Cleanup and refactoring (heroku#1600)

* Delete unused file

This code is unused

* Refactor Lockfile Error

Previously, the existence check for a `Gemfile.lock` was enforced by creating a "language pack" that is checked and executed only if the Gemfile.lock file does not exist. The location for this logic doesn't need to be tied to a lanugage pack.

* Dont emit warning (from grep) when Gemfile.lock does not exist

Fixes this output:

```
remote: -----> Building on the Heroku-24 stack
remote: -----> Using buildpack: https://github.com/heroku/heroku-buildpack-ruby#schneems/every-bundler-version
remote: -----> Ruby app detected
remote: grep: /tmp/build_cdf9bd69/Gemfile.lock: No such file or directory
remote:
remote:  !
remote:  !     Gemfile.lock required. Please check it in.
remote:  !
remote:  !     Push rejected, failed to compile Ruby app.
```

* Remove false documentation 

Neither detect or release use Ruby for logic:

```
#!/bin/sh

APP_DIR=$1

if [ -f "$APP_DIR/Gemfile" ]; then
  echo "Ruby"
  exit 0
else
  exit 1
fi
$ cat bin/release
#!/usr/bin/env bash

set -euo pipefail

BUILD_DIR="${1:-}"
RELEASE_FILE="${BUILD_DIR}/tmp/heroku-buildpack-release-step.yml"

# Whilst the release file is always written by the buildpack, some apps use
# third-party slug cleaner buildpacks to remove this and other files, so we
# cannot assume it still exists by the time the release step runs.
if [[ -f "${RELEASE_FILE}" ]]; then
  cat "${RELEASE_FILE}"
fi
```

The cache path is a required argument

* Rename `build_path` to `app_path`

From the perspective of the buildpack the build happens in the application path. The word "build" is overloaded and can be confusing. The application directory has more specificity.

* Remove stray comment

* Remove unused env var

* Remove whitespace

* Remove unused variable

* Prefer kwargs

* Standardize on Pathname as the language pack input

* Extract Dir.chdir(app_path)

The expectation is that the language pack is called in the application directory. We can do this before it is invoked, remove extra calls sprinkled throughout.

* Update HEREDOC to ideomatic format

The `<<~` heredoc is indentation aware and was not available when a lot of these `<<-` heredocs were added.

* Whitespace

Author: schneems

bin/support/bash_functions.sh

@@ -74,7 +74,8 @@ detect_needs_java()
   if which_java; then
     return $skip_java_install
   fi
-  grep "(jruby " "$gemfile_lock" --quiet
+
+  grep "(jruby " "$gemfile_lock" --quiet &> /dev/null
 }
 
 # Runs another buildpack against the build dir

bin/support/ruby_compile

@@ -19,8 +19,12 @@ HerokuBuildReport.set_global(
 ).tap(&:clear!)
 
 begin
+  app_path = Pathname(ARGV[0])
+  cache_path = Pathname(ARGV[1])
+  Dir.chdir(app_path)
+
   LanguagePack::ShellHelpers.initialize_env(ARGV[2])
-  if pack = LanguagePack.detect(ARGV[0], ARGV[1])
+  if pack = LanguagePack.detect(app_path: app_path, cache_path: cache_path)
     pack.topic("Compiling #{pack.name}")
     pack.compile
   end

bin/support/ruby_test-compile

@@ -19,7 +19,11 @@ require "language_pack/test"
 include LanguagePack::ShellHelpers
 
 begin
-  if pack = LanguagePack.detect(ARGV[0], ARGV[1])
+  app_path = Pathname(ARGV[0])
+  cache_path = Pathname(ARGV[1])
+  Dir.chdir(app_path)
+
+  if pack = LanguagePack.detect(app_path: app_path, cache_path: cache_path)
     LanguagePack::ShellHelpers.initialize_env(ARGV[2])
     pack.topic("Setting up Test for #{pack.name}")
     pack.compile

lib/heroku_build_report.rb

@@ -36,7 +36,7 @@ def capture(metrics = {})
         return if key.nil? || key.to_s.strip.empty?
 
         key = key&.strip
-        raise "Key  cannot be empty (#{key.inspect} => #{value})" if key.nil? || key.empty?
+        raise "Key cannot be empty (#{key.inspect} => #{value})" if key.nil? || key.empty?
 
         # Don't serialize complex values by accident
         if complex_object?(value)

lib/language_pack.rb

@@ -1,22 +1,24 @@
 require "pathname"
 require 'benchmark'
 
+require 'language_pack/shell_helpers'
+
 # General Language Pack module
 module LanguagePack
   module Helpers
   end
 
   # detects which language pack to use
-  # @param [Array] first argument is a String of the build directory
-  # @return [LanguagePack] the {LanguagePack} detected
-  def self.detect(*args)
-    Dir.chdir(args.first)
+  def self.detect(app_path:, cache_path:)
+    if !File.exist?("Gemfile.lock")
+      raise BuildpackError.new("Gemfile.lock required. Please check it in.")
+    end
 
-    pack = [ NoLockfile, Rails8, Rails7, Rails6, Rails5, Rails42, Rails41, Rails4, Rails3, Rails2, Rack, Ruby ].detect do |klass|
+    pack = [ Rails8, Rails7, Rails6, Rails5, Rails42, Rails41, Rails4, Rails3, Rails2, Rack, Ruby ].detect do |klass|
       klass.use?
     end
 
-    return pack ? pack.new(*args) : nil
+    return pack ? pack.new(app_path: app_path, cache_path: cache_path) : nil
   end
 end
 
@@ -25,7 +27,6 @@ def self.detect(*args)
 
 require 'heroku_build_report'
 
-require 'language_pack/shell_helpers'
 require "language_pack/helpers/plugin_installer"
 require "language_pack/helpers/stale_file_cleaner"
 require "language_pack/helpers/rake_runner"
@@ -39,12 +40,10 @@ def self.detect(*args)
 require "language_pack/rack"
 require "language_pack/rails2"
 require "language_pack/rails3"
-require "language_pack/disable_deploys"
 require "language_pack/rails4"
 require "language_pack/rails41"
 require "language_pack/rails42"
 require "language_pack/rails5"
 require "language_pack/rails6"
 require "language_pack/rails7"
 require "language_pack/rails8"
-require "language_pack/no_lockfile"

lib/language_pack/base.rb

@@ -9,7 +9,6 @@
 require "language_pack/fetcher"
 
 Encoding.default_external = Encoding::UTF_8 if defined?(Encoding)
-ENV["BPLOG_PREFIX"] = "buildpack.ruby"
 
 # abstract class that all the Ruby based Language Packs inherit from
 class LanguagePack::Base
@@ -21,23 +20,19 @@ class LanguagePack::Base
   MULTI_ARCH_STACKS    = ["heroku-24"]
   KNOWN_ARCHITECTURES  = ["amd64", "arm64"]
 
-  attr_reader :build_path, :cache, :stack
+  attr_reader :app_path, :cache, :stack
 
-  # changes directory to the build_path
-  # @param [String] the path of the build dir
-  # @param [String] the path of the cache dir this is nil during detect and release
-  def initialize(build_path, cache_path = nil)
-    @build_path    = build_path
+  def initialize(app_path: , cache_path: )
+    @app_path = app_path
     @stack         = ENV.fetch("STACK")
     @cache         = LanguagePack::Cache.new(cache_path)
     @metadata      = LanguagePack::Metadata.new(@cache)
     @bundler_cache = LanguagePack::BundlerCache.new(@cache, @stack)
-    @id            = Digest::SHA1.hexdigest("#{Time.now.to_f}-#{rand(1000000)}")[0..10]
     @fetchers      = {:buildpack => LanguagePack::Fetcher.new(VENDOR_URL) }
     @arch = get_arch
     @report = HerokuBuildReport::GLOBAL
 
-    Dir.chdir build_path
+    Dir.chdir app_path
   end
 
   def get_arch
@@ -54,7 +49,7 @@ def get_arch
     arch
   end
 
-  def self.===(build_path)
+  def self.===(app_path)
     raise "must subclass"
   end
 
@@ -134,7 +129,7 @@ def setup_language_pack_environment
   end
 
   def add_to_profiled(string, filename: "ruby.sh", mode: "a")
-    profiled_path = "#{build_path}/.profile.d/"
+    profiled_path = "#{app_path}/.profile.d/"
 
     FileUtils.mkdir_p profiled_path
     File.open("#{profiled_path}/#{filename}", mode) do |file|

lib/language_pack/disable_deploys.rb

@@ -38,6 +38,4 @@ def setup_profiled(**args)
     super(**args)
     set_env_default "RACK_ENV", "production"
   end
-
 end
-

lib/language_pack/no_lockfile.rb

@@ -14,8 +14,8 @@ def self.use?
     return is_rails2
   end
 
-  def initialize(*args)
-    super(*args)
+  def initialize(app_path: , cache_path: )
+    super(app_path: app_path, cache_path: cache_path)
     @rails_runner = LanguagePack::Helpers::RailsRunner.new
   end
 
@@ -57,11 +57,11 @@ def compile
 
   def best_practice_warnings
     if env("RAILS_ENV") != "production"
-      warn(<<-WARNING)
-You are deploying to a non-production environment: #{ env("RAILS_ENV").inspect }.
-This is not recommended.
-See https://devcenter.heroku.com/articles/deploying-to-a-custom-rails-environment for more information.
-WARNING
+      warn(<<~WARNING)
+        You are deploying to a non-production environment: #{ env("RAILS_ENV").inspect }.
+        This is not recommended.
+        See https://devcenter.heroku.com/articles/deploying-to-a-custom-rails-environment for more information.
+      WARNING
     end
     super
   end
@@ -84,5 +84,4 @@ def setup_profiled(**args)
       set_env_default key, value
     end
   end
-
 end