comparison mercurial/copies.py @ 46563:c19c662097e1

copies: detect case when a merge decision overwrite previous data

We now detect and record when a merge case required special logic (eg: thing
that append during the merge, ambiguity leading to picking p1 data, etc) and we
explicitly mark the result as superseding the previous data.

This fixes the family of test we previously added.

Differential Revision: https://phab.mercurial-scm.org/D9613

46562:c692384bb559

                    # This is an arbitrary choice made anew when implementing
                    # changeset based copies. It was made without regards with
                    # potential filelog related behavior.
                    assert parent == 2
                    current_copies = _merge_copies_dict(
                        newcopies, current_copies, isancestor, changes
                    )
            all_copies[current_rev] = current_copies

        # filter out internal details and return a {dest: source mapping}
        final_copies = {}

PICK_MINOR = 0
PICK_MAJOR = 1
PICK_EITHER = 2


def _merge_copies_dict(minor, major, isancestor, changes):
    """merge two copies-mapping together, minor and major

    In case of conflict, value from "major" will be picked.

    - `isancestors(low_rev, high_rev)`: callable return True if `low_rev` is an

    for dest, value in major.items():
        other = minor.get(dest)
        if other is None:
            minor[dest] = value
        else:
            pick = _compare_values(changes, isancestor, dest, other, value)
            if pick == PICK_MAJOR:
                minor[dest] = value
    return minor


def _compare_values(changes, isancestor, dest, minor, major):
    """compare two value within a _merge_copies_dict loop iteration

    return pick

    - pick is one of PICK_MINOR, PICK_MAJOR or PICK_EITHER
    """
    major_tt, major_value = major
    minor_tt, minor_value = minor

    if major_tt == minor_tt:
        # if it comes from the same revision it must be the same value
        assert major_value == minor_value
        return PICK_EITHER
    elif (
        changes is not None
        and minor_value is not None
        and major_value is None
        and dest in changes.salvaged
    ):
        # In this case, a deletion was reverted, the "alive" value overwrite
        # the deleted one.
        return PICK_MINOR
    elif (
        changes is not None
        and major_value is not None
        and minor_value is None
        and dest in changes.salvaged
    ):
        # In this case, a deletion was reverted, the "alive" value overwrite
        # the deleted one.
        return PICK_MAJOR
    elif isancestor(minor_tt, major_tt):
        if changes is not None and dest in changes.merged:
            # change to dest happened on the branch without copy-source change,
            # so both source are valid and "major" wins.
            return PICK_MAJOR
        else:
            return PICK_MAJOR
    elif isancestor(major_tt, minor_tt):
        if changes is not None and dest in changes.merged:
            # change to dest happened on the branch without copy-source change,
            # so both source are valid and "major" wins.
            return PICK_MAJOR
        else:
            return PICK_MINOR
    elif minor_value is None:
        # in case of conflict, the "alive" side wins.
        return PICK_MAJOR
    elif major_value is None:
        # in case of conflict, the "alive" side wins.
        return PICK_MINOR
    else:
        # in case of conflict where both side are alive, major wins.
        return PICK_MAJOR


def _revinfo_getter_extra(repo):
    """return a function that return multiple data given a <rev>"i

46563:c19c662097e1

                    # This is an arbitrary choice made anew when implementing
                    # changeset based copies. It was made without regards with
                    # potential filelog related behavior.
                    assert parent == 2
                    current_copies = _merge_copies_dict(
                        newcopies,
                        current_copies,
                        isancestor,
                        changes,
                        current_rev,
                    )
            all_copies[current_rev] = current_copies

        # filter out internal details and return a {dest: source mapping}
        final_copies = {}

PICK_MINOR = 0
PICK_MAJOR = 1
PICK_EITHER = 2


def _merge_copies_dict(minor, major, isancestor, changes, current_merge):
    """merge two copies-mapping together, minor and major

    In case of conflict, value from "major" will be picked.

    - `isancestors(low_rev, high_rev)`: callable return True if `low_rev` is an

    for dest, value in major.items():
        other = minor.get(dest)
        if other is None:
            minor[dest] = value
        else:
            pick, overwrite = _compare_values(
                changes, isancestor, dest, other, value
            )
            if overwrite:
                if pick == PICK_MAJOR:
                    minor[dest] = (current_merge, value[1])
                else:
                    minor[dest] = (current_merge, other[1])
            elif pick == PICK_MAJOR:
                minor[dest] = value
    return minor


def _compare_values(changes, isancestor, dest, minor, major):
    """compare two value within a _merge_copies_dict loop iteration

    return (pick, overwrite).

    - pick is one of PICK_MINOR, PICK_MAJOR or PICK_EITHER
    - overwrite is True if pick is a return of an ambiguity that needs resolution.
    """
    major_tt, major_value = major
    minor_tt, minor_value = minor

    if major_tt == minor_tt:
        # if it comes from the same revision it must be the same value
        assert major_value == minor_value
        return PICK_EITHER, False
    elif (
        changes is not None
        and minor_value is not None
        and major_value is None
        and dest in changes.salvaged
    ):
        # In this case, a deletion was reverted, the "alive" value overwrite
        # the deleted one.
        return PICK_MINOR, True
    elif (
        changes is not None
        and major_value is not None
        and minor_value is None
        and dest in changes.salvaged
    ):
        # In this case, a deletion was reverted, the "alive" value overwrite
        # the deleted one.
        return PICK_MAJOR, True
    elif isancestor(minor_tt, major_tt):
        if changes is not None and dest in changes.merged:
            # change to dest happened on the branch without copy-source change,
            # so both source are valid and "major" wins.
            return PICK_MAJOR, True
        else:
            return PICK_MAJOR, False
    elif isancestor(major_tt, minor_tt):
        if changes is not None and dest in changes.merged:
            # change to dest happened on the branch without copy-source change,
            # so both source are valid and "major" wins.
            return PICK_MAJOR, True
        else:
            return PICK_MINOR, False
    elif minor_value is None:
        # in case of conflict, the "alive" side wins.
        return PICK_MAJOR, True
    elif major_value is None:
        # in case of conflict, the "alive" side wins.
        return PICK_MINOR, True
    else:
        # in case of conflict where both side are alive, major wins.
        return PICK_MAJOR, True


def _revinfo_getter_extra(repo):
    """return a function that return multiple data given a <rev>"i