Fix Cellar versioned links in virtualenvs

fixvenvopt.sh

#!/usr/bin/env bash
# Python virtualenvs contain references to base python
# For brew installed python they reference versioned Cellar
# Which breaks even on minor update
# This hacky script rewrites all those references to opt based,
# unversioned ones.
#
# Example usage: fixvenvopt.sh ~/.virtualenvs/jupyter

set -euo pipefail

noversion() {
    # Yup, sed spawned on each invokation. I'm not proud of this either.
    printf "%s" "$1" | sed 's#Cellar/python/[^/]*/#opt/python/#'
}

if [[ "$#" != 1 ]]; then
    echo "Usage: $0 virtualenv_path"
    exit 1
fi

cd "$1"

for f in $(find . -type l); do
  lnk="$(readlink "$f")"
  if [[ $lnk = *Cellar* ]]; then
    rm "$f"
    ln -s "$(noversion $lnk)" "$f"
  fi
done

orig_prefix_v="$(cat lib/python*/orig-prefix.txt)"
# tee is needed to force glob expansion
echo "$(noversion "$orig_prefix_v")" | tee lib/python*/orig-prefix.txt >/dev/null