Method _copy_internals

lib/sqlalchemy/sql/selectable.py:1401–1438

(
        self, clone: _CloneCallableType = _clone, **kw: Any
    )

        )

    def _copy_internals(
        self, clone: _CloneCallableType = _clone, **kw: Any
    ) -> None:
        # see Select._copy_internals() for similar concept

        # here we pre-clone "left" and "right" so that we can
        # determine the new FROM clauses
        all_the_froms = set(
            itertools.chain(
                _from_objects(self.left),
                _from_objects(self.right),
            )
        )

        # run the clone on those.  these will be placed in the
        # cache used by the clone function
        new_froms = {f: clone(f, **kw) for f in all_the_froms}

        # set up a special replace function that will replace for
        # ColumnClause with parent table referring to those
        # replaced FromClause objects
        def replace(
            obj: Union[BinaryExpression[Any], ColumnClause[Any]],
            **kw: Any,
        ) -> Optional[KeyedColumnElement[Any]]:
            if isinstance(obj, ColumnClause) and obj.table in new_froms:
                newelem = new_froms[obj.table].corresponding_column(obj)
                return newelem
            return None

        kw["replace"] = replace

        # run normal _copy_internals.  the clones for
        # left and right will come from the clone function's
        # cache
        super()._copy_internals(clone=clone, **kw)

        self._reset_memoizations()

    def _refresh_for_new_column(self, column: ColumnElement[Any]) -> None:
        super()._refresh_for_new_column(column)