RMagickがインストール出来ない

Question

ポートフォリオに画像アップロード機能を追加したく
RMagickをインストールしようとした際にエラーが出てしまいました。

長く解決することが出来ていないので、ご教授頂ければ幸いです。

【エラー内容】

Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    current directory: /Users/onoderakoudai/Desktop/Sentou/vendor/bundle/ruby/2.5.0/gems/rmagick-2.16.0/ext/RMagick
/Users/onoderakoudai/.rbenv/versions/2.5.1/bin/ruby -r ./siteconf20181212-59454-2mils2.rb extconf.rb
checking for clang... yes
checking for Magick-config... yes
checking for outdated ImageMagick version (<= 6.4.9)... no
checking for presence of MagickWand API (ImageMagick version >= 6.9.0)... no
Package MagickWand was not found in the pkg-config search path.
Perhaps you should add the directory containing `MagickWand.pc'
to the PKG_CONFIG_PATH environment variable
No package 'MagickWand' found
Package MagickWand was not found in the pkg-config search path.
Perhaps you should add the directory containing `MagickWand.pc'
to the PKG_CONFIG_PATH environment variable
No package 'MagickWand' found
Package MagickWand was not found in the pkg-config search path.
Perhaps you should add the directory containing `MagickWand.pc'
to the PKG_CONFIG_PATH environment variable
No package 'MagickWand' found
Package MagickWand was not found in the pkg-config search path.
Perhaps you should add the directory containing `MagickWand.pc'
to the PKG_CONFIG_PATH environment variable
No package 'MagickWand' found
checking for Ruby version >= 1.8.5... yes
Package MagickCore was not found in the pkg-config search path.
Perhaps you should add the directory containing `MagickCore.pc'
to the PKG_CONFIG_PATH environment variable
No package 'MagickCore' found
Can't install RMagick 2.16.0. Can't find the ImageMagick library or one of the dependent libraries. Check the mkmf.log file for more detailed information.

*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
        --with-opt-dir
        --without-opt-dir
        --with-opt-include
        --without-opt-include=${opt-dir}/include
        --with-opt-lib
        --without-opt-lib=${opt-dir}/lib
        --with-make-prog
        --without-make-prog
        --srcdir=.
        --curdir
        --ruby=/Users/onoderakoudai/.rbenv/versions/2.5.1/bin/$(RUBY_BASE_NAME)

To see why this extension failed to compile, please check the mkmf.log which can be found here:

  /Users/onoderakoudai/Desktop/Sentou/vendor/bundle/ruby/2.5.0/extensions/x86_64-darwin-17/2.5.0-static/rmagick-2.16.0/mkmf.log

extconf failed, exit code 1

Gem files will remain installed in /Users/onoderakoudai/Desktop/Sentou/vendor/bundle/ruby/2.5.0/gems/rmagick-2.16.0 for inspection.
Results logged to /Users/onoderakoudai/Desktop/Sentou/vendor/bundle/ruby/2.5.0/extensions/x86_64-darwin-17/2.5.0-static/rmagick-2.16.0/gem_make.out

An error occurred while installing rmagick (2.16.0), and Bundler cannot continue.
Make sure that `gem install rmagick -v '2.16.0' --source 'https://rubygems.org/'` succeeds before bundling.

In Gemfile:
  rmagick

【実行したこと】

brew uninstall imagemagic

でアンインストールをするも、brew install imagemagick@6でエラー。

そこで、

blow doctor

を実行したところ

Warning: Broken symlinks were found. Remove them with `brew prune`:
  /usr/local/bin/code

と表示されたので、

brew prune /usr/local/bin/code

を実行しシンボリックを削除しました。

そのお陰か、brew install imagemagick@6が成功しました。

しかし、Gemgileにgem 'rmagick'を記載し、bundle installをすると

上記のエラーが表示されてしまいます。。。

brew info imagemagick

を実行し、バージョンを確認したところ、

imagemagick: stable 7.0.8-16 (bottled), HEAD

と表示され、なぜか7系のようです。
しかし、

/usr/local/Cellar

を確認してみると、imagemagick@6しかありません。。。

【参考記事】
https://qiita.com/fumi_042/items/55be8fb37cc23325b7c2
https://qiita.com/unsoluble_sugar/items/acaffa6d0e28c3c24934
https://qiita.com/sho012b/items/362abe993248c686fcf4
https://qiita.com/niwasawa/items/1144f20a9f2de4b76977

Answer 1

7系は存在してませんでしたが、brew link --force imagemagick@6を実行することで解決することが出来ました！