Ruby でインストールが失敗しました: jekyll をインストールできません

概要

Ruby に依存する Jekyll を使用して GitHub ページをセットアップしようとしていました (ここのように)。残念ながら、インストールでちょっと失敗したようです（数回 sudo apt-get install Ruby-full と sudo apt-get Remove Ruby-full を実行した後…）

現在、コンピューター上に古いバージョンの Ruby (と思われる) が残っており、更新できません。現在の私のシステムの状態は次のとおりです。

$ ruby -v
ruby 2.7.0p0 (2019-12-25 revision 647ee6f091) [x86_64-linux-gnu]
$ gem -v
3.1.2

$ gem install jekyll
ERROR:  Error installing jekyll:
    The last version of sass-embedded (~> 1.54) to support your Ruby & RubyGems was 1.58.0. Try installing it with `gem install sass-embedded -v 1.58.0` and then running the current command again
    sass-embedded requires RubyGems version >= 3.3.22. The current RubyGems version is 3.1.2. Try 'gem update --system' to update RubyGems itself.

$ gem update --system
Updating rubygems-update
Successfully installed rubygems-update-3.4.6
Parsing documentation for rubygems-update-3.4.6
Done installing documentation for rubygems-update after 0 seconds
Parsing documentation for rubygems-update-3.4.6
Done installing documentation for rubygems-update after 0 seconds
Installing RubyGems 3.4.6
Traceback (most recent call last):
    5: from setup.rb:22:in `<main>'
    4: from setup.rb:22:in `require'
    3: from /home/jarret/gems/gems/rubygems-update-3.4.6/lib/rubygems.rb:1332:in `<top (required)>'
    2: from /home/jarret/gems/gems/rubygems-update-3.4.6/lib/rubygems.rb:1332:in `require'
    1: from /usr/lib/ruby/vendor_ruby/rubygems/defaults/operating_system.rb:49:in `<top (required)>'
/usr/lib/ruby/vendor_ruby/rubygems/defaults/operating_system.rb:50:in `<class:Specification>': undefined method `rubyforge_project=' for class `Gem::Specification' (NameError)
    3: from setup.rb:22:in `<main>'
    2: from setup.rb:22:in `require'
    1: from /home/jarret/gems/gems/rubygems-update-3.4.6/lib/rubygems.rb:1328:in `<top (required)>'
/home/jarret/gems/gems/rubygems-update-3.4.6/lib/rubygems.rb:1342:in `rescue in <top (required)>': undefined method `rubyforge_project=' for class `Gem::Specification' (NameError)
Loading the /usr/lib/ruby/vendor_ruby/rubygems/defaults/operating_system.rb file caused an error. This file is owned by your OS, not by rubygems upstream. Please find out which OS package this file belongs to and follow the guidelines from your OS to report the problem and ask for help.

$ gem env
RubyGems Environment:
  - RUBYGEMS VERSION: 3.1.2
  - RUBY VERSION: 2.7.0 (2019-12-25 patchlevel 0) [x86_64-linux-gnu]
  - INSTALLATION DIRECTORY: /home/jarret/gems
  - USER INSTALLATION DIRECTORY: /home/jarret/.gem/ruby/2.7.0
  - RUBY EXECUTABLE: /usr/bin/ruby2.7
  - GIT EXECUTABLE: /usr/bin/git
  - EXECUTABLE DIRECTORY: /home/jarret/gems/bin
  - SPEC CACHE DIRECTORY: /home/jarret/.gem/specs
  - SYSTEM CONFIGURATION DIRECTORY: /etc
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86_64-linux
  - GEM PATHS:
     - /home/jarret/gems
     - /home/jarret/.gem/ruby/2.7.0
     - /var/lib/gems/2.7.0
     - /usr/lib/ruby/gems/2.7.0
     - /usr/share/rubygems-integration/2.7.0
     - /usr/share/rubygems-integration/all
     - /usr/lib/x86_64-linux-gnu/rubygems-integration/2.7.0
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :backtrace => false
     - :bulk_threshold => 1000
  - REMOTE SOURCES:
     - https://rubygems.org/
  - SHELL PATH:
     - /home/jarret/gems/bin
     - /home/jarret/miniconda3/condabin
     - /usr/local/sbin
     - /usr/local/bin
     - /usr/sbin
     - /usr/bin
     - /sbin
     - /bin
     - /usr/games
     - /usr/local/games
     - /snap/bin
     - /opt/fiji/Fiji.app

多くの削除/インストールを試し、更新された gem や Ruby を試しました。これまでのところ何もロックを解除できませんでした。

解決策

Ruby3.0 を置き換えてみてください。sass1.58 は高度すぎて、ruby2.7 と互換性がない可能性があります。次の手順に従ってコマンドを実行してください。