Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/sqlalchemy/orm/clsregistry.py: 31%

1# orm/clsregistry.py 

2# Copyright (C) 2005-2024 the SQLAlchemy authors and contributors 

3# <see AUTHORS file> 

4# 

5# This module is part of SQLAlchemy and is released under 

6# the MIT License: https://www.opensource.org/licenses/mit-license.php 

7 

8"""Routines to handle the string class registry used by declarative. 

9 

10This system allows specification of classes and expressions used in 

11:func:`_orm.relationship` using strings. 

12 

13""" 

14 

15from __future__ import annotations 

16 

17import re 

18from typing import Any 

19from typing import Callable 

20from typing import cast 

21from typing import Dict 

22from typing import Generator 

23from typing import Iterable 

24from typing import List 

25from typing import Mapping 

26from typing import MutableMapping 

27from typing import NoReturn 

28from typing import Optional 

29from typing import Set 

30from typing import Tuple 

31from typing import Type 

32from typing import TYPE_CHECKING 

33from typing import TypeVar 

34from typing import Union 

35import weakref 

36 

37from . import attributes 

38from . import interfaces 

39from .descriptor_props import SynonymProperty 

40from .properties import ColumnProperty 

41from .util import class_mapper 

42from .. import exc 

43from .. import inspection 

44from .. import util 

45from ..sql.schema import _get_table_key 

46from ..util.typing import CallableReference 

47 

48if TYPE_CHECKING: 

49 from .relationships import RelationshipProperty 

50 from ..sql.schema import MetaData 

51 from ..sql.schema import Table 

52 

53_T = TypeVar("_T", bound=Any) 

54 

55_ClsRegistryType = MutableMapping[str, Union[type, "ClsRegistryToken"]] 

56 

57# strong references to registries which we place in 

58# the _decl_class_registry, which is usually weak referencing. 

59# the internal registries here link to classes with weakrefs and remove 

60# themselves when all references to contained classes are removed. 

61_registries: Set[ClsRegistryToken] = set() 

62 

63 

64def add_class( 

65 classname: str, cls: Type[_T], decl_class_registry: _ClsRegistryType 

66) -> None: 

67 """Add a class to the _decl_class_registry associated with the 

68 given declarative class. 

69 

70 """ 

71 if classname in decl_class_registry: 

72 # class already exists. 

73 existing = decl_class_registry[classname] 

74 if not isinstance(existing, _MultipleClassMarker): 

75 existing = decl_class_registry[classname] = _MultipleClassMarker( 

76 [cls, cast("Type[Any]", existing)] 

77 ) 

78 else: 

79 decl_class_registry[classname] = cls 

80 

81 try: 

82 root_module = cast( 

83 _ModuleMarker, decl_class_registry["_sa_module_registry"] 

84 ) 

85 except KeyError: 

86 decl_class_registry["_sa_module_registry"] = root_module = ( 

87 _ModuleMarker("_sa_module_registry", None) 

88 ) 

89 

90 tokens = cls.__module__.split(".") 

91 

92 # build up a tree like this: 

93 # modulename: myapp.snacks.nuts 

94 # 

95 # myapp->snack->nuts->(classes) 

96 # snack->nuts->(classes) 

97 # nuts->(classes) 

98 # 

99 # this allows partial token paths to be used. 

100 while tokens: 

101 token = tokens.pop(0) 

102 module = root_module.get_module(token) 

103 for token in tokens: 

104 module = module.get_module(token) 

105 

106 try: 

107 module.add_class(classname, cls) 

108 except AttributeError as ae: 

109 if not isinstance(module, _ModuleMarker): 

110 raise exc.InvalidRequestError( 

111 f'name "{classname}" matches both a ' 

112 "class name and a module name" 

113 ) from ae 

114 else: 

115 raise 

116 

117 

118def remove_class( 

119 classname: str, cls: Type[Any], decl_class_registry: _ClsRegistryType 

120) -> None: 

121 if classname in decl_class_registry: 

122 existing = decl_class_registry[classname] 

123 if isinstance(existing, _MultipleClassMarker): 

124 existing.remove_item(cls) 

125 else: 

126 del decl_class_registry[classname] 

127 

128 try: 

129 root_module = cast( 

130 _ModuleMarker, decl_class_registry["_sa_module_registry"] 

131 ) 

132 except KeyError: 

133 return 

134 

135 tokens = cls.__module__.split(".") 

136 

137 while tokens: 

138 token = tokens.pop(0) 

139 module = root_module.get_module(token) 

140 for token in tokens: 

141 module = module.get_module(token) 

142 try: 

143 module.remove_class(classname, cls) 

144 except AttributeError: 

145 if not isinstance(module, _ModuleMarker): 

146 pass 

147 else: 

148 raise 

149 

150 

151def _key_is_empty( 

152 key: str, 

153 decl_class_registry: _ClsRegistryType, 

154 test: Callable[[Any], bool], 

155) -> bool: 

156 """test if a key is empty of a certain object. 

157 

158 used for unit tests against the registry to see if garbage collection 

159 is working. 

160 

161 "test" is a callable that will be passed an object should return True 

162 if the given object is the one we were looking for. 

163 

164 We can't pass the actual object itself b.c. this is for testing garbage 

165 collection; the caller will have to have removed references to the 

166 object itself. 

167 

168 """ 

169 if key not in decl_class_registry: 

170 return True 

171 

172 thing = decl_class_registry[key] 

173 if isinstance(thing, _MultipleClassMarker): 

174 for sub_thing in thing.contents: 

175 if test(sub_thing): 

176 return False 

177 else: 

178 raise NotImplementedError("unknown codepath") 

179 else: 

180 return not test(thing) 

181 

182 

183class ClsRegistryToken: 

184 """an object that can be in the registry._class_registry as a value.""" 

185 

186 __slots__ = () 

187 

188 

189class _MultipleClassMarker(ClsRegistryToken): 

190 """refers to multiple classes of the same name 

191 within _decl_class_registry. 

192 

193 """ 

194 

195 __slots__ = "on_remove", "contents", "__weakref__" 

196 

197 contents: Set[weakref.ref[Type[Any]]] 

198 on_remove: CallableReference[Optional[Callable[[], None]]] 

199 

200 def __init__( 

201 self, 

202 classes: Iterable[Type[Any]], 

203 on_remove: Optional[Callable[[], None]] = None, 

204 ): 

205 self.on_remove = on_remove 

206 self.contents = { 

207 weakref.ref(item, self._remove_item) for item in classes 

208 } 

209 _registries.add(self) 

210 

211 def remove_item(self, cls: Type[Any]) -> None: 

212 self._remove_item(weakref.ref(cls)) 

213 

214 def __iter__(self) -> Generator[Optional[Type[Any]], None, None]: 

215 return (ref() for ref in self.contents) 

216 

217 def attempt_get(self, path: List[str], key: str) -> Type[Any]: 

218 if len(self.contents) > 1: 

219 raise exc.InvalidRequestError( 

220 'Multiple classes found for path "%s" ' 

221 "in the registry of this declarative " 

222 "base. Please use a fully module-qualified path." 

223 % (".".join(path + [key])) 

224 ) 

225 else: 

226 ref = list(self.contents)[0] 

227 cls = ref() 

228 if cls is None: 

229 raise NameError(key) 

230 return cls 

231 

232 def _remove_item(self, ref: weakref.ref[Type[Any]]) -> None: 

233 self.contents.discard(ref) 

234 if not self.contents: 

235 _registries.discard(self) 

236 if self.on_remove: 

237 self.on_remove() 

238 

239 def add_item(self, item: Type[Any]) -> None: 

240 # protect against class registration race condition against 

241 # asynchronous garbage collection calling _remove_item, 

242 # [ticket:3208] and [ticket:10782] 

243 modules = { 

244 cls.__module__ 

245 for cls in [ref() for ref in list(self.contents)] 

246 if cls is not None 

247 } 

248 if item.__module__ in modules: 

249 util.warn( 

250 "This declarative base already contains a class with the " 

251 "same class name and module name as %s.%s, and will " 

252 "be replaced in the string-lookup table." 

253 % (item.__module__, item.__name__) 

254 ) 

255 self.contents.add(weakref.ref(item, self._remove_item)) 

256 

257 

258class _ModuleMarker(ClsRegistryToken): 

259 """Refers to a module name within 

260 _decl_class_registry. 

261 

262 """ 

263 

264 __slots__ = "parent", "name", "contents", "mod_ns", "path", "__weakref__" 

265 

266 parent: Optional[_ModuleMarker] 

267 contents: Dict[str, Union[_ModuleMarker, _MultipleClassMarker]] 

268 mod_ns: _ModNS 

269 path: List[str] 

270 

271 def __init__(self, name: str, parent: Optional[_ModuleMarker]): 

272 self.parent = parent 

273 self.name = name 

274 self.contents = {} 

275 self.mod_ns = _ModNS(self) 

276 if self.parent: 

277 self.path = self.parent.path + [self.name] 

278 else: 

279 self.path = [] 

280 _registries.add(self) 

281 

282 def __contains__(self, name: str) -> bool: 

283 return name in self.contents 

284 

285 def __getitem__(self, name: str) -> ClsRegistryToken: 

286 return self.contents[name] 

287 

288 def _remove_item(self, name: str) -> None: 

289 self.contents.pop(name, None) 

290 if not self.contents: 

291 if self.parent is not None: 

292 self.parent._remove_item(self.name) 

293 _registries.discard(self) 

294 

295 def resolve_attr(self, key: str) -> Union[_ModNS, Type[Any]]: 

296 return self.mod_ns.__getattr__(key) 

297 

298 def get_module(self, name: str) -> _ModuleMarker: 

299 if name not in self.contents: 

300 marker = _ModuleMarker(name, self) 

301 self.contents[name] = marker 

302 else: 

303 marker = cast(_ModuleMarker, self.contents[name]) 

304 return marker 

305 

306 def add_class(self, name: str, cls: Type[Any]) -> None: 

307 if name in self.contents: 

308 existing = cast(_MultipleClassMarker, self.contents[name]) 

309 try: 

310 existing.add_item(cls) 

311 except AttributeError as ae: 

312 if not isinstance(existing, _MultipleClassMarker): 

313 raise exc.InvalidRequestError( 

314 f'name "{name}" matches both a ' 

315 "class name and a module name" 

316 ) from ae 

317 else: 

318 raise 

319 else: 

320 existing = self.contents[name] = _MultipleClassMarker( 

321 [cls], on_remove=lambda: self._remove_item(name) 

322 ) 

323 

324 def remove_class(self, name: str, cls: Type[Any]) -> None: 

325 if name in self.contents: 

326 existing = cast(_MultipleClassMarker, self.contents[name]) 

327 existing.remove_item(cls) 

328 

329 

330class _ModNS: 

331 __slots__ = ("__parent",) 

332 

333 __parent: _ModuleMarker 

334 

335 def __init__(self, parent: _ModuleMarker): 

336 self.__parent = parent 

337 

338 def __getattr__(self, key: str) -> Union[_ModNS, Type[Any]]: 

339 try: 

340 value = self.__parent.contents[key] 

341 except KeyError: 

342 pass 

343 else: 

344 if value is not None: 

345 if isinstance(value, _ModuleMarker): 

346 return value.mod_ns 

347 else: 

348 assert isinstance(value, _MultipleClassMarker) 

349 return value.attempt_get(self.__parent.path, key) 

350 raise NameError( 

351 "Module %r has no mapped classes " 

352 "registered under the name %r" % (self.__parent.name, key) 

353 ) 

354 

355 

356class _GetColumns: 

357 __slots__ = ("cls",) 

358 

359 cls: Type[Any] 

360 

361 def __init__(self, cls: Type[Any]): 

362 self.cls = cls 

363 

364 def __getattr__(self, key: str) -> Any: 

365 mp = class_mapper(self.cls, configure=False) 

366 if mp: 

367 if key not in mp.all_orm_descriptors: 

368 raise AttributeError( 

369 "Class %r does not have a mapped column named %r" 

370 % (self.cls, key) 

371 ) 

372 

373 desc = mp.all_orm_descriptors[key] 

374 if desc.extension_type is interfaces.NotExtension.NOT_EXTENSION: 

375 assert isinstance(desc, attributes.QueryableAttribute) 

376 prop = desc.property 

377 if isinstance(prop, SynonymProperty): 

378 key = prop.name 

379 elif not isinstance(prop, ColumnProperty): 

380 raise exc.InvalidRequestError( 

381 "Property %r is not an instance of" 

382 " ColumnProperty (i.e. does not correspond" 

383 " directly to a Column)." % key 

384 ) 

385 return getattr(self.cls, key) 

386 

387 

388inspection._inspects(_GetColumns)( 

389 lambda target: inspection.inspect(target.cls) 

390) 

391 

392 

393class _GetTable: 

394 __slots__ = "key", "metadata" 

395 

396 key: str 

397 metadata: MetaData 

398 

399 def __init__(self, key: str, metadata: MetaData): 

400 self.key = key 

401 self.metadata = metadata 

402 

403 def __getattr__(self, key: str) -> Table: 

404 return self.metadata.tables[_get_table_key(key, self.key)] 

405 

406 

407def _determine_container(key: str, value: Any) -> _GetColumns: 

408 if isinstance(value, _MultipleClassMarker): 

409 value = value.attempt_get([], key) 

410 return _GetColumns(value) 

411 

412 

413class _class_resolver: 

414 __slots__ = ( 

415 "cls", 

416 "prop", 

417 "arg", 

418 "fallback", 

419 "_dict", 

420 "_resolvers", 

421 "favor_tables", 

422 ) 

423 

424 cls: Type[Any] 

425 prop: RelationshipProperty[Any] 

426 fallback: Mapping[str, Any] 

427 arg: str 

428 favor_tables: bool 

429 _resolvers: Tuple[Callable[[str], Any], ...] 

430 

431 def __init__( 

432 self, 

433 cls: Type[Any], 

434 prop: RelationshipProperty[Any], 

435 fallback: Mapping[str, Any], 

436 arg: str, 

437 favor_tables: bool = False, 

438 ): 

439 self.cls = cls 

440 self.prop = prop 

441 self.arg = arg 

442 self.fallback = fallback 

443 self._dict = util.PopulateDict(self._access_cls) 

444 self._resolvers = () 

445 self.favor_tables = favor_tables 

446 

447 def _access_cls(self, key: str) -> Any: 

448 cls = self.cls 

449 

450 manager = attributes.manager_of_class(cls) 

451 decl_base = manager.registry 

452 assert decl_base is not None 

453 decl_class_registry = decl_base._class_registry 

454 metadata = decl_base.metadata 

455 

456 if self.favor_tables: 

457 if key in metadata.tables: 

458 return metadata.tables[key] 

459 elif key in metadata._schemas: 

460 return _GetTable(key, getattr(cls, "metadata", metadata)) 

461 

462 if key in decl_class_registry: 

463 return _determine_container(key, decl_class_registry[key]) 

464 

465 if not self.favor_tables: 

466 if key in metadata.tables: 

467 return metadata.tables[key] 

468 elif key in metadata._schemas: 

469 return _GetTable(key, getattr(cls, "metadata", metadata)) 

470 

471 if "_sa_module_registry" in decl_class_registry and key in cast( 

472 _ModuleMarker, decl_class_registry["_sa_module_registry"] 

473 ): 

474 registry = cast( 

475 _ModuleMarker, decl_class_registry["_sa_module_registry"] 

476 ) 

477 return registry.resolve_attr(key) 

478 elif self._resolvers: 

479 for resolv in self._resolvers: 

480 value = resolv(key) 

481 if value is not None: 

482 return value 

483 

484 return self.fallback[key] 

485 

486 def _raise_for_name(self, name: str, err: Exception) -> NoReturn: 

487 generic_match = re.match(r"(.+)\[(.+)\]", name) 

488 

489 if generic_match: 

490 clsarg = generic_match.group(2).strip("'") 

491 raise exc.InvalidRequestError( 

492 f"When initializing mapper {self.prop.parent}, " 

493 f'expression "relationship({self.arg!r})" seems to be ' 

494 "using a generic class as the argument to relationship(); " 

495 "please state the generic argument " 

496 "using an annotation, e.g. " 

497 f'"{self.prop.key}: Mapped[{generic_match.group(1)}' 

498 f"['{clsarg}']] = relationship()\"" 

499 ) from err 

500 else: 

501 raise exc.InvalidRequestError( 

502 "When initializing mapper %s, expression %r failed to " 

503 "locate a name (%r). If this is a class name, consider " 

504 "adding this relationship() to the %r class after " 

505 "both dependent classes have been defined." 

506 % (self.prop.parent, self.arg, name, self.cls) 

507 ) from err 

508 

509 def _resolve_name(self) -> Union[Table, Type[Any], _ModNS]: 

510 name = self.arg 

511 d = self._dict 

512 rval = None 

513 try: 

514 for token in name.split("."): 

515 if rval is None: 

516 rval = d[token] 

517 else: 

518 rval = getattr(rval, token) 

519 except KeyError as err: 

520 self._raise_for_name(name, err) 

521 except NameError as n: 

522 self._raise_for_name(n.args[0], n) 

523 else: 

524 if isinstance(rval, _GetColumns): 

525 return rval.cls 

526 else: 

527 if TYPE_CHECKING: 

528 assert isinstance(rval, (type, Table, _ModNS)) 

529 return rval 

530 

531 def __call__(self) -> Any: 

532 try: 

533 x = eval(self.arg, globals(), self._dict) 

534 

535 if isinstance(x, _GetColumns): 

536 return x.cls 

537 else: 

538 return x 

539 except NameError as n: 

540 self._raise_for_name(n.args[0], n) 

541 

542 

543_fallback_dict: Mapping[str, Any] = None # type: ignore 

544 

545 

546def _resolver(cls: Type[Any], prop: RelationshipProperty[Any]) -> Tuple[ 

547 Callable[[str], Callable[[], Union[Type[Any], Table, _ModNS]]], 

548 Callable[[str, bool], _class_resolver], 

549]: 

550 global _fallback_dict 

551 

552 if _fallback_dict is None: 

553 import sqlalchemy 

554 from . import foreign 

555 from . import remote 

556 

557 _fallback_dict = util.immutabledict(sqlalchemy.__dict__).union( 

558 {"foreign": foreign, "remote": remote} 

559 ) 

560 

561 def resolve_arg(arg: str, favor_tables: bool = False) -> _class_resolver: 

562 return _class_resolver( 

563 cls, prop, _fallback_dict, arg, favor_tables=favor_tables 

564 ) 

565 

566 def resolve_name( 

567 arg: str, 

568 ) -> Callable[[], Union[Type[Any], Table, _ModNS]]: 

569 return _class_resolver(cls, prop, _fallback_dict, arg)._resolve_name 

570 

571 return resolve_name, resolve_arg