head.py

# This module is part of GitPython and is released under the
# 3-Clause BSD License: https://opensource.org/license/bsd-3-clause/

"""Some ref-based objects.

Note the distinction between the :class:`HEAD` and :class:`Head` classes.
"""

from git.config import GitConfigParser, SectionConstraint
from git.util import join_path
from git.exc import GitCommandError

from .symbolic import SymbolicReference
from .reference import Reference

# typing ---------------------------------------------------

from typing import Any, Sequence, Union, TYPE_CHECKING

from git.types import PathLike, Commit_ish

if TYPE_CHECKING:
    from git.repo import Repo
    from git.objects import Commit
    from git.refs import RemoteReference

# -------------------------------------------------------------------

__all__ = ["HEAD", "Head"]


def strip_quotes(string: str) -> str:
    if string.startswith('"') and string.endswith('"'):
        return string[1:-1]
    return string


class HEAD(SymbolicReference):
    """Special case of a SymbolicReference representing the repository's HEAD
    reference."""

    _HEAD_NAME = "HEAD"
    _ORIG_HEAD_NAME = "ORIG_HEAD"

    __slots__ = ()

    def __init__(self, repo: "Repo", path: PathLike = _HEAD_NAME) -> None:
        if path != self._HEAD_NAME:
            raise ValueError("HEAD instance must point to %r, got %r" % (self._HEAD_NAME, path))
        super().__init__(repo, path)
        self.commit: "Commit"

    def orig_head(self) -> SymbolicReference:
        """
        :return:
            :class:`~git.refs.symbolic.SymbolicReference` pointing at the ORIG_HEAD,
            which is maintained to contain the previous value of HEAD.
        """
        return SymbolicReference(self.repo, self._ORIG_HEAD_NAME)

    def reset(
        self,
        commit: Union[Commit_ish, SymbolicReference, str] = "HEAD",
        index: bool = True,
        working_tree: bool = False,
        paths: Union[PathLike, Sequence[PathLike], None] = None,
        **kwargs: Any,
    ) -> "HEAD":
        """Reset our HEAD to the given commit optionally synchronizing the index and
        working tree. The reference we refer to will be set to commit as well.

        :param commit:
            :class:`~git.objects.commit.Commit`, :class:`~git.refs.reference.Reference`,
            or string identifying a revision we should reset HEAD to.

        :param index:
            If ``True``, the index will be set to match the given commit.
            Otherwise it will not be touched.

        :param working_tree:
            If ``True``, the working tree will be forcefully adjusted to match the given
            commit, possibly overwriting uncommitted changes without warning.
            If `working_tree` is ``True``, `index` must be ``True`` as well.

        :param paths:
            Single path or list of paths relative to the git root directory
            that are to be reset. This allows to partially reset individual files.

        :param kwargs:
            Additional arguments passed to ``git reset``.

        :return:
            self
        """
        mode: Union[str, None]
        mode = "--soft"
        if index:
            mode = "--mixed"

            # Tt appears some git versions declare mixed and paths deprecated.
            # See http://github.com/Byron/GitPython/issues#issue/2.
            if paths:
                mode = None
            # END special case
        # END handle index

        if working_tree:
            mode = "--hard"
            if not index:
                raise ValueError("Cannot reset the working tree if the index is not reset as well")

        # END working tree handling

        try:
            self.repo.git.reset(mode, commit, "--", paths, **kwargs)
        except GitCommandError as e:
            # git nowadays may use 1 as status to indicate there are still unstaged
            # modifications after the reset.
            if e.status != 1:
                raise
        # END handle exception

        return self


class Head(Reference):
    """A Head is a named reference to a :class:`~git.objects.commit.Commit`. Every Head
    instance contains a name and a :class:`~git.objects.commit.Commit` object.

    Examples::

        >>> repo = Repo("/path/to/repo")
        >>> head = repo.heads[0]

        >>> head.name
        'master'

        >>> head.commit
        <git.Commit "1c09f116cbc2cb4100fb6935bb162daa4723f455">

        >>> head.commit.hexsha
        '1c09f116cbc2cb4100fb6935bb162daa4723f455'
    """

    _common_path_default = "refs/heads"
    k_config_remote = "remote"
    k_config_remote_ref = "merge"  # Branch to merge from remote.

    @classmethod
    def delete(cls, repo: "Repo", *heads: "Union[Head, str]", force: bool = False, **kwargs: Any) -> None:
        """Delete the given heads.

        :param force:
            If ``True``, the heads will be deleted even if they are not yet merged into
            the main development stream. Default ``False``.
        """
        flag = "-d"
        if force:
            flag = "-D"
        repo.git.branch(flag, *heads)

    def set_tracking_branch(self, remote_reference: Union["RemoteReference", None]) -> "Head":
        """Configure this branch to track the given remote reference. This will
        alter this branch's configuration accordingly.

        :param remote_reference:
            The remote reference to track or None to untrack any references.

        :return:
            self
        """
        from .remote import RemoteReference

        if remote_reference is not None and not isinstance(remote_reference, RemoteReference):
            raise ValueError("Incorrect parameter type: %r" % remote_reference)
        # END handle type

        with self.config_writer() as writer:
            if remote_reference is None:
                writer.remove_option(self.k_config_remote)
                writer.remove_option(self.k_config_remote_ref)
                if len(writer.options()) == 0:
                    writer.remove_section()
            else:
                writer.set_value(self.k_config_remote, remote_reference.remote_name)
                writer.set_value(
                    self.k_config_remote_ref,
                    Head.to_full_path(remote_reference.remote_head),
                )

        return self

    def tracking_branch(self) -> Union["RemoteReference", None]:
        """
        :return:
            The remote reference we are tracking, or ``None`` if we are not a tracking
            branch.
        """
        from .remote import RemoteReference

        reader = self.config_reader()
        if reader.has_option(self.k_config_remote) and reader.has_option(self.k_config_remote_ref):
            ref = Head(
                self.repo,
                Head.to_full_path(strip_quotes(reader.get_value(self.k_config_remote_ref))),
            )
            remote_refpath = RemoteReference.to_full_path(join_path(reader.get_value(self.k_config_remote), ref.name))
            return RemoteReference(self.repo, remote_refpath)
        # END handle have tracking branch

        # We are not a tracking branch.
        return None

    def rename(self, new_path: PathLike, force: bool = False) -> "Head":
        """Rename self to a new path.

        :param new_path:
            Either a simple name or a path, e.g. ``new_name`` or ``features/new_name``.
            The prefix ``refs/heads`` is implied.

        :param force:
            If ``True``, the rename will succeed even if a head with the target name
            already exists.

        :return:
            self

        :note:
            Respects the ref log, as git commands are used.
        """
        flag = "-m"
        if force:
            flag = "-M"

        self.repo.git.branch(flag, self, new_path)
        self.path = "%s/%s" % (self._common_path_default, new_path)
        return self

    def checkout(self, force: bool = False, **kwargs: Any) -> Union["HEAD", "Head"]:
        """Check out this head by setting the HEAD to this reference, by updating the
        index to reflect the tree we point to and by updating the working tree to
        reflect the latest index.

        The command will fail if changed working tree files would be overwritten.

        :param force:
            If ``True``, changes to the index and the working tree will be discarded.
            If ``False``, :class:`~git.exc.GitCommandError` will be raised in that
            situation.

        :param kwargs:
            Additional keyword arguments to be passed to git checkout, e.g.
            ``b="new_branch"`` to create a new branch at the given spot.

        :return:
            The active branch after the checkout operation, usually self unless a new
            branch has been created.
            If there is no active branch, as the HEAD is now detached, the HEAD
            reference will be returned instead.

        :note:
            By default it is only allowed to checkout heads - everything else will leave
            the HEAD detached which is allowed and possible, but remains a special state
            that some tools might not be able to handle.
        """
        kwargs["f"] = force
        if kwargs["f"] is False:
            kwargs.pop("f")

        self.repo.git.checkout(self, **kwargs)
        if self.repo.head.is_detached:
            return self.repo.head
        else:
            return self.repo.active_branch

    # { Configuration
    def _config_parser(self, read_only: bool) -> SectionConstraint[GitConfigParser]:
        if read_only:
            parser = self.repo.config_reader()
        else:
            parser = self.repo.config_writer()
        # END handle parser instance

        return SectionConstraint(parser, 'branch "%s"' % self.name)

    def config_reader(self) -> SectionConstraint[GitConfigParser]:
        """
        :return:
            A configuration parser instance constrained to only read this instance's
            values.
        """
        return self._config_parser(read_only=True)

    def config_writer(self) -> SectionConstraint[GitConfigParser]:
        """
        :return:
            A configuration writer instance with read-and write access to options of
            this head.
        """
        return self._config_parser(read_only=False)

    # } END configuration