Method generate_revision

alembic/script/base.py:622–772

Generate a new revision file. This runs the ``script.py.mako`` template, given template arguments, and creates a new file. :param revid: String revision id. Typically this comes from ``alembic.util.rev_id()``. :param message: the revision message, the one

(
        self,
        revid: str,
        message: Optional[str],
        head: Optional[_RevIdType] = None,
        splice: Optional[bool] = False,
        branch_labels: Optional[_RevIdType] = None,
        version_path: Union[str, os.PathLike[str], None] = None,
        file_template: Optional[str] = None,
        depends_on: Optional[_RevIdType] = None,
        **kw: Any,
    )

        return create_date

    def generate_revision(
        self,
        revid: str,
        message: Optional[str],
        head: Optional[_RevIdType] = None,
        splice: Optional[bool] = False,
        branch_labels: Optional[_RevIdType] = None,
        version_path: Union[str, os.PathLike[str], None] = None,
        file_template: Optional[str] = None,
        depends_on: Optional[_RevIdType] = None,
        **kw: Any,
    ) -> Optional[Script]:
        """Generate a new revision file.

        This runs the ``script.py.mako`` template, given
        template arguments, and creates a new file.

        :param revid: String revision id.  Typically this
         comes from ``alembic.util.rev_id()``.
        :param message: the revision message, the one passed
         by the -m argument to the ``revision`` command.
        :param head: the head revision to generate against.  Defaults
         to the current "head" if no branches are present, else raises
         an exception.
        :param splice: if True, allow the "head" version to not be an
         actual head; otherwise, the selected head must be a head
         (e.g. endpoint) revision.

        """
        if head is None:
            head = "head"

        try:
            Script.verify_rev_id(revid)
        except revision.RevisionError as err:
            raise util.CommandError(err.args[0]) from err

        with self._catch_revision_errors(
            multiple_heads=(
                "Multiple heads are present; please specify the head "
                "revision on which the new revision should be based, "
                "or perform a merge."
            )
        ):
            heads = cast(
                Tuple[Optional["Revision"], ...],
                self.revision_map.get_revisions(head),
            )
            for h in heads:
                assert h != "base"  # type: ignore[comparison-overlap]

        if len(set(heads)) != len(heads):
            raise util.CommandError("Duplicate head revisions specified")

        create_date = self._generate_create_date()

        if version_path is None:
            if len(self._version_locations) > 1: