Homebrew fails on MacOS Big Sur

I upgraded from Mohave to Big Sur and found that homebrew is not working any more. I installed the command line tools using the command

xcode-select --install

After I run brew list, I get the following error

~ brew list
Traceback (most recent call last):
	11: from /usr/local/Homebrew/Library/Homebrew/brew.rb:23:in `<main>'
	10: from /usr/local/Homebrew/Library/Homebrew/brew.rb:23:in `require_relative'
	 9: from /usr/local/Homebrew/Library/Homebrew/global.rb:37:in `<top (required)>'
	 8: from /usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.3/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
	 7: from /usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.3/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
	 6: from /usr/local/Homebrew/Library/Homebrew/os.rb:3:in `<top (required)>'
	 5: from /usr/local/Homebrew/Library/Homebrew/os.rb:21:in `<module:OS>'
	 4: from /usr/local/Homebrew/Library/Homebrew/os/mac.rb:58:in `prerelease?'
	 3: from /usr/local/Homebrew/Library/Homebrew/os/mac.rb:24:in `version'
	 2: from /usr/local/Homebrew/Library/Homebrew/os/mac.rb:24:in `new'
	 1: from /usr/local/Homebrew/Library/Homebrew/os/mac/version.rb:26:in `initialize'
/usr/local/Homebrew/Library/Homebrew/version.rb:368:in `initialize': Version value must be a string; got a NilClass () (TypeError)

I tried by deleting the folder /Library/Developer/CommandLineTools and installing the Command Line Tools for Xcode 12.3 beta but still I am getting the same error. Is there any way to make brew work?

You should update brew;

brew update-reset

I had the same problem. Try upgrading brew - this solved it for me.

brew upgrade

I have solved my problem reinstalling brew with this script (install.sh):

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"

Then:

brew --version

output:

Homebrew 3.0.1
Homebrew/homebrew-core (git revision 47e5d; last commit 2021-02-14)

Then just proceed with: xcode-select --install

After upgrading brew

brew upgrade

I got the following message:

Your Command Line Tools (CLT) does not support macOS 11.
It is either outdated or was modified.
Please update your Command Line Tools (CLT) or delete it if no updates are 
available.
Update them from Software Update in System Preferences or run:
  softwareupdate --all --install --force

If that doesn't show you any updates, run:
  sudo rm -rf /Library/Developer/CommandLineTools
  sudo xcode-select --install

Alternatively, manually download them from:
  https://developer.apple.com/download/more/.

Error: An exception occurred within a child process:

According to the instructions I ran the following commands:

sudo rm -rf /Library/Developer/CommandLineTools
sudo xcode-select --install

and again ran

brew upgrade

And finally it worked.

You should update brew;

brew update-reset

If you run brew upgrade still meet the error, maybe you should run brew update first.

My experience is:

1. brew update
2. brew doctor
3. brew upgrade

When I follow @andrmu instructions, I received an error stating Homebrew: Your CLT does not support macOS 11.0.. I had to first follow the instructions to clean upgrade my command line tools as per the top answer on this issue, then it worked..

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"

This worked for me

I had the same problem, "brew update" wouldn't work, "brew upgrade" also didn't work, did the following:

> brew update-reset

and then

> brew upgrade

Now working fine.

Cheers,

H

After brew upgrade this did the trick to avoid tmp/mysql.sock error. Use commandline command:

sudo chmod -R 0777 /usr/local/var/mysql/