correctly parses database.yml" do
-      development_db = ENV["DEVELOPMENT_DATABASE_NAME"]
-      allow(IO).to receive(:read).and_return(database_with_erb_fixture)
-      allow(Kernel).to receive(:system)
-
-      Parity::Backup.new(from: "production", to: "development").restore
-
-      expect(Kernel).
-        to have_received(:system).
-        with(
-          drop_development_database_drop_command(db_name: development_db),
-        )
-      expect(Kernel).
-        to have_received(:system).
-        with(
-          heroku_production_to_development_passthrough(
-            db_name: development_db,
-          ),
-        )
-    end
-  end
-
   it "restores backups to staging from production" do
     allow(Kernel).to receive(:system)
 

spec/parity/environment_spec.rb

@@ -32,7 +32,7 @@
     expect(Kernel).to have_received(:system).with(heroku_backup)
   end
 
-  it "correctly connects to the Heroku app when the $PWD's name does not match the app's name (remote uses git:// protocol)" do
+  it "connects to the Heroku app when $PWD does not match the app name" do
     backup = stub_parity_backup
     stub_git_remote(base_name: "parity-integration", environment: "staging")
     allow(Parity::Backup).to receive(:new).and_return(backup)
@@ -49,26 +49,6 @@
     expect(backup).to have_received(:restore)
   end
 
-  it "correctly connects to the Heroku app when the $PWD's name does not match the app's name (remote uses https:// protocol)" do
-    backup = stub_parity_backup
-    stub_git_remote_for_https(
-      base_name: "parity-integration",
-      environment: "staging",
-    )
-    allow(Parity::Backup).to receive(:new).and_return(backup)
-
-    Parity::Environment.new("staging", ["restore", "production"]).run
-
-    expect(Parity::Backup).
-      to have_received(:new).
-      with(
-        from: "production",
-        to: "staging",
-        additional_args: "--confirm parity-integration-staging",
-      )
-    expect(backup).to have_received(:restore)
-  end
-
   it "restores backups from production to staging" do
     backup = stub_parity_backup
     stub_git_remote(environment: "staging")
@@ -379,23 +359,16 @@ def stub_migration_path_check(result)
   end
 
   def stub_git_remote(base_name: "parity", environment: "staging")
-    git_remote = instance_double(
-      "Git::Remote",
-      url: "git@heroku.com:#{base_name}-#{environment}.git",
-    )
-    git = instance_double("Git::Base")
-    allow(git).to receive(:remote).with("staging").and_return(git_remote)
-    allow(Git).to receive(:init).and_return(git)
-  end
-
-  def stub_git_remote_for_https(base_name: "parity", environment: "staging")
-    git_remote = instance_double(
-      "Git::Remote",
-      url: "https://git.heroku.com/#{base_name}-#{environment}.git",
-    )
-    git = instance_double("Git::Base")
-    allow(git).to receive(:remote).with("staging").and_return(git_remote)
-    allow(Git).to receive(:init).and_return(git)
+    allow(Open3).
+      to receive(:capture3).
+      with("heroku info --remote #{environment}").
+      and_return(
+        [
+          "=== #{base_name}-#{environment}\nAddOns: blahblahblah",
+          "",
+          {},
+        ],
+      )
   end
 
   def stub_parity_backup