Initial commit

.gitattributes

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+# Default behavior
+# ============
+*           text=auto
+
+# Source files
+# ============
+*manage.py  text diff=python eol=lf
+*.py        text diff=python
+*.pxd       text diff=python
+*.py3       text diff=python
+*.pyw       text diff=python
+*.pyx       text diff=python
+*.pyz       text diff=python
+*.pyi       text diff=python
+
+# Plain text
+# ============
+*.js        text diff=js
+*.css       text diff=css
+*.html      text diff=html
+*.md        text diff=markdown
+*.json      text diff=json eol=lf
+*.toml      text diff=toml eol=lf
+*.yml       text diff=yaml eol=lf
+*.yaml      text diff=yaml eol=lf
+
+# Archives
+# ============
+*.7z        filter=lfs diff=lfs merge=lfs -text
+*.br        filter=lfs diff=lfs merge=lfs -text
+*.gz        filter=lfs diff=lfs merge=lfs -text
+*.tar       filter=lfs diff=lfs merge=lfs -text
+*.zip       filter=lfs diff=lfs merge=lfs -text
+
+# Binary files
+# ============
+*.db        binary
+*.p         binary
+*.pkl       binary
+*.pickle    binary
+*.pyc       binary export-ignore
+*.pyo       binary export-ignore
+*.pyd       binary
+*.png       binary
+*.jpg       binary
+
+# Unix specific
+# ============
+*.sh        text eol=lf
+*.bash      text eol=lf
+*.fish      text eol=lf
+
+# Windows specific
+# ============
+*.cmd       text eol=crlf
+*.bat       text eol=crlf
+*.ps1       text eol=crlf

.github/workflows/fast-forward.yml

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+name: Fast-forward
+
+on:
+  issue_comment:
+    types:
+      - created
+      - edited
+
+jobs:
+  fast-forward:
+
+    name: Fast-forward
+    runs-on: ubuntu-latest
+
+    permissions:
+      contents: write  # Allows merging the PR.
+      pull-requests: write  # Writing comments on PRs.
+      issues: write  # Also required for posting comments on PRs.
+
+    # Only run if the comment is one of the defined keywords.
+    if: >-
+      ${{
+        github.event.issue.pull_request
+        && contains(fromJSON('["/fast-forward", "/ff"]'), github.event.comment.body)
+      }}
+
+    steps:
+      - name: Fast-forward
+        uses: MrThearMan/prff@main

.github/workflows/test.yml

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+name: Test
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  test:
+
+    name: Test
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+
+      - run: pip install pytest
+      - run: pytest -s -vv --log-cli-level=DEBUG --disable-warnings .

LICENSE

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+MIT License
+
+Copyright (c) Matti Lamppu
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# Fast-forward merge for pull requests
+
+This action adds the ability to fast-forward merge pull requests by
+commenting a predefined comment on the pull request.
+
+Example:
+
+```yaml
+name: Fast-forward
+
+on:
+  issue_comment:
+    types:
+      - created
+      - edited
+
+jobs:
+  fast-forward:
+
+    name: Fast-forward
+    runs-on: ubuntu-latest
+
+    permissions:
+      contents: write  # Allows merging the PR.
+      pull-requests: write  # Writing comments on PRs.
+      issues: write  # Also required for posting comments on PRs.
+
+    # Only run if the comment is one of the defined keywords.
+    if: >-
+      ${{
+        github.event.issue.pull_request
+        && contains(fromJSON('["/fast-forward", "/ff"]'), github.event.comment.body)
+      }}
+
+    steps:
+      - name: Fast-forward
+        uses: MrThearMan/prff@v1
+```
+
+With this, by commenting either `/ff` or `/fast-forward` on the pull request, the action
+will run to check if the fast forward merge is possible, and that the commenter has
+the requird permissions to make that merge, and then make the merge if those checks pass.
+
+If this operation is unsuccessful, a comment will be added to the pull request
+with the error. A detailed report is also written to the actions summary.

action.yml

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+name: Fast-forward
+description: Fast-forward merge a pull request.
+
+inputs:
+  github_token:
+    description: GitHub Actions token.
+    default: ${{ github.token }}
+
+runs:
+  using: "composite"
+  steps:
+    - uses: actions/setup-python@v5
+      with:
+        python-version: '3.12'
+
+    - name: Fast-forward
+      id: fast-forward
+      env:
+        GITHUB_TOKEN: ${{ inputs.github_token }}
+        PYTHONUNBUFFERED: "1"
+        PYTHONDONTWRITEBYTECODE: "1"
+        PYTHONFAULTHANDLER: "1"
+        PYTHONENCODING: "utf-8"
+      run: python ${{ github.action_path }}/main.py
+      shell: bash

main.py

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+#!/usr/bin/env python
+
+from prff.exception import PullRequestFastForwardError
+from prff.fast_forward import fast_forward_pull_request
+from prff.github_actions import load_event_data, write_job_summary
+from prff.github_api import add_rocket_reaction
+from prff.logging import logger
+
+if __name__ == "__main__":
+    exit_code: int = 0
+
+    try:
+        event_data = load_event_data()
+        fast_forward_pull_request(
+            pull_request_url=event_data.pull_request_url,
+            permissions_url=event_data.permissions_url,
+        )
+
+    except PullRequestFastForwardError as error:
+        logger.error(error)
+        exit_code = 1
+
+    except Exception as error:  # noqa: BLE001
+        logger.exception("An unexpected error occurred", exc_info=error)
+        exit_code = 1
+
+    else:
+        add_rocket_reaction(reactions_url=event_data.reactions_url)
+
+    finally:
+        write_job_summary()
+
+    raise SystemExit(exit_code)

prff/command.py

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+from __future__ import annotations
+
+import subprocess
+from dataclasses import dataclass
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from pathlib import Path
+
+__all__ = [
+    "run_command",
+]
+
+
+@dataclass
+class CommandResult:
+    out: str | None
+    err: str | None
+    exit_code: int
+
+
+def run_command(command: str, *, directory: Path | str | None = None) -> CommandResult:
+    """
+    Run a command in the given directory using subprocess.
+
+    :param command: The command string to run.
+    :param directory: The directory to run the command in.
+    """
+    process = subprocess.Popen(command.split(" "), stdout=subprocess.PIPE, stderr=subprocess.PIPE, cwd=directory)
+    stdout, stderr = process.communicate()
+
+    error = stderr.decode().strip() or None
+    result = stdout.decode().strip() if not error else None
+
+    return CommandResult(out=result, err=error, exit_code=process.returncode)

prff/constants.py

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+import os
+
+REPO_PATH = "./clone"
+GITHUB_TOKEN = os.environ["GITHUB_TOKEN"]
+GITHUB_ACTOR = os.environ["GITHUB_ACTOR"]
+SUMMARY_FILE = os.environ["GITHUB_STEP_SUMMARY"]
+EVENT_PATH = os.environ["GITHUB_EVENT_PATH"]

prff/exception.py

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+__all__ = [
+    "PullRequestFastForwardError",
+]
+
+
+class PullRequestFastForwardError(Exception):
+    """Base class for exceptions in this library."""

prff/fast_forward.py

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+from __future__ import annotations
+
+from prff.git import clone_repo_at_branch, create_branch, fetch_commit, push_branch_to_commit, validate_fast_forward
+from prff.github_api import fetch_user_permissions, post_error_comment, validate_push_permissions
+from prff.pull_request import PullRequestData
+
+__all__ = [
+    "fast_forward_pull_request",
+]
+
+
+def fast_forward_pull_request(*, pull_request_url: str, permissions_url: str) -> None:
+    pull_request = PullRequestData.from_github(url=pull_request_url)
+
+    try:
+        permissions = fetch_user_permissions(url=permissions_url)
+        validate_push_permissions(permissions=permissions)
+
+        clone_repo_at_branch(repo_url=pull_request.base_clone_url, branch_name=pull_request.base_branch_name)
+        fetch_commit(repo_url=pull_request.pr_clone_url, commit_sha=pull_request.pr_head_sha)
+        create_branch(branch_name=pull_request.pr_branch_name, commit_sha=pull_request.pr_head_sha)
+        pull_request.fix_base_sha()
+
+        validate_fast_forward(base_sha=pull_request.base_head_sha, head_sha=pull_request.pr_head_sha)
+        push_branch_to_commit(branch_name=pull_request.base_branch_name, commit_sha=pull_request.pr_head_sha)
+
+        # TODO: Trigger another workflow after merging:
+        #  https://docs.github.com/en/actions/writing-workflows/choosing-when-your-workflow-runs/events-that-trigger-workflows#repository_dispatch
+
+    except Exception as error:
+        post_error_comment(error=str(error), comments_url=pull_request.comments_url)
+        raise