How to install an old package version with brew

Sometimes you need to roll back to a previous version of a brew package. If the brew package maintainers do versioning this is as easy as typing brew install <packageName>@1.2.3. Often times, there's no versioning system though and the only available version is the latest one.

In previous brew versions you could install a package by directly linking to the GitHub repo that hosts the Formula/<packageName>.rb file. The repository is usually called homebrew-<packageName> and you can browse through the git commits to find an old Formula/<packageName>.rb file. For example, you could install an old version of EOSIO.CDT by doing:

brew remove eosio.cdt
brew install https://raw.githubusercontent.com/EOSIO/homebrew-eosio.cdt/d0f0320017315bd5ac69aa1e1ce001c6567af6b3/eosio.cdt.rb

Recent brew versions, however, verschlimmbessert this behavior and the brew police tells you that you're not allowed to do this anymore.

Error: Calling Installation of <packageName> from a GitHub commit URL is disabled! Use 'brew extract <packageName>' to stable tap on GitHub instead.

What to do now?

Just do what the error message hints at and use brew extract to stable tap on GitHub. 🙃

To save you some time, here’s how to do it:

1. You create a local “tap” — which I assume is something like a local brew repository
2. You extract the desired version of the package into this local tap
3. You install your local tap

# use $USER variable to mimick userName/repoName structure
# this does not actually create any git repositories
# 1. create a new tap
brew tap-new $USER/local-<packageName>
# 2. extract into local tap
brew extract --version=1.2.3 <packageName> $USER/local-<packageName>
# 3. run brew install@version as usual
brew install <packageName>@1.2.3

Originally published at https://cmichel.io/how-to-install-an-old-package-version-with-brew/