rbenvでのRubyインストール失敗対応（cannot load such file -- psych）

概要

rbenvからの「Ruby3.2.1」インストールで
以下のエラーが発生していたため、その解決方法を記録しておきます。

Last 10 log lines:
	Check ext/psych/mkmf.log for more details.
*** Fix the problems, then remove these directories and try again if you want.
Generating RDoc documentation
/private/var/folders/gt/wrmndzvn7nqfx827qvt8k4zh0000gn/T/ruby-build.20230325134318.81087.mVBPCC/ruby-3.2.1/lib/yaml.rb:3: warning: It seems your ruby installation is missing psych (for YAML output).
To eliminate this warning, please install libyaml and reinstall your ruby.
uh-oh! RDoc had a problem:
cannot load such file -- psych

開発環境

• macOS Ventura 13.2.1
• MacBookPro M2 Pro

rbenvをインストール

$ brew install rbenv ruby-build

rbenvインストールは問題なかった

rbenvからRuby3.2.1をインストールしてみるが、失敗

$ rbenv install 3.2.1

To follow progress, use 'tail -f /var/folders/gt/wrmndzvn7nqfx827qvt8k4zh0000gn/T/ruby-build.20230325134318.81087.log' or pass --verbose
Downloading openssl-3.0.8.tar.gz...
-> https://dqw8nmjcqpjn7.cloudfront.net/6c13d2bf38fdf31eac3ce2a347073673f5d63263398f1f69d0df4a41253e4b3e
Installing openssl-3.0.8...
Installed openssl-3.0.8 to /Users/hoge/.rbenv/versions/3.2.1

Downloading ruby-3.2.1.tar.gz...
-> https://cache.ruby-lang.org/pub/ruby/3.2/ruby-3.2.1.tar.gz
Installing ruby-3.2.1...
ruby-build: using readline from homebrew

BUILD FAILED (macOS 13.2.1 using ruby-build 20230309)

Inspect or clean up the working tree at /var/folders/gt/wrmndzvn7nqfx827qvt8k4zh0000gn/T/ruby-build.20230325134318.81087.mVBPCC
Results logged to /var/folders/gt/wrmndzvn7nqfx827qvt8k4zh0000gn/T/ruby-build.20230325134318.81087.log

Last 10 log lines:
	Check ext/psych/mkmf.log for more details.
*** Fix the problems, then remove these directories and try again if you want.
Generating RDoc documentation
/private/var/folders/gt/wrmndzvn7nqfx827qvt8k4zh0000gn/T/ruby-build.20230325134318.81087.mVBPCC/ruby-3.2.1/lib/yaml.rb:3: warning: It seems your ruby installation is missing psych (for YAML output).
To eliminate this warning, please install libyaml and reinstall your ruby.
uh-oh! RDoc had a problem:
cannot load such file -- psych

run with --debug for full backtrace
make: *** [rdoc] Error 1

インストール失敗。
エラーメッセージ↓を確認したところ、libyamlに問題があった模様。
please install libyaml and reinstall your ruby.

libyamlをインストールしてみる

#### libyaml確認。（インストールされていなかった。）
$ brew info libyaml
==> libyaml: stable 0.2.5 (bottled)
YAML Parser
https://github.com/yaml/libyaml
Not installed
From: https://github.com/Homebrew/homebrew-core/blob/HEAD/Formula/libyaml.rb
License: MIT
==> Dependencies
Build: autoconf ✔, automake ✘, libtool ✘
==> Analytics
install: 2,507 (30 days), 193,777 (90 days), 1,024,167 (365 days)
install-on-request: 350 (30 days), 40,851 (90 days), 191,915 (365 days)
build-error: 1 (30 days)


#### libyamlをインストール
$ brew install libyaml

再度rbenvからRuby3.2.1をインストール

$ rbenv install 3.2.1

To follow progress, use 'tail -f /var/folders/gt/wrmndzvn7nqfx827qvt8k4zh0000gn/T/ruby-build.20230325140543.73012.log' or pass --verbose
Downloading openssl-3.0.8.tar.gz...
-> https://dqw8nmjcqpjn7.cloudfront.net/6c13d2bf38fdf31eac3ce2a347073673f5d63263398f1f69d0df4a41253e4b3e
Installing openssl-3.0.8...
Installed openssl-3.0.8 to /Users/hoge/.rbenv/versions/3.2.1

Downloading ruby-3.2.1.tar.gz...
-> https://cache.ruby-lang.org/pub/ruby/3.2/ruby-3.2.1.tar.gz
Installing ruby-3.2.1...
ruby-build: using readline from homebrew
ruby-build: using libyaml from homebrew
Installed ruby-3.2.1 to /Users/hoge/.rbenv/versions/3.2.1

問題なくインストールできた。

参考資料