tools/git-if-needed/python/src/gifn_apply/git.py

# SPDX-FileCopyrightText: StorPool <support@storpool.com>
# SPDX-License-Identifier: BSD-2-Clause
"""Clone a Git repository."""

from __future__ import annotations

import subprocess  # noqa: S404
import typing

from . import defs


if typing.TYPE_CHECKING:
    import pathlib
    from typing import Final


class GitError(defs.GApplyError):
    """An error that occurred during a Git-related operation."""


def repo_clone(cfg: defs.Config, repo: defs.Repo, tempd: pathlib.Path) -> pathlib.Path:
    """Clone a Git repository."""
    loc: Final = cfg.repo_urls.get(repo.origin.upper())
    if loc is None:
        raise GitError(f"Unknown repository origin {repo.origin!r}")
    cfg.log.info(
        "Cloning the %(origin)s %(repo)s repository from %(loc)s",
        {"origin": repo.origin, "repo": repo.repo, "loc": loc.url.geturl()},
    )

    repo_url: Final = loc.url._replace(
        path=loc.url.path + ("" if loc.url.path.endswith("/") else "/") + repo.repo,
    )
    repo_dir: Final = tempd / repo.origin / repo.repo
    if repo_dir.exists() or repo_dir.is_symlink():
        raise GitError(f"Did not expect {repo_dir} to exist")
    repo_dir.parent.mkdir(mode=0o755, exist_ok=True, parents=True)

    cfg.log.debug(
        "About to clone %(repo_url)s into %(repo_dir)s",
        {"repo_url": repo_url.geturl(), "repo_dir": repo_dir},
    )
    try:
        subprocess.run(
            ["git", "clone", repo_url.geturl(), repo.repo, "-b", "master"],  # noqa: S603,S607
            check=True,
            cwd=repo_dir.parent,
        )
    except (OSError, subprocess.CalledProcessError) as err:
        raise GitError(
            f"Could not run `git clone {repo_url.geturl()} {repo.repo}` in {tempd}: {err}",
        ) from err
    if not repo_dir.is_dir():
        raise GitError(f"`git clone` did not create {repo_dir}")

    return repo_dir


def list_change_ids(cfg: defs.Config, repo_dir: pathlib.Path) -> list[str]:
    """Get the Change-Id fields of all the commits reachable from the current head."""
    cfg.log.info("Getting the change IDs in %(repo_dir)s", {"repo_dir": repo_dir})
    try:
        lines = [
            line
            for line in subprocess.check_output(
                ["git", "log", "--pretty=%(trailers:key=Change-Id)", "--reverse"],  # noqa: S607
                cwd=repo_dir,
                encoding="UTF-8",
                shell=False,  # noqa: S603
            ).splitlines()
            if line
        ]
    except (OSError, subprocess.CalledProcessError) as err:
        raise GitError(f"Could not run `git log` for change IDs in {repo_dir}: {err}") from err
    except ValueError as err:
        raise GitError(
            f"Could not decode the output of `git log` in {repo_dir} into UTF-8 change IDs: {err}",
        ) from err

    def parse_line(line: str) -> str:
        """Parse a "Change-Id: Ixxx" line."""
        fields: Final = line.split()
        # The magic value will go away once we can use structural pattern matching
        if (
            len(fields) != 2  # noqa: PLR2004
            or fields[0] != "Change-Id:"
            or not fields[1].startswith("I")
        ):
            raise GitError(f"Unexpected `git log` ouput for change IDs: {line!r}")
        return fields[1]

    return [parse_line(line) for line in lines]