How to Pin an Homebrew Dependency

Sometime you need to pin a dependency to a specific version, but if the dependency has not all the version listed it can be tricky.

The formula

Homebrew knows how to install packages by looking at the package formula. A formula is is a package definition, written in Ruby. Formulas for packages are located in the homebrew-core repository; so if you want to look at the information for a formula (for example wget) you can simply go in the repository and look at the formula definition. In there you can find all the info for the package like dependencies, how to install it, if there are precompiled binaries (called bottles) already available for the operating system brew is running on.

Pin a package to a version

To pin a package (locking it to a specific version) you can use the pin subcommandto prevent Homebrew from updating. From the command line, you can write (using again wget as example: brew pin wget

After this, Homebrew will not update the wget package unless you remove the pin, thus preventing unwanted updates.

Unpin a package

After a package is pinned Homebrew prevents it from being upgrade. Usually you want to prevent updates for a limited amount of time and update it at a later time. To update a pinned package you will need to use the unpin command; this instructs Homebrew to remove the lock on the version of the package and treat it as a normal package.

Bonus: Install (and pin) a specific version of a package

Write about how to install a version:

• by using brew install [email protected]
• by downloading and older version of a formula from GitHub

How to update

To update our pinned formula we need to remove the lock that fixes the version. It is only a matter of running brew unpin wget (continuing to use wget as example). Now we can run our usual brew install [email protected] to update to the newer desired version and the run brew pin wget again.