git – How to remove the shallow clone warning from HomeBrew

git – How to remove the shallow clone warning from HomeBrew

As of Oct 2020 Homebrew no longer creates shallow clones when being installed, and as of Dec 2020 updating existing shallow clones is not allowed either.

(This makes the original question about silencing the warning moot).

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If a shallow clone is configured, a message containing text like the below will be shown:

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

It is now required to perform the unshallow process by running the git command(s) in the error message.

Note: This process may take a long time to complete without providing feedback.

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For some details about the motivation for this change, see this discussion on Homebrews GitHub page, specifically:

There are two major downsides of shallow cloning:

1. It places a massive computation burden on GitHubs servers, which have to dynamically compute a fresh delta between what you have and the latest commit, on every brew update. (With full clones, GitHub can simply send you all the commits that happened after your last pull, and your local Git client takes care of the rest.)
2. Because of [1], it makes it far more likely that GitHub will rate-limit Homebrew operations, which will make it suck for everyone.

^{–gromgit Dec 5, 2020, 12:29 AM EST}

And also this additional text added to the error message:

This restriction has been made on GitHubs 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.

Under the cover Homebrew uses Git for version control, and a shallow clone
is one that doesnt contain all history revisions/commits, for efficiency and data volume.

Actually, in most cases the warning can be safely ignored, as the formulae being searched for probably isnt available.

But if youre really looking for some formulae which might existed in the past, Just do what it suggests:

To get complete history run:

git -C $(brew --repo homebrew/core) fetch --unshallow

This way Homebrew could search for formula that existed only in the past but removed at some point.

git – How to remove the shallow clone warning from HomeBrew

I would advise against unshallowing the clone because it cramps disk space, makes the lookups slower and enables you only to install obsolete or unmaintaned applications.

There is currently no way to silence this warning. It was proposed in this Github issue but then ignored.

The function deleted_reason which prints the message contains a silent argument but afaik there is no way to use to use something like silent from the CLI commands which later call deleted_reason.