Rails Tutorialエラーメモ(1~3章)

Webアプリ作成のためRails Tutorialを始めたので，発生したエラーをメモしていきたいと思います．
随時更新していきます^_^

開発環境

• AWS cloud9
• Ruby 2.4.1
• Rails 5.1.4

1章

bundle install時にpgエラーがでる．

Gemfileを書き換えbundle installを行った際，pgがうまくインストールされず以下のエラーが発生．

An error occurred while installing pg (0.20.0), and Bundler cannot continue.

解決策

調べてみると，libpq-fe.hが無くエラーを吐いてるっぽい．postgresqlをインストールすると自動で入るらしいので，yumでインストールする．

$ sudo yum install postgresql

2章

StandardError: An error has occurred, this and all later migrations canceled:

db:migrateした際に発生したエラー．既にtablesが存在し，うまくmigrateされない．

SQLite3::SQLException: table "microposts" already exists: CREATE TABLE "microposts" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, "content" text, "user_id" integer, "created_at" datetime NOT NULL, "updated_at" datetime NOT NULL)
:
bin/rails:3:in `load'
bin/rails:3:in `<main>'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)

解決策

dbを一旦リセットする．

$ rails db:migrate:reset

再びmigrateする．

$ rails db:migrate

3章

herokuにデプロイしたらMethod Not Allowedとでる．

解決策

heroku apps:infoして，Web URLを開く．僕の場合，Git URLを開いたのが原因でした．

rails testでversion': undefined method `[]' for nil:NilClass (NoMethodError)とエラーがでる．

rails testを実行した際，テストは成功したものの，以下のようなエラーが発生．

/usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/tmux/client.rb:12:in `version': undefined method `[]' for nil:NilClass (NoMethodError)
        from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/tmux.rb:69:in `_check_available'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/base.rb:59:in `initialize'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:100:in `new'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:100:in `_add'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:62:in `block (2 levels) in detect'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:60:in `each'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:60:in `detect'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:60:in `block in detect'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:59:in `each'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:59:in `detect'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier.rb:180:in `_detect_or_add_notifiers'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier.rb:198:in `_activate'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier.rb:87:in `initialize'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier.rb:42:in `new'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier.rb:42:in `connect'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/guard-2.13.0/lib/guard/notifier.rb:11:in `connect'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/guard-2.13.0/lib/guard/notifier.rb:31:in `notify'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/guard-compat-1.2.1/lib/guard/compat/plugin.rb:113:in `notify'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/guard-minitest-2.4.4/lib/guard/minitest/notifier.rb:31:in `notify'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/guard-minitest-2.4.4/lib/guard/minitest/reporter.rb:10:in `report'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/minitest-5.11.3/lib/minitest.rb:808:in `each'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/minitest-5.11.3/lib/minitest.rb:808:in `report'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/minitest-5.11.3/lib/minitest.rb:141:in `run'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/minitest-5.11.3/lib/minitest.rb:63:in `block in autorun'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/spring-2.0.2/lib/spring/application.rb:171:in `fork'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/spring-2.0.2/lib/spring/application.rb:171:in `serve'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/spring-2.0.2/lib/spring/application.rb:141:in `block in run'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/spring-2.0.2/lib/spring/application.rb:135:in `loop'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/spring-2.0.2/lib/spring/application.rb:135:in `run'
        from /usr/local/rvm/gems/ruby-2.4.1/gems/spring-2.0.2/lib/spring/application/boot.rb:19:in `<top (required)>'
        from /usr/local/rvm/rubies/ruby-2.4.1/lib/ruby/site_ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
        from /usr/local/rvm/rubies/ruby-2.4.1/lib/ruby/site_ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
        from -e:1:in `<main>'

解決策

Railsのversionが5.1.4だとminitestは5.10.X系にする必要があるらしい． よってGemfileにgem 'minitest','~>5.10.1'を追加．

group :test do
  gem 'rails-controller-testing', '1.0.2'
  gem 'minitest-reporters',       '1.1.14'
  gem 'guard',                    '2.13.0'
  gem 'guard-minitest',           '2.4.4'
  gem 'minitest','~>5.10.1'
end

bundle installする．

参考サイト

goo.gl

qiita.com

qiita.com