Can't update or upgrade Homebrew

Question

I can no longer run either brew upgrade or brew update: both abort with

Error: homebrew-core is a shallow clone. To `brew update` first run:   git -C "/usr/local/Homebrew/Library/Taps/homebrew/homebrew-core" fetch --unshallow 

and if I follow this suggestion and run git ... --unshallow and then try brew update or brew upgrade I still get the same error message.

If I then try the command again (maybe I didn't do it right the first time?) I get

fatal: --unshallow on a complete repository does not make sense

How do I get past this error message to run brew upgrade or brew update without errors?

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HOMEBREW_VERSION: 2.6.0-82-gde1afcb ORIGIN: https://github.com/Homebrew/brew.git HEAD: de1afcbfc58fb3cd5779bd8fbb6b9995700dda4c Last commit: 30 hours ago Core tap ORIGIN: https://github.com/Homebrew/homebrew-core Core tap HEAD: a7c63b0f7f7ae416a2f961b263155281759ac3a7 Core tap last commit: 29 hours ago Core tap branch: master HOMEBREW_PREFIX: /usr/local HOMEBREW_CASK_OPTS: [] HOMEBREW_DISPLAY: /private/tmp/com.apple.launchd.FwPJPzeLfq/org.macosforge.xquartz:0 HOMEBREW_EDITOR: /usr/local/bin/bbedit HOMEBREW_MAKE_JOBS: 4 HOMEBREW_NO_ANALYTICS: set HOMEBREW_NO_EMOJI: set Homebrew Ruby: 2.6.3 => /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/bin/ruby CPU: quad-core 64-bit haswell Clang: 12.0 build 1200 Git: 2.29.2 => /usr/local/bin/git Curl: 7.64.1 => /usr/bin/curl Java: 1.8.0_172 macOS: 10.15.7-x86_64 CLT: 12.0.32.27 Xcode: 12.2 XQuartz: 2.7.11 => /opt/X11 

Answer 1

It's asking you to unshallow both homebrew-core and homebrew-cask with:

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

Answer 2

Nothing worked with me until I did:

cd /usr/local/Homebrew/Library/Taps/homebrew/ rm -rf homebrew-core git clone https://github.com/Homebrew/homebrew-core.git