Add license adder script

tools/add_license.py

@@ -0,0 +1,141 @@
+"""
+Add a LICENSE file to the specified repos.
+
+Note intended to be reused: just kept for posterity.
+"""
+
+import argparse
+import pathlib
+import shutil
+import subprocess
+import textwrap
+import webbrowser
+from collections.abc import Iterable, Sequence
+
+FEATURE_BRANCH = "add-license"
+COMMIT_MESSAGE = "feat: add license"
+NEW_PR_LINK = r"https://github.com/billwallis/{repository}/pull/new/{branch}"
+# ruff: noqa: E101
+EXPECTED_GIT_STATUS = textwrap.dedent(
+    """\
+    On branch add-license
+    Untracked files:
+      (use "git add <file>..." to include in what will be committed)
+    	LICENSE
+
+    nothing added to commit but untracked files present (use "git add" to track)
+    """
+).rstrip()
+HERE = pathlib.Path(__file__).parent
+assert HERE.parent.name == "python-template"  # noqa: S101
+LICENSE_FILE = HERE.parent / "LICENSE"
+
+
+def git(
+    args: Iterable[str],
+    git_dir: pathlib.Path,
+) -> str:
+    proc = subprocess.run(
+        args=("git", "-C", git_dir, *args),
+        check=False,  # DON'T raise an exception on non-zero return codes
+        capture_output=True,
+    )
+
+    assert isinstance(proc.stdout, bytes)  # noqa: S101
+    assert isinstance(proc.stderr, bytes)  # noqa: S101
+
+    out = proc.stdout.decode().rstrip()
+    err = proc.stderr.decode().rstrip()
+
+    if proc.returncode != 0:
+        raise RuntimeError(f"exit code {proc.returncode}:\n{err}")
+
+    return out
+
+
+def _checkout_branch(
+    repository: pathlib.Path,
+    branch: str,
+    create: bool = False,
+) -> None:
+    args = ("-c", branch) if create else (branch,)
+    git(("switch", *args), git_dir=repository)
+
+
+def _delete_branch(repository: pathlib.Path, branch: str) -> None:
+    git(("branch", "--delete", branch), git_dir=repository)
+
+
+def _push_current_branch(repository: pathlib.Path) -> None:
+    git(("push",), git_dir=repository)
+
+
+def _add_license_file(repository: pathlib.Path) -> None:
+    shutil.copy(
+        src=LICENSE_FILE,
+        dst=repository / LICENSE_FILE.name,
+    )
+    out = git(("status",), git_dir=repository)
+
+    assert out == EXPECTED_GIT_STATUS, f"`{out}`\n!=\n`{EXPECTED_GIT_STATUS}`"  # noqa: S101
+
+
+def _commit_license_file(repository: pathlib.Path) -> None:
+    git(("add", LICENSE_FILE.name), git_dir=repository)
+    git(("commit", "-m", COMMIT_MESSAGE), git_dir=repository)
+
+
+def _open_pull_request(repository: pathlib.Path) -> None:
+    webbrowser.open(
+        NEW_PR_LINK.format(
+            repository=repository.name,
+            branch=FEATURE_BRANCH,
+        )
+    )
+
+
+def add_license(repository: pathlib.Path) -> int:
+    print(f"Adding license to '{repository}'")
+    if not repository.exists():
+        print(f"\tRepo does not exist at {repository}")
+        return 1
+
+    # gross and lazy massive try block
+    try:
+        print("\tCheckout feature branch")
+        _checkout_branch(repository, FEATURE_BRANCH, create=True)
+        print("\tAdd licence file")
+        _add_license_file(repository)
+        print("\tCommit licence file")
+        _commit_license_file(repository)
+        print("\tPush changes")
+        _push_current_branch(repository)
+        print("\tOpen pull request")
+        _open_pull_request(repository)
+        print("\tCheckout main branch")
+        _checkout_branch(repository, "main")
+        print("\tDelete feature branch")
+        _delete_branch(repository, FEATURE_BRANCH)
+        return 0
+    except RuntimeError as e:
+        print(e)
+        return 1
+
+
+def main(argv: Sequence[str] | None = None) -> int:
+    """
+    Parse the arguments and run the hook.
+    """
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument("repositories", nargs="*")
+    args = parser.parse_args(argv)
+
+    outcome = 0
+    for repository in args.repositories:
+        outcome |= add_license(pathlib.Path(repository).resolve())
+    return outcome
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())  # pragma: no cover