Add release task

Signed-off-by: Bernát Gábor <bgabor8@bloomberg.net>

1 files changed, 72 insertions, 0 deletions

diff --git a/tasks/release.py b/tasks/release.py
new file mode 100644
index 00000000..5e739109
--- /dev/null
+++ b/tasks/release.py
@@ -0,0 +1,72 @@
+"""Handles creating a release PR"""
+from pathlib import Path
+from subprocess import check_call
+from typing import Tuple
+
+from git import Commit, Head, Remote, Repo, TagReference
+from packaging.version import Version
+
+ROOT_SRC_DIR = Path(__file__).parents[1]
+
+
+def main(version_str: str) -> None:
+    version = Version(version_str)
+    repo = Repo(str(ROOT_SRC_DIR))
+
+    if repo.is_dirty():
+        raise RuntimeError("Current repository is dirty. Please commit any changes and try again.")
+    upstream, release_branch = create_release_branch(repo, version)
+    release_commit = release_changelog(repo, version)
+    tag = tag_release_commit(release_commit, repo, version)
+    print("push release commit")
+    repo.git.push(upstream.name, release_branch)
+    print("push release tag")
+    repo.git.push(upstream.name, tag)
+    print("All done! ✨ 🍰 ✨")
+
+
+def create_release_branch(repo: Repo, version: Version) -> Tuple[Remote, Head]:
+    print("create release branch from upstream rewrite")
+    upstream = get_upstream(repo)
+    upstream.fetch()
+    branch_name = f"release-{version}"
+    release_branch = repo.create_head(branch_name, upstream.refs.rewrite, force=True)
+    upstream.push(refspec=f"{branch_name}:{branch_name}", force=True)
+    release_branch.set_tracking_branch(repo.refs[f"{upstream.name}/{branch_name}"])
+    release_branch.checkout()
+    return upstream, release_branch
+
+
+def get_upstream(repo: Repo) -> Remote:
+    for remote in repo.remotes:
+        for url in remote.urls:
+            if url.endswith("tox-dev/tox.git"):
+                return remote
+    raise RuntimeError("could not find tox-dev/tox.git remote")
+
+
+def release_changelog(repo: Repo, version: Version) -> Commit:
+    print("generate release commit")
+    check_call(["towncrier", "--yes", "--version", version.public], cwd=str(ROOT_SRC_DIR))
+    release_commit = repo.index.commit(f"release {version}")
+    return release_commit
+
+
+def tag_release_commit(release_commit, repo, version) -> TagReference:
+    print("tag release commit")
+    existing_tags = [x.name for x in repo.tags]
+    if version in existing_tags:
+        print(f"delete existing tag {version}")
+        repo.delete_tag(version)
+    print(f"create tag {version}")
+    tag = repo.create_tag(version, ref=release_commit, force=True)
+    return tag
+
+
+if __name__ == "__main__":
+    import argparse
+
+    parser = argparse.ArgumentParser(prog="release")
+    parser.add_argument("--version", required=True)
+    options = parser.parse_args()
+    main(options.version)