brew cannot find ANY packages

Question

I just got my Mac Pro from the shop after hard drive failure. I am trying to install my environment again.

I installed homebrew from the current link on the homebrew website:

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

but I cannot install ANY package. Brew cannot find ANYTHING.

 ~ brew install rbenv
Error: No available formula with the name "rbenv"
==> Searching for a previously deleted formula (in the last month)...
Error: No previously deleted formula found.
==> Searching for similarly named formulae...
Error: No similarly named formulae found.
==> Searching taps...
==> Searching taps on GitHub...
Error: No formulae found in taps.

What is wrong?

Answer 1

I had the same issue and I was able to solve it by running the doctor command and follow the steps which need to be updated there.

My homebrew-core was not at the master branch.

brew doctor 
git -C $(brew --repo homebrew/core) checkout master

And that's it. After that, I was able to run the rbenv install command.