Coverage for python/lsst/daf/relation/_materialization.py: 49%
29 statements
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1# This file is part of daf_relation.
2#
3# Developed for the LSST Data Management System.
4# This product includes software developed by the LSST Project
5# (http://www.lsst.org).
6# See the COPYRIGHT file at the top-level directory of this distribution
7# for details of code ownership.
8#
9# This program is free software: you can redistribute it and/or modify
10# it under the terms of the GNU General Public License as published by
11# the Free Software Foundation, either version 3 of the License, or
12# (at your option) any later version.
13#
14# This program is distributed in the hope that it will be useful,
15# but WITHOUT ANY WARRANTY; without even the implied warranty of
16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17# GNU General Public License for more details.
18#
19# You should have received a copy of the GNU General Public License
20# along with this program. If not, see <http://www.gnu.org/licenses/>.
22from __future__ import annotations
24__all__ = ("Materialization",)
26import dataclasses
27from typing import TYPE_CHECKING, Literal, final
29from ._leaf_relation import LeafRelation
30from ._marker_relation import MarkerRelation
32if TYPE_CHECKING: 32 ↛ 33line 32 didn't jump to line 33, because the condition on line 32 was never true
33 from ._relation import Relation
36@final
37@dataclasses.dataclass(frozen=True, kw_only=True)
38class Materialization(MarkerRelation):
39 """A marker operation that indicates that the upstream tree should be
40 evaluated only once, with the results saved and reused for subsequent
41 processing.
43 Materialization is the only provided operation for which
44 `UnaryOperationRelation.is_locked` defaults to `True`.
46 Also unlike most operations, the `~Relation.payload` value for a
47 `Materialization` if frequently not `None`, as this is where
48 engine-specific state is cached for future reuse.
49 """
51 name: str
52 """Name to use for the cached payload within the engine (`str`)."""
54 def __str__(self) -> str:
55 return f"materialize[{self.name!r}]({self.target})"
57 @property
58 def is_locked(self) -> Literal[True]:
59 # Docstring inherited.
60 return True
62 @classmethod
63 def simplify(cls, target: Relation) -> bool:
64 match target:
65 case Materialization():
66 return True
67 case LeafRelation():
68 return True
69 case MarkerRelation(target=new_target):
70 if target.engine == new_target.engine:
71 return cls.simplify(new_target)
72 return False