$ brew update Error: homebrew-core is a shallow clone. To `brew update` first run: git -C "/usr/local/Homebrew/Library/Taps/homebrew/homebrew-core" fetch --unshallow 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. 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!
brew updateしようとしたらこんなメッセージが。
解決方法はメッセージに書いてある通り以下を実行する。何で起きたのかは不明
$ git -C "/usr/local/Homebrew/Library/Taps/homebrew/homebrew-core" fetch --unshallow
