Method _configure_property

lib/sqlalchemy/orm/mapper.py:2090–2266

(
        self,
        key: str,
        prop_arg: Union[KeyedColumnElement[Any], MapperProperty[Any]],
        *,
        init: bool = True,
        setparent: bool = True,
        warn_for_existing: bool = False,
    )

    @util.preload_module("sqlalchemy.orm.descriptor_props")
    def _configure_property(
        self,
        key: str,
        prop_arg: Union[KeyedColumnElement[Any], MapperProperty[Any]],
        *,
        init: bool = True,
        setparent: bool = True,
        warn_for_existing: bool = False,
    ) -> MapperProperty[Any]:
        descriptor_props = util.preloaded.orm_descriptor_props
        self._log(
            "_configure_property(%s, %s)", key, prop_arg.__class__.__name__
        )

        # early setup mode - don't assign any props, only
        # ensure a Column is turned into a ColumnProperty.
        # see #12858
        early_setup = not hasattr(self, "_props")

        if not isinstance(prop_arg, MapperProperty):
            prop: MapperProperty[Any] = self._property_from_column(
                key, prop_arg, early_setup
            )
        else:
            prop = prop_arg

        if early_setup:
            return prop

        if isinstance(prop, properties.ColumnProperty):
            col = self.persist_selectable.corresponding_column(prop.columns[0])

            # if the column is not present in the mapped table,
            # test if a column has been added after the fact to the
            # parent table (or their parent, etc.) [ticket:1570]
            if col is None and self.inherits:
                path = [self]
                for m in self.inherits.iterate_to_root():
                    col = m.local_table.corresponding_column(prop.columns[0])
                    if col is not None:
                        for m2 in path:
                            m2.persist_selectable._refresh_for_new_column(col)
                        col = self.persist_selectable.corresponding_column(
                            prop.columns[0]
                        )
                        break
                    path.append(m)

            # subquery expression, column not present in the mapped
            # selectable.
            if col is None:
                col = prop.columns[0]

                # column is coming in after _readonly_props was
                # initialized; check for 'readonly'
                if hasattr(self, "_readonly_props") and (
                    not hasattr(col, "table")
                    or col.table not in self._cols_by_table