brewで更新しようとしたら何か出た

更新しようとしたらなんか出た。

$ brew update
Error: 
homebrew-core is a shallow clone.
homebrew-cask is a shallow clone.
To `brew update`, first run:
git -C /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core fetch --unshallow
git -C /usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask fetch --unshallow
These commands may take a few minutes to run due to the large size of the repositories.
This restriction has been made on GitHub's request because updating shallow
clones is an extremely expensive operation due to the tree layout and traffic of
Homebrew/homebrew-core and Homebrew/homebrew-cask. We don't do this for you
automatically to avoid repeatedly performing an expensive unshallow operation in
CI systems (which should instead be fixed to not use shallow clones). Sorry for
the inconvenience!

なにこれ。

• Homebrew で Error: homebrew-core is a shallow clone が出て brew update が実行できない問題

今までHomebrewの更新はshallow cloneで行っていたが、GitHubの負荷が大きいため、完全なcloneに変更になった。 ので、今のshallowリポジトリを完全なものにするgit -C XXX fetch --unshallowして、ね。

git -C /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core fetch --unshallow
git -C /usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask fetch --unshallow

ということらしい。