brew install Freezing - macos

Question

I'm having trouble with brew install <PackageName>
I had macOS BigSur and could use commands like brew easily but in recent downgrade (Mojave) I can't do it anymore
it freeze about 60 second and reply with (If I getting it right) that can't update the main repository
CODE :
Updating Homebrew...
error: Not a valid ref: refs/remotes/origin/master
fatal: ambiguous argument 'refs/remotes/origin/master': unknown revision or path not in the working tree.
Use '--' to separate paths from revisions, like this:
'git <command> [<revision>...] -- [<file>...]'
fatal: Could not resolve HEAD to a revision
==> Homebrew has enabled anonymous aggregate formula and cask analytics.
Read the analytics documentation (and how to opt-out) here:
https://docs.brew.sh/Analytics
No analytics have been recorded yet (nor will be during this `brew` run).
==> Homebrew is run entirely by unpaid volunteers. Please consider donating:
https://github.com/Homebrew/brew#donations
==> Auto-updated Homebrew!
Updated 1 tap (homebrew/cask).
==> New Casks
8x8-work disk-expert guilded odbc-manager ubports-installer
diagnostics duplicate-file-finder hush pktriot
==> Updated Casks
Updated 352 casks.
==> Deleted Casks
adafruit-arduino beautune caramba-switcher
adobe-lens-profile-creator blue-jeans-browser-plugin
Warning: No available formula or cask with the name "htop".
==> Searching for similarly named formulae...
Error: No similarly named formulae found.
==> Searching for a previously deleted formula (in the last month)...
Error: No previously deleted formula found.
==> Searching taps on GitHub...
Error: No formulae found in taps.

Answer 1

Homebrew is managed by git repos. From the output, homebrew is detached and homebrew-core repo is missing.
Let's try following commands to fix the repos.
# Reset remote repo for Homebrew, the pkg manager itself
git -C "$(brew --repo)" remote set-url origin https://github.com/Homebrew/brew.git
# Reset origin for homebrew taps
BREW_TAPS="$(brew tap)"
for tap in core cask{,-fonts,-drivers,-versions}; do
if echo "$BREW_TAPS" | grep -qE "^homebrew/${tap}\$"; then
git -C "$(brew --repo homebrew/${tap})" remote set-url origin https://github.com/Homebrew/homebrew-${tap}.git
fi
done
brew update-reset
If it doesn't work, you may have to reinstall Homebrew.