エラー行が多い…Railsサーバが起動しない1。「Ignoring nokogiri-1.10.x because its extensions are not built.」


###  <font color='lightblue'>発生した背景</font>
久々に自分で作成したアプリケーションを起動しようとすると、以下のエラーが出力されて、アプリが起動されません。対応した手順を記録します。
（バージョンが合わないなどの問題もありましたが、こちらは別記事にしようと思います。）
非常に長いエラーのため、慎重に対応していく

###  <font color='lightblue'>再現手順/実行した内容</font>
アプリのrootpathで、rails -s」コマンド実行した際に、出力されたエラーです。

エラー１：

```
[staff@term]rails s
Ignoring nokogiri-1.10.1 because its extensions are not built. Try: gem pristine nokogiri --version 1.10.1
Ignoring bcrypt-3.1.12 because its extensions are not built. Try: gem pristine bcrypt --version 3.1.12
Ignoring bindex-0.7.0 because its extensions are not built. Try: gem pristine bindex --version 0.7.0
Ignoring bindex-0.5.0 because its extensions are not built. Try: gem pristine bindex --version 0.5.0
Ignoring binding_of_caller-0.8.0 because its extensions are not built. Try: gem pristine binding_of_caller --version 0.8.0
Ignoring bootsnap-1.4.3 because its extensions are not built. Try: gem pristine bootsnap --version 1.4.3
Ignoring bootsnap-1.4.1 because its extensions are not built. Try: gem pristine bootsnap --version 1.4.1
Ignoring bootsnap-1.4.0 because its extensions are not built. Try: gem pristine bootsnap --version 1.4.0
Ignoring bootsnap-1.3.2 because its extensions are not built. Try: gem pristine bootsnap --version 1.3.2
------- 一部割愛
```

エラー２：

```
Traceback (most recent call last):
	61: from bin/rails:3:in `<main>'
	60: from bin/rails:3:in `load'
	59: from /Users/ichikawadaisuke/projects/krown/bin/spring:15:in `<top (required)>'
	58: from /Users/ichikawadaisuke/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:70:in `require'
	57: from /Users/ichikawadaisuke/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:70:in `require'
	56: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/spring-2.0.2/lib/spring/binstub.rb:31:in `<top (required)>'
	55: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/spring-2.0.2/lib/spring/binstub.rb:31:in `load'
	54: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/spring-2.0.2/bin/spring:49:in `<top (required)>'
	53: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/spring-2.0.2/lib/spring/client.rb:30:in `run'
	52: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/spring-2.0.2/lib/spring/client/command.rb:7:in `call'
	51: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/spring-2.0.2/lib/spring/client/rails.rb:28:in `call'
	50: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/spring-2.0.2/lib/spring/client/rails.rb:28:in `load'
	49: from /Users/ichikawadaisuke/projects/krown/bin/rails:9:in `<top (required)>'
	48: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:291:in `require'
	47: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:257:in `load_dependency'
	46: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:291:in `block in require'
	45: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
	44: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require_with_bootsnap_lfi'
	43: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
	42: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `block in require_with_bootsnap_lfi'
	41: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require'
	40: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/railties-5.2.3/lib/rails/commands.rb:18:in `<main>'
	39: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/railties-5.2.3/lib/rails/command.rb:46:in `invoke'
	38: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/railties-5.2.3/lib/rails/command/base.rb:65:in `perform'
	37: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/thor-0.20.3/lib/thor.rb:387:in `dispatch'
	36: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/thor-0.20.3/lib/thor/invocation.rb:126:in `invoke_command'
	35: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/thor-0.20.3/lib/thor/command.rb:27:in `run'
	34: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/railties-5.2.3/lib/rails/commands/server/server_command.rb:142:in `perform'
	33: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/railties-5.2.3/lib/rails/commands/server/server_command.rb:142:in `tap'
	32: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/railties-5.2.3/lib/rails/commands/server/server_command.rb:145:in `block in perform'
	31: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:291:in `require'
	30: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:257:in `load_dependency'
	29: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:291:in `block in require'
	28: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
	27: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require_with_bootsnap_lfi'
	26: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
	25: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `block in require_with_bootsnap_lfi'
	24: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require'
	23: from /Users/ichikawadaisuke/projects/krown/config/application.rb:7:in `<main>'
	22: from /Users/ichikawadaisuke/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bundler-2.0.1/lib/bundler.rb:114:in `require'
	21: from /Users/ichikawadaisuke/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bundler-2.0.1/lib/bundler/runtime.rb:65:in `require'
	20: from /Users/ichikawadaisuke/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bundler-2.0.1/lib/bundler/runtime.rb:65:in `each'
	19: from /Users/ichikawadaisuke/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bundler-2.0.1/lib/bundler/runtime.rb:76:in `block in require'
	18: from /Users/ichikawadaisuke/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bundler-2.0.1/lib/bundler/runtime.rb:76:in `each'
	17: from /Users/ichikawadaisuke/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bundler-2.0.1/lib/bundler/runtime.rb:81:in `block (2 levels) in require'
	16: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
	15: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require_with_bootsnap_lfi'
	14: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
	13: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `block in require_with_bootsnap_lfi'
	12: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require'
	11: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/uglifier-4.1.20/lib/uglifier.rb:5:in `<main>'
	10: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:291:in `require'
	 9: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:257:in `load_dependency'
	 8: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:291:in `block in require'
	 7: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
	 6: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require_with_bootsnap_lfi'
	 5: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
	 4: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `block in require_with_bootsnap_lfi'
	 3: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/bootsnap-1.4.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require'
	 2: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/execjs-2.7.0/lib/execjs.rb:4:in `<main>'
	 1: from /Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/execjs-2.7.0/lib/execjs.rb:5:in `<module:ExecJS>'
/Users/ichikawadaisuke/projects/krown/vendor/ruby/2.5.0/gems/execjs-2.7.0/lib/execjs/runtimes.rb:58:in `autodetect': Could not find a JavaScript runtime. See https://github.com/rails/execjs for a list of available runtimes. (ExecJS::RuntimeUnavailable)
```

###  <font color='lightblue'>対応方法</font>
エラーの出力量が非常に多いため、環境を再構築する方が早いかもしれないと考えたが、時間を決めて対応してみることに。

- ①記述に従い、「gem pristine nokogiri --version 1.10.1」を実行してみる。
 - bundle execを付加して実行してみる。
 - bundle install --path vendorの実行
 - 結果 -> 同じエラーが出力される。
- ②背景から一度「bundle update」を実行してみる。
 - 結果 -> <font color='blue'>エラー２だけが出力されるようになった</font>

背景として他のアプリを起動するため、homebrewコマンドでインストールを実施した際に、途中で失敗。これに伴い、osのリカバリを実施したのち、XcodeなどRailsが関係するアプリケーションを再設定した。
エラー１が解消したのは、これらの操作によってGem環境も×になったため、「bundle install」で解消したものと想定する

エラー２の対応方法については別記事にて掲載する。