git-update

README.rst

git update

Do the right thing when updating branches

Author:	joepvd
Date:	2024-12-14
Copyright:	GPLv2
Version:	0.2
Manual section:	1

SYNOPSIS

git update

DESCRIPTION

For automatically rebasing current branch to freshly fetched origin branch, and rebase local branches with upstream changes. Optionally, a configuration file can be used for a list of read-only checkouts for relevant branches.

If you're daring: `sh git config --global alias.pull git-update `

Features (any repo)

• fetches upstream origin
• ensures the local main branch is current with the upstream main branch
• ensures the currently checked out branch gets the changes from its originating branch

Features configured repo

In addition to the general features, it is possible to configure read only checkouts in a different directory. Take this example:

It: * ensures all openshift-$VERSION branches are up to date with their origin

counterpart

• ensures the read-only worktree checkouts under ~/ocp-ro/$VERSION are up to date with origin.
• can run git update in read only worktree, and updates the real repository with all relevant branches, and all the read only worktree checkouts.

Example config is in /usr/share/git-update/git-update.yaml. Copy to ~/.config/git-update.yaml and edit.

This makes use of the [worktree](https://git-scm.com/docs/git-worktree) feature of git. The result is a directory ~/ocp-ro, where for each relevant version, a complete and current checkout of the origin state of that version is.

The purpose of these checkouts is to easily query and compare facts between branches.

These checkouts are headless, as the local knowledge of the remote state is checked out. Files and directories in the worktree checkouts are set to be readonly, to ensure the character of "upstream truth" is maintained.

git-update

#!/usr/bin/env bash

set -euo pipefail
shopt -s extglob

main() {
  repo_path="$(realpath "$(dirname "$(git rev-parse --git-common-dir)")")"
  reponame="$(basename "$repo_path")"
  current_branch="$(git rev-parse --abbrev-ref HEAD)"
  main_branch="$(get_main_branch)"

  cd "$repo_path"

  fetch_origin

  update_branch "$main_branch" "origin/$main_branch"

  config="$(get_config "$reponame")"

  if [[ -n "$config" ]]; then
    update_worktrees
  fi
  # Rebase current branch on most recent originating branch
  git checkout --quiet "$current_branch"
  if [[ "$current_branch" != "$main_branch" ]]; then
    o="$(originating_branch)"
    [[ -n "$o" ]] && update_branch "$current_branch" "$o"
  fi
}

originating_branch() {
  local i res
  i=0
  res=""

  while [[ -z "$res" ]] && ((i < 100 )); do 
    res=$(git branch -r --list 'origin/*' --contains "HEAD~$i" | awk '{print $1; exit}')
    i=$((i+1))
  done

  echo "$res"
}

get_main_branch() {
  if git rev-parse --verify origin/main >/dev/null 2>&1; then
    echo main
  elif git rev-parse --verify origin/master >/dev/null 2>&1; then
    echo master
  else
    echo "No main/master branch detected">/dev/stderr
    exit 1
  fi
}

fetch_origin() {
  git diff --quiet || {
    echo branch not clean. exiting >/dev/stderr
    exit 1
  }
  
  echo "Fetching origin" >/dev/stderr
  git fetch --quiet origin
}

update_branch() {
  local local_branch remote_branch local_head remote_head
  local_branch="$1"
  remote_branch="$2"
  git checkout --quiet "$local_branch"
  local_head="$(git rev-parse --short HEAD)"
  remote_head="$(git log --pretty=format:%h -n 1 "$remote_branch")"
  if [[ "$local_head" == "$remote_head" ]]; then
    echo "No updates for $local_branch" >/dev/stderr
  else
    echo "rebasing branch $remote_branch onto $local_branch: $local_head..$remote_head" >/dev/stderr
    git rebase --quiet "$remote_branch"
  fi
}


get_config() {
  local reponame="$1"
  # shellcheck disable=SC2016
  yq --arg name "$reponame" '
    .[]
    | select((.repo | split("/").[-1] ) == $name )
  ' ~/.config/git-update.yaml || true
}

update_worktrees() {
  worktree_dir="$(jq -r .worktree_dir <<<"$config")"
  eval worktree_dir="$worktree_dir"  # expand ~
  mkdir -p "$worktree_dir"
  shopt -s nullglob
  chmod --recursive +w "$worktree_dir"/* 2>/dev/null || true
  trap 'chmod --recursive -w "$worktree_dir"/*' EXIT
  while read -r branch dir; do
    update_branch "$branch" "origin/$branch"
    ( 
      echo "Updating worktree $worktree_dir/$dir" >/dev/stderr
      if [[ -d "$worktree_dir/$dir" ]]; then
        cd "$worktree_dir/$dir"
        git checkout --quiet "origin/$branch"
      else
        git worktree add "$worktree_dir/$dir" "origin/$branch"
      fi
    )
  done < <(
    jq -r '.checkouts[] | .branch + " " + .dir' <<<"$config"
  )
}

main

git-update.spec.rpkg

Name: {{{ git_dir_name }}}
Version: 0.2
Release: 0%{?dist}
Summary: Display data in pretty table in terminal

License: GPLv2
URL: https://github.com/joepvd/git-update
VCS: {{{ git_dir_vcs }}}
Source: {{{ git_dir_pack }}}

BuildRequires: python3-docutils
Requires: git
Requires: jq
Requires: yq

%global debug_package %{nil}

%description
Do the right thing when updating branches

%prep
{{{ git_dir_setup_macro }}}

%build
rst2man README.rst | gzip >git-update.1.gz

%install
mkdir -p %{buildroot}/usr/bin
install -m 755 git-update %{buildroot}/usr/bin/git-update

mkdir -p %{buildroot}/usr/share/man/man1
install -m 644 git-update.1.gz %{buildroot}/usr/share/man/man1/git-update.1.gz

mkdir -p %{buildroot}/usr/share/git-update
install -m 644 git-update.yaml %{buildroot}/usr/share/git-update/git-update.yaml

%files
/usr/bin/git-update
/usr/share/man/man1/git-update.1.gz
/usr/share/git-update/git-update.yaml

%license
%doc

%changelog
{{{ git_dir_changelog }}}

git-update.yaml

- repo: ~/src/github.com/openshift-eng/ocp-build-data
  worktree_dir: ~/ocp-ro
  checkouts:
  - branch: openshift-3.11
    dir: "3.11"
  - branch: openshift-4.12
    dir: "4.12"
  - branch: openshift-4.13
    dir: "4.13"
  - branch: openshift-4.14
    dir: "4.14"
  - branch: openshift-4.15
    dir: "4.15"
  - branch: openshift-4.16
    dir: "4.16"
  - branch: openshift-4.17
    dir: "4.17"
  - branch: openshift-4.18
    dir: "4.18"
  - branch: openshift-4.19
    dir: "4.19"