feat: initial commit

Signed-off-by: Stephan Linz <linz@li-pro.net>

Dockerfile

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+FROM alpine
+
+LABEL "repository"="http://github.com/tiacsys/git-rebase"
+LABEL "homepage"="http://github.com/tiacsys/git-rebase"
+LABEL "maintainer"="TiaC Systems <info@tiac-systems.net>"
+
+RUN apk add --no-cache git openssh-client && \
+  echo "StrictHostKeyChecking no" >> /etc/ssh/ssh_config
+
+ADD *.sh /
+
+ENTRYPOINT ["/entrypoint.sh"]

README.md

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+# Git Rebase
+
+A GitHub Action for branch rebasing in independent repository using **force push**.
+
+## Features
+
+- Rebase branches on a GitHub repository
+- Rebase branches on a remote repository
+- GitHub action can be triggered on a timer or on push or manually
+
+## Usage
+
+> Always make a full backup of your repo (`git clone --mirror`) before using this action.
+
+### GitHub Actions
+
+```yml
+# .github/workflows/git-rebase.yml
+
+on: push
+jobs:
+  git-rebase:
+    runs-on: ubuntu-latest
+    steps:
+      - name: git-rebase
+        uses: tiacsys/git-rebase@v3
+        with:
+          repo: "org/repository"
+          source_branch: "next"
+          destination_branch: "main"
+          ssh_private_key: ${{ secrets.SSH_PRIVATE_KEY }} # optional
+```
+
+##### Using shorthand
+
+You can use GitHub repo shorthand like `username/repository`.
+
+##### Using ssh
+
+> The `ssh_private_key` must be supplied if using ssh clone urls.
+
+```yml
+repo: "git@github.com:username/repository.git"
+```
+or
+```yml
+repo: "git@gitlab.com:username/repository.git"
+```
+
+##### Using https
+
+> The `ssh_private_key` can be omitted if using authenticated https urls.
+
+```yml
+repo: "https://username:personal_access_token@github.com/username/repository.git"
+```
+
+#### Set up deploy keys
+
+> You only need to set up deploy keys if repository is private and ssh clone url is used.
+
+- Generate ssh key for the repository, leave passphrase empty (note that GitHub deploy keys must be unique for a repository)
+
+```sh
+$ ssh-keygen -t rsa -b 4096 -C "your_email@example.com"
+```
+
+- In GitHub, either:
+
+  - add the unique public keys (`key_name.pub`) to _Repo Settings > Deploy keys_ for each repository respectively and allow write access for the destination repository
+
+  or
+
+  - add the single public key (`key_name.pub`) to _Personal Settings > SSH keys_
+
+- Add the private key(s) to _Repo > Settings > Secrets_ for the repository containing the action (`SSH_PRIVATE_KEY`)
+
+### Docker
+
+```sh
+$ docker run --rm -e "SSH_PRIVATE_KEY=$(cat ~/.ssh/id_rsa)" $(docker build -q .) \
+  $SOURCE_REPO $SOURCE_BRANCH $DESTINATION_REPO $DESTINATION_BRANCH
+```
+
+## Author
+
+[TiaC Systems](https://tiac-systems.net/) _info@tiac-systems.net_
+
+## License
+
+[MIT](LICENSE)

action.yml

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+name: Git Rebase Action
+author: TiaC Systems <info@tiac-systems.net>
+description: 🔝  Rebase branch on independent repository
+branding:
+  icon: 'git-pull-request'
+  color: 'gray-dark'
+inputs:
+  repo:
+    description: GitHub repo slug or full url
+    required: true
+  source_branch:
+    description: Branch name to rebase from
+    required: true
+  destination_branch:
+    description: Branch name to rebase to
+    required: true
+  ssh_private_key:
+    description: SSH key used to authenticate with ssh urls provided (optional if public or https url with authentication)
+    required: false
+runs:
+  using: 'docker'
+  image: 'Dockerfile'
+  env:
+    SSH_PRIVATE_KEY: ${{ inputs.ssh_private_key }}
+  args:
+    - ${{ inputs.repo }}
+    - ${{ inputs.source_branch }}
+    - ${{ inputs.destination_branch }}

entrypoint.sh

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+#!/bin/sh
+
+set -e
+
+if [[ -n "$SSH_PRIVATE_KEY" ]]; then
+  mkdir -p /root/.ssh
+  echo "$SSH_PRIVATE_KEY" | sed 's/\\n/\n/g' >/root/.ssh/id_rsa
+  chmod 600 /root/.ssh/id_rsa
+fi
+
+mkdir -p ~/.ssh
+cp /root/.ssh/* ~/.ssh/ 2>/dev/null || true
+
+sh -c "/git-rebase.sh $*"

git-rebase.sh

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+#!/bin/sh
+
+set -e
+
+REPO=$1
+SOURCE_BRANCH=$2
+DESTINATION_BRANCH=$3
+
+if ! echo ${REPO} | grep -Eq ':|@|\.git\/?$'; then
+  if [[ -n "${SSH_PRIVATE_KEY}" || -n "${SOURCE_SSH_PRIVATE_KEY}" ]]; then
+    REPO="git@github.com:${REPO}.git"
+    GIT_SSH_COMMAND="ssh -v"
+  else
+    REPO="https://github.com/${REPO}.git"
+  fi
+fi
+
+echo "SOURCE=${REPO}:${SOURCE_BRANCH}"
+echo "DESTINATION=${REPO}:${DESTINATION_BRANCH}"
+
+git clone "${REPO}" /root/repo --origin remote-repo && cd /root/repo
+
+# Pull all branches references down locally so subsequent commands can see them
+git fetch remote-repo '+refs/heads/*:refs/heads/*' --update-head-ok
+
+# Print out all branches
+git --no-pager branch -a -vv
+
+git config --local user.name "$(git log -n 1 --pretty=format:%cn ${SOURCE_BRANCH})"
+git config --local user.email "$(git log -n 1 --pretty=format:%ce ${SOURCE_BRANCH})"
+
+git rebase --onto "${DESTINATION_BRANCH}" "${DESTINATION_BRANCH}" "${SOURCE_BRANCH}"
+git push remote-repo HEAD:"${SOURCE_BRANCH}" -f