Git refresh

git-refresh.sh

#!/usr/bin/env bash

set -o errexit

## git refresh
#
# Update all git remotes
# Update local main or master branch from the remote
# Delete local branches tracking remotely-deleted branches
# Delete local branches that have been merged
# Print local branches that are outdated

function checkbranch {
  name="$1"
  status="$(git branch -l "$name" --format '%(refname:short)')"
  if [[ -z "$status" ]]; then
    return 1
  else
    return 0
  fi
}

if checkbranch main; then
  MAINBRANCH=main
elif checkbranch master; then
  MAINBRANCH=master
else
  # If we have an "upstream" branch, then our git clone is probably a fork - we should use their default branch and not origin
  if git remote | grep -q upstream; then
    remote=upstream
  else
    remote=origin
  fi

  # Attempt to detect the branch github declares as the main one, if possible
  remote_url=$(git remote get-url $remote)
  if [[ $remote_url == git@github.com* ]]; then
    # This git repo is tracking github
    # Extract the username and repository name from the URL
    username=$(echo $remote_url | cut -d: -f2 | cut -d/ -f1)
    repository=$(echo $remote_url | cut -d/ -f2 | cut -d. -f1)
    echo "main branch not detected - attempting to query from $username/$repository on github"

    # Try to find github auth in case the repo is private
    if [[ -n $GITHUB_TOKEN ]]; then
      token="$GITHUB_TOKEN"
    elif [[ -n $GH_TOKEN ]]; then
      token="$GH_TOKEN"
    fi
    if [[ -n $token ]]; then
      auth_args="-H \"Authorization: Bearer $token\""
    else
      auth_args=""
    fi

    # Ask github what the main branch is, using auth if we found it
    MAINBRANCH=$(curl -s $auth_args https://api.github.com/repos/$username/$repository | jq -r .default_branch)
    echo "Detected $MAINBRANCH as the default branch on github"
  fi
fi

if [[ $1 == "-m" ]]; then
  if [[ -n $2 ]]; then
    MAINBRANCH="$2"
  fi
  if [[ -z $MAINBRANCH ]]; then
    echo "Cannot change branch to main: main branch not detected. Run \`git refresh -m mainbranchname\` to change branches"
    exit 1
  fi
  git checkout $MAINBRANCH
  shift
elif [[ -n $1 ]]; then
  MAINBRANCH="$1"
fi

git remote update --prune || true
if [[ -n $MAINBRANCH ]]; then
  if [[ "$(git branch | sed -n '/\* /s///p')" == "$MAINBRANCH" ]]; then
    # On master, fast forward.
    git merge --ff-only origin/$MAINBRANCH
  else
    # force-set local master to point at origin/master's commit
    # Do this to avoid changing the reflog, or invalidating compiler cache etc
    git branch -f $MAINBRANCH origin/$MAINBRANCH
  fi
  # Delete local branches that have been merged to main
  git branch --merged origin/$MAINBRANCH | grep -v $MAINBRANCH | grep -vF '*' | xargs git branch -d
else
  echo "main branch not detected. Run \`git refresh branchname\` to treat \`branchname\` as a main branch"
fi
echo "Outdated"

# Delete local branches which are tracking a remote branch which is gone (eg squash+merge on github)
git branch --format '%(upstream:track,nobracket)%09%(refname:short)' | awk -F "\t" '{ if($1 = /gone/) { print $2 } }' | xargs git branch -D

# List local branches not merged to master
if [[ -n $MAINBRANCH ]]; then
  git branch --no-contains origin/$MAINBRANCH --sort=-committerdate -vv
fi