| Total Complexity | 146 |
| Total Lines | 1302 |
| Duplicated Lines | 2.3 % |
| Coverage | 0% |
| Changes | 0 | ||
Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like openscap_report.dataclasses.dataclasses often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
| 1 | # pylint: disable=too-many-lines |
||
| 2 | import copy |
||
| 3 | import inspect |
||
| 4 | import keyword |
||
| 5 | import re |
||
| 6 | import sys |
||
| 7 | import types |
||
| 8 | |||
| 9 | __all__ = [ |
||
| 10 | "dataclass", |
||
| 11 | "field", |
||
| 12 | "Field", |
||
| 13 | "FrozenInstanceError", |
||
| 14 | "InitVar", |
||
| 15 | "MISSING", |
||
| 16 | # Helper functions. |
||
| 17 | "fields", |
||
| 18 | "asdict", |
||
| 19 | "astuple", |
||
| 20 | "make_dataclass", |
||
| 21 | "replace", |
||
| 22 | "is_dataclass", |
||
| 23 | ] |
||
| 24 | |||
| 25 | # Conditions for adding methods. The boxes indicate what action the |
||
| 26 | # dataclass decorator takes. For all of these tables, when I talk |
||
| 27 | # about init=, repr=, eq=, order=, unsafe_hash=, or frozen=, I'm |
||
| 28 | # referring to the arguments to the @dataclass decorator. When |
||
| 29 | # checking if a dunder method already exists, I mean check for an |
||
| 30 | # entry in the class's __dict__. I never check to see if an attribute |
||
| 31 | # is defined in a base class. |
||
| 32 | |||
| 33 | # Key: |
||
| 34 | # +=========+=========================================+ |
||
| 35 | # + Value | Meaning | |
||
| 36 | # +=========+=========================================+ |
||
| 37 | # | <blank> | No action: no method is added. | |
||
| 38 | # +---------+-----------------------------------------+ |
||
| 39 | # | add | Generated method is added. | |
||
| 40 | # +---------+-----------------------------------------+ |
||
| 41 | # | raise | TypeError is raised. | |
||
| 42 | # +---------+-----------------------------------------+ |
||
| 43 | # | None | Attribute is set to None. | |
||
| 44 | # +=========+=========================================+ |
||
| 45 | |||
| 46 | # __init__ |
||
| 47 | # |
||
| 48 | # +--- init= parameter |
||
| 49 | # | |
||
| 50 | # v | | | |
||
| 51 | # | no | yes | <--- class has __init__ in __dict__? |
||
| 52 | # +=======+=======+=======+ |
||
| 53 | # | False | | | |
||
| 54 | # +-------+-------+-------+ |
||
| 55 | # | True | add | | <- the default |
||
| 56 | # +=======+=======+=======+ |
||
| 57 | |||
| 58 | # __repr__ |
||
| 59 | # |
||
| 60 | # +--- repr= parameter |
||
| 61 | # | |
||
| 62 | # v | | | |
||
| 63 | # | no | yes | <--- class has __repr__ in __dict__? |
||
| 64 | # +=======+=======+=======+ |
||
| 65 | # | False | | | |
||
| 66 | # +-------+-------+-------+ |
||
| 67 | # | True | add | | <- the default |
||
| 68 | # +=======+=======+=======+ |
||
| 69 | |||
| 70 | |||
| 71 | # __setattr__ |
||
| 72 | # __delattr__ |
||
| 73 | # |
||
| 74 | # +--- frozen= parameter |
||
| 75 | # | |
||
| 76 | # v | | | |
||
| 77 | # | no | yes | <--- class has __setattr__ or __delattr__ in __dict__? |
||
| 78 | # +=======+=======+=======+ |
||
| 79 | # | False | | | <- the default |
||
| 80 | # +-------+-------+-------+ |
||
| 81 | # | True | add | raise | |
||
| 82 | # +=======+=======+=======+ |
||
| 83 | # Raise because not adding these methods would break the "frozen-ness" |
||
| 84 | # of the class. |
||
| 85 | |||
| 86 | # __eq__ |
||
| 87 | # |
||
| 88 | # +--- eq= parameter |
||
| 89 | # | |
||
| 90 | # v | | | |
||
| 91 | # | no | yes | <--- class has __eq__ in __dict__? |
||
| 92 | # +=======+=======+=======+ |
||
| 93 | # | False | | | |
||
| 94 | # +-------+-------+-------+ |
||
| 95 | # | True | add | | <- the default |
||
| 96 | # +=======+=======+=======+ |
||
| 97 | |||
| 98 | # __lt__ |
||
| 99 | # __le__ |
||
| 100 | # __gt__ |
||
| 101 | # __ge__ |
||
| 102 | # |
||
| 103 | # +--- order= parameter |
||
| 104 | # | |
||
| 105 | # v | | | |
||
| 106 | # | no | yes | <--- class has any comparison method in __dict__? |
||
| 107 | # +=======+=======+=======+ |
||
| 108 | # | False | | | <- the default |
||
| 109 | # +-------+-------+-------+ |
||
| 110 | # | True | add | raise | |
||
| 111 | # +=======+=======+=======+ |
||
| 112 | # Raise because to allow this case would interfere with using |
||
| 113 | # functools.total_ordering. |
||
| 114 | |||
| 115 | # __hash__ |
||
| 116 | |||
| 117 | # +------------------- unsafe_hash= parameter |
||
| 118 | # | +----------- eq= parameter |
||
| 119 | # | | +--- frozen= parameter |
||
| 120 | # | | | |
||
| 121 | # v v v | | | |
||
| 122 | # | no | yes | <--- class has explicitly defined __hash__ |
||
| 123 | # +=======+=======+=======+========+========+ |
||
| 124 | # | False | False | False | | | No __eq__, use the base class __hash__ |
||
| 125 | # +-------+-------+-------+--------+--------+ |
||
| 126 | # | False | False | True | | | No __eq__, use the base class __hash__ |
||
| 127 | # +-------+-------+-------+--------+--------+ |
||
| 128 | # | False | True | False | None | | <-- the default, not hashable |
||
| 129 | # +-------+-------+-------+--------+--------+ |
||
| 130 | # | False | True | True | add | | Frozen, so hashable, allows override |
||
| 131 | # +-------+-------+-------+--------+--------+ |
||
| 132 | # | True | False | False | add | raise | Has no __eq__, but hashable |
||
| 133 | # +-------+-------+-------+--------+--------+ |
||
| 134 | # | True | False | True | add | raise | Has no __eq__, but hashable |
||
| 135 | # +-------+-------+-------+--------+--------+ |
||
| 136 | # | True | True | False | add | raise | Not frozen, but hashable |
||
| 137 | # +-------+-------+-------+--------+--------+ |
||
| 138 | # | True | True | True | add | raise | Frozen, so hashable |
||
| 139 | # +=======+=======+=======+========+========+ |
||
| 140 | # For boxes that are blank, __hash__ is untouched and therefore |
||
| 141 | # inherited from the base class. If the base is object, then |
||
| 142 | # id-based hashing is used. |
||
| 143 | # |
||
| 144 | # Note that a class may already have __hash__=None if it specified an |
||
| 145 | # __eq__ method in the class body (not one that was created by |
||
| 146 | # @dataclass). |
||
| 147 | # |
||
| 148 | # See _hash_action (below) for a coded version of this table. |
||
| 149 | |||
| 150 | |||
| 151 | # Raised when an attempt is made to modify a frozen class. |
||
| 152 | class FrozenInstanceError(AttributeError): |
||
| 153 | pass |
||
| 154 | |||
| 155 | |||
| 156 | # A sentinel object for default values to signal that a default |
||
| 157 | # factory will be used. This is given a nice repr() which will appear |
||
| 158 | # in the function signature of dataclasses' constructors. |
||
| 159 | # pylint: disable=invalid-name |
||
| 160 | class _HAS_DEFAULT_FACTORY_CLASS: |
||
| 161 | def __repr__(self): |
||
| 162 | return "<factory>" |
||
| 163 | |||
| 164 | |||
| 165 | _HAS_DEFAULT_FACTORY = _HAS_DEFAULT_FACTORY_CLASS() |
||
| 166 | |||
| 167 | |||
| 168 | # A sentinel object to detect if a parameter is supplied or not. Use |
||
| 169 | # a class to give it a better repr. |
||
| 170 | # pylint: disable=invalid-name |
||
| 171 | class _MISSING_TYPE: |
||
| 172 | pass |
||
| 173 | |||
| 174 | |||
| 175 | MISSING = _MISSING_TYPE() |
||
| 176 | |||
| 177 | # Since most per-field metadata will be unused, create an empty |
||
| 178 | # read-only proxy that can be shared among all fields. |
||
| 179 | _EMPTY_METADATA = types.MappingProxyType({}) |
||
| 180 | |||
| 181 | |||
| 182 | # Markers for the various kinds of fields and pseudo-fields. |
||
| 183 | # pylint: disable=invalid-name |
||
| 184 | class _FIELD_BASE: |
||
| 185 | def __init__(self, name): |
||
| 186 | self.name = name |
||
| 187 | |||
| 188 | def __repr__(self): |
||
| 189 | return self.name |
||
| 190 | |||
| 191 | |||
| 192 | _FIELD = _FIELD_BASE("_FIELD") |
||
| 193 | _FIELD_CLASSVAR = _FIELD_BASE("_FIELD_CLASSVAR") |
||
| 194 | _FIELD_INITVAR = _FIELD_BASE("_FIELD_INITVAR") |
||
| 195 | |||
| 196 | # The name of an attribute on the class where we store the Field |
||
| 197 | # objects. Also used to check if a class is a Data Class. |
||
| 198 | _FIELDS = "__dataclass_fields__" |
||
| 199 | |||
| 200 | # The name of an attribute on the class that stores the parameters to |
||
| 201 | # @dataclass. |
||
| 202 | _PARAMS = "__dataclass_params__" |
||
| 203 | |||
| 204 | # The name of the function, that if it exists, is called at the end of |
||
| 205 | # __init__. |
||
| 206 | _POST_INIT_NAME = "__post_init__" |
||
| 207 | |||
| 208 | # String regex that string annotations for ClassVar or InitVar must match. |
||
| 209 | # Allows "identifier.identifier[" or "identifier[". |
||
| 210 | # https://bugs.python.org/issue33453 for details. |
||
| 211 | _MODULE_IDENTIFIER_RE = re.compile(r"^(?:\s*(\w+)\s*\.)?\s*(\w+)") |
||
| 212 | |||
| 213 | |||
| 214 | class _InitVarMeta(type): |
||
| 215 | def __getitem__(cls, params): |
||
| 216 | return cls |
||
| 217 | |||
| 218 | |||
| 219 | class InitVar(metaclass=_InitVarMeta): |
||
| 220 | pass |
||
| 221 | |||
| 222 | |||
| 223 | # Instances of Field are only ever created from within this module, |
||
| 224 | # and only from the field() function, although Field instances are |
||
| 225 | # exposed externally as (conceptually) read-only objects. |
||
| 226 | # |
||
| 227 | # name and type are filled in after the fact, not in __init__. |
||
| 228 | # They're not known at the time this class is instantiated, but it's |
||
| 229 | # convenient if they're available later. |
||
| 230 | # |
||
| 231 | # When cls._FIELDS is filled in with a list of Field objects, the name |
||
| 232 | # and type fields will have been populated. |
||
| 233 | # pylint: disable=too-many-instance-attributes |
||
| 234 | class Field: |
||
| 235 | __slots__ = ( |
||
| 236 | "name", |
||
| 237 | "type", |
||
| 238 | "default", |
||
| 239 | "default_factory", |
||
| 240 | "repr", |
||
| 241 | "hash", |
||
| 242 | "init", |
||
| 243 | "compare", |
||
| 244 | "metadata", |
||
| 245 | "_field_type", # Private: not to be used by user code. |
||
| 246 | ) |
||
| 247 | |||
| 248 | # pylint: disable=too-many-arguments |
||
| 249 | # pylint: disable=redefined-builtin |
||
| 250 | def __init__(self, default, default_factory, init, repr, hash, compare, metadata): |
||
| 251 | self.name = None |
||
| 252 | self.type = None |
||
| 253 | self.default = default |
||
| 254 | self.default_factory = default_factory |
||
| 255 | self.init = init |
||
| 256 | self.repr = repr |
||
| 257 | self.hash = hash |
||
| 258 | self.compare = compare |
||
| 259 | self.metadata = ( |
||
| 260 | _EMPTY_METADATA |
||
| 261 | if metadata is None or len(metadata) == 0 |
||
| 262 | else types.MappingProxyType(metadata) |
||
| 263 | ) |
||
| 264 | self._field_type = None |
||
| 265 | |||
| 266 | def __repr__(self): |
||
| 267 | return ( |
||
| 268 | "Field(" |
||
| 269 | f"name={self.name!r}," |
||
| 270 | f"type={self.type!r}," |
||
| 271 | f"default={self.default!r}," |
||
| 272 | f"default_factory={self.default_factory!r}," |
||
| 273 | f"init={self.init!r}," |
||
| 274 | f"repr={self.repr!r}," |
||
| 275 | f"hash={self.hash!r}," |
||
| 276 | f"compare={self.compare!r}," |
||
| 277 | f"metadata={self.metadata!r}," |
||
| 278 | f"_field_type={self._field_type}" |
||
| 279 | ")" |
||
| 280 | ) |
||
| 281 | |||
| 282 | # This is used to support the PEP 487 __set_name__ protocol in the |
||
| 283 | # case where we're using a field that contains a descriptor as a |
||
| 284 | # default value. For details on __set_name__, see |
||
| 285 | # https://www.python.org/dev/peps/pep-0487/#implementation-details. |
||
| 286 | # |
||
| 287 | # Note that in _process_class, this Field object is overwritten |
||
| 288 | # with the default value, so the end result is a descriptor that |
||
| 289 | # had __set_name__ called on it at the right time. |
||
| 290 | def __set_name__(self, owner, name): |
||
| 291 | func = getattr(type(self.default), "__set_name__", None) |
||
| 292 | if func: |
||
| 293 | # There is a __set_name__ method on the descriptor, call |
||
| 294 | # it. |
||
| 295 | func(self.default, owner, name) |
||
| 296 | |||
| 297 | |||
| 298 | class _DataclassParams: |
||
| 299 | __slots__ = ( |
||
| 300 | "init", |
||
| 301 | "repr", |
||
| 302 | "eq", |
||
| 303 | "order", |
||
| 304 | "unsafe_hash", |
||
| 305 | "frozen", |
||
| 306 | ) |
||
| 307 | |||
| 308 | # pylint: disable=too-many-arguments |
||
| 309 | # pylint: disable=redefined-builtin |
||
| 310 | def __init__(self, init, repr, eq, order, unsafe_hash, frozen): |
||
| 311 | self.init = init |
||
| 312 | self.repr = repr |
||
| 313 | self.eq = eq |
||
| 314 | self.order = order |
||
| 315 | self.unsafe_hash = unsafe_hash |
||
| 316 | self.frozen = frozen |
||
| 317 | |||
| 318 | def __repr__(self): |
||
| 319 | return ( |
||
| 320 | "_DataclassParams(" |
||
| 321 | f"init={self.init!r}," |
||
| 322 | f"repr={self.repr!r}," |
||
| 323 | f"eq={self.eq!r}," |
||
| 324 | f"order={self.order!r}," |
||
| 325 | f"unsafe_hash={self.unsafe_hash!r}," |
||
| 326 | f"frozen={self.frozen!r}" |
||
| 327 | ")" |
||
| 328 | ) |
||
| 329 | |||
| 330 | |||
| 331 | # This function is used instead of exposing Field creation directly, |
||
| 332 | # so that a type checker can be told (via overloads) that this is a |
||
| 333 | # function whose type depends on its parameters. |
||
| 334 | # pylint: disable=too-many-arguments |
||
| 335 | # pylint: disable=redefined-builtin |
||
| 336 | def field( |
||
| 337 | *, |
||
| 338 | default=MISSING, |
||
| 339 | default_factory=MISSING, |
||
| 340 | init=True, |
||
| 341 | repr=True, |
||
| 342 | hash=None, |
||
| 343 | compare=True, |
||
| 344 | metadata=None, |
||
| 345 | ): |
||
| 346 | """Return an object to identify dataclass fields. |
||
| 347 | |||
| 348 | default is the default value of the field. default_factory is a |
||
| 349 | 0-argument function called to initialize a field's value. If init |
||
| 350 | is True, the field will be a parameter to the class's __init__() |
||
| 351 | function. If repr is True, the field will be included in the |
||
| 352 | object's repr(). If hash is True, the field will be included in |
||
| 353 | the object's hash(). If compare is True, the field will be used |
||
| 354 | in comparison functions. metadata, if specified, must be a |
||
| 355 | mapping which is stored but not otherwise examined by dataclass. |
||
| 356 | |||
| 357 | It is an error to specify both default and default_factory. |
||
| 358 | """ |
||
| 359 | |||
| 360 | if default is not MISSING and default_factory is not MISSING: |
||
| 361 | raise ValueError("cannot specify both default and default_factory") |
||
| 362 | return Field(default, default_factory, init, repr, hash, compare, metadata) |
||
| 363 | |||
| 364 | |||
| 365 | # pylint: disable=redefined-outer-name |
||
| 366 | def _tuple_str(obj_name, fields): |
||
| 367 | # Return a string representing each field of obj_name as a tuple |
||
| 368 | # member. So, if fields is ['x', 'y'] and obj_name is "self", |
||
| 369 | # return "(self.x,self.y)". |
||
| 370 | |||
| 371 | # Special case for the 0-tuple. |
||
| 372 | if not fields: |
||
| 373 | return "()" |
||
| 374 | # Note the trailing comma, needed if this turns out to be a 1-tuple. |
||
| 375 | return f'({",".join([f"{obj_name}.{f.name}" for f in fields])},)' |
||
| 376 | |||
| 377 | |||
| 378 | def _create_fn(name, args, body, *, globals=None, locals=None, return_type=MISSING): |
||
| 379 | # Note that we mutate locals when exec() is called. Caller |
||
| 380 | # beware! The only callers are internal to this module, so no |
||
| 381 | # worries about external callers. |
||
| 382 | if locals is None: |
||
| 383 | locals = {} |
||
| 384 | return_annotation = "" |
||
| 385 | if return_type is not MISSING: |
||
| 386 | locals["_return_type"] = return_type |
||
| 387 | return_annotation = "->_return_type" |
||
| 388 | args = ",".join(args) |
||
| 389 | body = "\n".join(f" {b}" for b in body) |
||
| 390 | |||
| 391 | # Compute the text of the entire function. |
||
| 392 | txt = f"def {name}({args}){return_annotation}:\n{body}" |
||
| 393 | |||
| 394 | # pylint: disable=exec-used |
||
| 395 | exec(txt, globals, locals) |
||
| 396 | return locals[name] |
||
| 397 | |||
| 398 | |||
| 399 | def _field_assign(frozen, name, value, self_name): |
||
| 400 | # If we're a frozen class, then assign to our fields in __init__ |
||
| 401 | # via object.__setattr__. Otherwise, just use a simple |
||
| 402 | # assignment. |
||
| 403 | # |
||
| 404 | # self_name is what "self" is called in this function: don't |
||
| 405 | # hard-code "self", since that might be a field name. |
||
| 406 | if frozen: |
||
| 407 | return f"object.__setattr__({self_name},{name!r},{value})" |
||
| 408 | return f"{self_name}.{name}={value}" |
||
| 409 | |||
| 410 | |||
| 411 | def _field_init(f, frozen, globals, self_name): |
||
| 412 | # Return the text of the line in the body of __init__ that will |
||
| 413 | # initialize this field. |
||
| 414 | |||
| 415 | default_name = f"_dflt_{f.name}" |
||
| 416 | if f.default_factory is not MISSING: |
||
| 417 | if f.init: |
||
| 418 | # This field has a default factory. If a parameter is |
||
| 419 | # given, use it. If not, call the factory. |
||
| 420 | globals[default_name] = f.default_factory |
||
| 421 | value = ( |
||
| 422 | f"{default_name}() " |
||
| 423 | f"if {f.name} is _HAS_DEFAULT_FACTORY " |
||
| 424 | f"else {f.name}" |
||
| 425 | ) |
||
| 426 | else: |
||
| 427 | # This is a field that's not in the __init__ params, but |
||
| 428 | # has a default factory function. It needs to be |
||
| 429 | # initialized here by calling the factory function, |
||
| 430 | # because there's no other way to initialize it. |
||
| 431 | |||
| 432 | # For a field initialized with a default=defaultvalue, the |
||
| 433 | # class dict just has the default value |
||
| 434 | # (cls.fieldname=defaultvalue). But that won't work for a |
||
| 435 | # default factory, the factory must be called in __init__ |
||
| 436 | # and we must assign that to self.fieldname. We can't |
||
| 437 | # fall back to the class dict's value, both because it's |
||
| 438 | # not set, and because it might be different per-class |
||
| 439 | # (which, after all, is why we have a factory function!). |
||
| 440 | |||
| 441 | globals[default_name] = f.default_factory |
||
| 442 | value = f"{default_name}()" |
||
| 443 | else: |
||
| 444 | # No default factory. |
||
| 445 | if f.init: |
||
| 446 | if f.default is MISSING: |
||
| 447 | # There's no default, just do an assignment. |
||
| 448 | value = f.name |
||
| 449 | else: |
||
| 450 | globals[default_name] = f.default |
||
| 451 | value = f.name |
||
| 452 | else: |
||
| 453 | # This field does not need initialization. Signify that |
||
| 454 | # to the caller by returning None. |
||
| 455 | return None |
||
| 456 | |||
| 457 | # Only test this now, so that we can create variables for the |
||
| 458 | # default. However, return None to signify that we're not going |
||
| 459 | # to actually do the assignment statement for InitVars. |
||
| 460 | # pylint: disable=protected-access |
||
| 461 | if f._field_type is _FIELD_INITVAR: |
||
| 462 | return None |
||
| 463 | |||
| 464 | # Now, actually generate the field assignment. |
||
| 465 | return _field_assign(frozen, f.name, value, self_name) |
||
| 466 | |||
| 467 | |||
| 468 | def _init_param(f): |
||
| 469 | # Return the __init__ parameter string for this field. For |
||
| 470 | # example, the equivalent of 'x:int=3' (except instead of 'int', |
||
| 471 | # reference a variable set to int, and instead of '3', reference a |
||
| 472 | # variable set to 3). |
||
| 473 | default = None |
||
| 474 | if f.default is MISSING and f.default_factory is MISSING: |
||
| 475 | # There's no default, and no default_factory, just output the |
||
| 476 | # variable name and type. |
||
| 477 | default = "" |
||
| 478 | elif f.default is not MISSING: |
||
| 479 | # There's a default, this will be the name that's used to look |
||
| 480 | # it up. |
||
| 481 | default = f"=_dflt_{f.name}" |
||
| 482 | elif f.default_factory is not MISSING: |
||
| 483 | # There's a factory function. Set a marker. |
||
| 484 | default = "=_HAS_DEFAULT_FACTORY" |
||
| 485 | return f"{f.name}:_type_{f.name}{default}" |
||
| 486 | |||
| 487 | |||
| 488 | def _init_fn(fields, frozen, has_post_init, self_name): |
||
| 489 | # fields contains both real fields and InitVar pseudo-fields. |
||
| 490 | |||
| 491 | # Make sure we don't have fields without defaults following fields |
||
| 492 | # with defaults. This actually would be caught when exec-ing the |
||
| 493 | # function source code, but catching it here gives a better error |
||
| 494 | # message, and future-proofs us in case we build up the function |
||
| 495 | # using ast. |
||
| 496 | seen_default = False |
||
| 497 | for f in fields: |
||
| 498 | # Only consider fields in the __init__ call. |
||
| 499 | if f.init: |
||
| 500 | if not (f.default is MISSING and f.default_factory is MISSING): |
||
| 501 | seen_default = True |
||
| 502 | elif seen_default: |
||
| 503 | raise TypeError( |
||
| 504 | f"non-default argument {f.name!r} " "follows default argument" |
||
| 505 | ) |
||
| 506 | |||
| 507 | globals = {"MISSING": MISSING, "_HAS_DEFAULT_FACTORY": _HAS_DEFAULT_FACTORY} |
||
| 508 | |||
| 509 | body_lines = [] |
||
| 510 | for f in fields: |
||
| 511 | line = _field_init(f, frozen, globals, self_name) |
||
| 512 | # line is None means that this field doesn't require |
||
| 513 | # initialization (it's a pseudo-field). Just skip it. |
||
| 514 | if line: |
||
| 515 | body_lines.append(line) |
||
| 516 | |||
| 517 | # Does this class have a post-init function? |
||
| 518 | if has_post_init: |
||
| 519 | # pylint: disable=protected-access |
||
| 520 | params_str = ",".join(f.name for f in fields if f._field_type is _FIELD_INITVAR) |
||
| 521 | body_lines.append(f"{self_name}.{_POST_INIT_NAME}({params_str})") |
||
| 522 | |||
| 523 | # If no body lines, use 'pass'. |
||
| 524 | if not body_lines: |
||
| 525 | body_lines = ["pass"] |
||
| 526 | |||
| 527 | locals = {f"_type_{f.name}": f.type for f in fields} |
||
| 528 | return _create_fn( |
||
| 529 | "__init__", |
||
| 530 | [self_name] + [_init_param(f) for f in fields if f.init], |
||
| 531 | body_lines, |
||
| 532 | locals=locals, |
||
| 533 | globals=globals, |
||
| 534 | return_type=None, |
||
| 535 | ) |
||
| 536 | |||
| 537 | |||
| 538 | def _repr_fn(fields): |
||
| 539 | return _create_fn( |
||
| 540 | "__repr__", |
||
| 541 | ("self",), |
||
| 542 | [ |
||
| 543 | 'return self.__class__.__qualname__ + f"(' |
||
| 544 | + ", ".join([f"{f.name}={{self.{f.name}!r}}" for f in fields]) # noqa: W503 |
||
| 545 | + ')"' # noqa: W503 |
||
| 546 | ], |
||
| 547 | ) |
||
| 548 | |||
| 549 | |||
| 550 | def _frozen_get_del_attr(cls, fields): |
||
| 551 | # pylint: disable=fixme |
||
| 552 | # XXX: globals is modified on the first call to _create_fn, then |
||
| 553 | # the modified version is used in the second call. Is this okay? |
||
| 554 | globals = {"cls": cls, "FrozenInstanceError": FrozenInstanceError} |
||
| 555 | if fields: |
||
| 556 | fields_str = "(" + ",".join(repr(f.name) for f in fields) + ",)" |
||
| 557 | else: |
||
| 558 | # Special case for the zero-length tuple. |
||
| 559 | fields_str = "()" |
||
| 560 | return ( |
||
| 561 | _create_fn( |
||
| 562 | "__setattr__", |
||
| 563 | ("self", "name", "value"), |
||
| 564 | ( |
||
| 565 | f"if type(self) is cls or name in {fields_str}:", |
||
| 566 | ' raise FrozenInstanceError(f"cannot assign to field {name!r}")', |
||
| 567 | "super(cls, self).__setattr__(name, value)", |
||
| 568 | ), |
||
| 569 | globals=globals, |
||
| 570 | ), |
||
| 571 | _create_fn( |
||
| 572 | "__delattr__", |
||
| 573 | ("self", "name"), |
||
| 574 | ( |
||
| 575 | f"if type(self) is cls or name in {fields_str}:", |
||
| 576 | ' raise FrozenInstanceError(f"cannot delete field {name!r}")', |
||
| 577 | "super(cls, self).__delattr__(name)", |
||
| 578 | ), |
||
| 579 | globals=globals, |
||
| 580 | ), |
||
| 581 | ) |
||
| 582 | |||
| 583 | |||
| 584 | def _cmp_fn(name, op, self_tuple, other_tuple): |
||
| 585 | # Create a comparison function. If the fields in the object are |
||
| 586 | # named 'x' and 'y', then self_tuple is the string |
||
| 587 | # '(self.x,self.y)' and other_tuple is the string |
||
| 588 | # '(other.x,other.y)'. |
||
| 589 | |||
| 590 | return _create_fn( |
||
| 591 | name, |
||
| 592 | ("self", "other"), |
||
| 593 | [ |
||
| 594 | "if other.__class__ is self.__class__:", |
||
| 595 | f" return {self_tuple}{op}{other_tuple}", |
||
| 596 | "return NotImplemented", |
||
| 597 | ], |
||
| 598 | ) |
||
| 599 | |||
| 600 | |||
| 601 | def _hash_fn(fields): |
||
| 602 | self_tuple = _tuple_str("self", fields) |
||
| 603 | return _create_fn("__hash__", ("self",), [f"return hash({self_tuple})"]) |
||
| 604 | |||
| 605 | |||
| 606 | def _is_classvar(a_type, typing): |
||
| 607 | # This test uses a typing internal class, but it's the best way to |
||
| 608 | # test if this is a ClassVar. |
||
| 609 | # pylint: disable=protected-access |
||
| 610 | # pylint: disable=unidiomatic-typecheck |
||
| 611 | return type(a_type) is typing._ClassVar |
||
| 612 | |||
| 613 | |||
| 614 | def _is_initvar(a_type, dataclasses): |
||
| 615 | # The module we're checking against is the module we're |
||
| 616 | # currently in (dataclasses.py). |
||
| 617 | return a_type is dataclasses.InitVar |
||
| 618 | |||
| 619 | |||
| 620 | def _is_type(annotation, cls, a_module, a_type, is_type_predicate): |
||
| 621 | # Given a type annotation string, does it refer to a_type in |
||
| 622 | # a_module? For example, when checking that annotation denotes a |
||
| 623 | # ClassVar, then a_module is typing, and a_type is |
||
| 624 | # typing.ClassVar. |
||
| 625 | |||
| 626 | # It's possible to look up a_module given a_type, but it involves |
||
| 627 | # looking in sys.modules (again!), and seems like a waste since |
||
| 628 | # the caller already knows a_module. |
||
| 629 | |||
| 630 | # - annotation is a string type annotation |
||
| 631 | # - cls is the class that this annotation was found in |
||
| 632 | # - a_module is the module we want to match |
||
| 633 | # - a_type is the type in that module we want to match |
||
| 634 | # - is_type_predicate is a function called with (obj, a_module) |
||
| 635 | # that determines if obj is of the desired type. |
||
| 636 | |||
| 637 | # Since this test does not do a local namespace lookup (and |
||
| 638 | # instead only a module (global) lookup), there are some things it |
||
| 639 | # gets wrong. |
||
| 640 | |||
| 641 | # With string annotations, cv0 will be detected as a ClassVar: |
||
| 642 | # CV = ClassVar |
||
| 643 | # @dataclass |
||
| 644 | # class C0: |
||
| 645 | # cv0: CV |
||
| 646 | |||
| 647 | # But in this example cv1 will not be detected as a ClassVar: |
||
| 648 | # @dataclass |
||
| 649 | # class C1: |
||
| 650 | # CV = ClassVar |
||
| 651 | # cv1: CV |
||
| 652 | |||
| 653 | # In C1, the code in this function (_is_type) will look up "CV" in |
||
| 654 | # the module and not find it, so it will not consider cv1 as a |
||
| 655 | # ClassVar. This is a fairly obscure corner case, and the best |
||
| 656 | # way to fix it would be to eval() the string "CV" with the |
||
| 657 | # correct global and local namespaces. However that would involve |
||
| 658 | # a eval() penalty for every single field of every dataclass |
||
| 659 | # that's defined. It was judged not worth it. |
||
| 660 | |||
| 661 | match = _MODULE_IDENTIFIER_RE.match(annotation) |
||
| 662 | if match: |
||
| 663 | ns = None |
||
| 664 | module_name = match.group(1) |
||
| 665 | if not module_name: |
||
| 666 | # No module name, assume the class's module did |
||
| 667 | # "from .dataclasses import InitVar". |
||
| 668 | ns = sys.modules.get(cls.__module__).__dict__ |
||
| 669 | else: |
||
| 670 | # Look up module_name in the class's module. |
||
| 671 | module = sys.modules.get(cls.__module__) |
||
| 672 | if module and module.__dict__.get(module_name) is a_module: |
||
| 673 | ns = sys.modules.get(a_type.__module__).__dict__ |
||
| 674 | if ns and is_type_predicate(ns.get(match.group(2)), a_module): |
||
| 675 | return True |
||
| 676 | return False |
||
| 677 | |||
| 678 | |||
| 679 | def _get_field(cls, a_name, a_type): |
||
| 680 | # Return a Field object for this field name and type. ClassVars |
||
| 681 | # and InitVars are also returned, but marked as such (see |
||
| 682 | # f._field_type). |
||
| 683 | |||
| 684 | # If the default value isn't derived from Field, then it's only a |
||
| 685 | # normal default value. Convert it to a Field(). |
||
| 686 | default = getattr(cls, a_name, MISSING) |
||
| 687 | if isinstance(default, Field): |
||
| 688 | f = default |
||
| 689 | else: |
||
| 690 | if isinstance(default, types.MemberDescriptorType): |
||
| 691 | # This is a field in __slots__, so it has no default value. |
||
| 692 | default = MISSING |
||
| 693 | f = field(default=default) |
||
| 694 | |||
| 695 | # Only at this point do we know the name and the type. Set them. |
||
| 696 | f.name = a_name |
||
| 697 | f.type = a_type |
||
| 698 | |||
| 699 | # Assume it's a normal field until proven otherwise. We're next |
||
| 700 | # going to decide if it's a ClassVar or InitVar, everything else |
||
| 701 | # is just a normal field. |
||
| 702 | # pylint: disable=protected-access |
||
| 703 | f._field_type = _FIELD |
||
| 704 | |||
| 705 | # In addition to checking for actual types here, also check for |
||
| 706 | # string annotations. get_type_hints() won't always work for us |
||
| 707 | # (see https://github.com/python/typing/issues/508 for example), |
||
| 708 | # plus it's expensive and would require an eval for every string |
||
| 709 | # annotation. So, make a best effort to see if this is a ClassVar |
||
| 710 | # or InitVar using regex's and checking that the thing referenced |
||
| 711 | # is actually of the correct type. |
||
| 712 | |||
| 713 | # For the complete discussion, see https://bugs.python.org/issue33453 |
||
| 714 | |||
| 715 | # If typing has not been imported, then it's impossible for any |
||
| 716 | # annotation to be a ClassVar. So, only look for ClassVar if |
||
| 717 | # typing has been imported by any module (not necessarily cls's |
||
| 718 | # module). |
||
| 719 | typing = sys.modules.get("typing") |
||
| 720 | if typing: |
||
| 721 | if _is_classvar(a_type, typing) or ( |
||
| 722 | isinstance(f.type, str) |
||
| 723 | and _is_type(f.type, cls, typing, typing.ClassVar, _is_classvar) # noqa: W503 |
||
| 724 | ): |
||
| 725 | # pylint: disable=protected-access |
||
| 726 | f._field_type = _FIELD_CLASSVAR |
||
| 727 | |||
| 728 | # If the type is InitVar, or if it's a matching string annotation, |
||
| 729 | # then it's an InitVar. |
||
| 730 | # pylint: disable=protected-access |
||
| 731 | if f._field_type is _FIELD: |
||
| 732 | # The module we're checking against is the module we're |
||
| 733 | # currently in (dataclasses.py). |
||
| 734 | dataclasses = sys.modules[__name__] |
||
| 735 | if _is_initvar(a_type, dataclasses) or ( |
||
| 736 | isinstance(f.type, str) |
||
| 737 | and _is_type(f.type, cls, dataclasses, dataclasses.InitVar, _is_initvar) # noqa: W503 |
||
| 738 | ): |
||
| 739 | # pylint: disable=protected-access |
||
| 740 | f._field_type = _FIELD_INITVAR |
||
| 741 | |||
| 742 | # Validations for individual fields. This is delayed until now, |
||
| 743 | # instead of in the Field() constructor, since only here do we |
||
| 744 | # know the field name, which allows for better error reporting. |
||
| 745 | |||
| 746 | # Special restrictions for ClassVar and InitVar. |
||
| 747 | # pylint: disable=protected-access |
||
| 748 | if f._field_type in (_FIELD_CLASSVAR, _FIELD_INITVAR): |
||
| 749 | if f.default_factory is not MISSING: |
||
| 750 | raise TypeError(f"field {f.name} cannot have a " "default factory") |
||
| 751 | # Should I check for other field settings? default_factory |
||
| 752 | # seems the most serious to check for. Maybe add others. For |
||
| 753 | # example, how about init=False (or really, |
||
| 754 | # init=<not-the-default-init-value>)? It makes no sense for |
||
| 755 | # ClassVar and InitVar to specify init=<anything>. |
||
| 756 | |||
| 757 | # For real fields, disallow mutable defaults for known types. |
||
| 758 | # pylint: disable=protected-access |
||
| 759 | if f._field_type is _FIELD and isinstance(f.default, (list, dict, set)): |
||
| 760 | raise ValueError( |
||
| 761 | f"mutable default {type(f.default)} for field " |
||
| 762 | f"{f.name} is not allowed: use default_factory" |
||
| 763 | ) |
||
| 764 | |||
| 765 | return f |
||
| 766 | |||
| 767 | |||
| 768 | def _set_new_attribute(cls, name, value): |
||
| 769 | # Never overwrites an existing attribute. Returns True if the |
||
| 770 | # attribute already exists. |
||
| 771 | if name in cls.__dict__: |
||
| 772 | return True |
||
| 773 | setattr(cls, name, value) |
||
| 774 | return False |
||
| 775 | |||
| 776 | |||
| 777 | # Decide if/how we're going to create a hash function. Key is |
||
| 778 | # (unsafe_hash, eq, frozen, does-hash-exist). Value is the action to |
||
| 779 | # take. The common case is to do nothing, so instead of providing a |
||
| 780 | # function that is a no-op, use None to signify that. |
||
| 781 | |||
| 782 | # pylint: disable=unused-argument |
||
| 783 | def _hash_set_none(cls, fields): |
||
| 784 | return None |
||
| 785 | |||
| 786 | |||
| 787 | # pylint: disable=unused-argument |
||
| 788 | def _hash_add(cls, fields): |
||
| 789 | flds = [f for f in fields if (f.compare if f.hash is None else f.hash)] |
||
| 790 | return _hash_fn(flds) |
||
| 791 | |||
| 792 | |||
| 793 | def _hash_exception(cls, fields): |
||
| 794 | # Raise an exception. |
||
| 795 | raise TypeError(f"Cannot overwrite attribute __hash__ " f"in class {cls.__name__}") |
||
| 796 | |||
| 797 | |||
| 798 | # |
||
| 799 | # +-------------------------------------- unsafe_hash? |
||
| 800 | # | +------------------------------- eq? |
||
| 801 | # | | +------------------------ frozen? |
||
| 802 | # | | | +---------------- has-explicit-hash? |
||
| 803 | # | | | | |
||
| 804 | # | | | | +------- action |
||
| 805 | # | | | | | |
||
| 806 | # v v v v v |
||
| 807 | _hash_action = { |
||
| 808 | (False, False, False, False): None, |
||
| 809 | (False, False, False, True): None, |
||
| 810 | (False, False, True, False): None, |
||
| 811 | (False, False, True, True): None, |
||
| 812 | (False, True, False, False): _hash_set_none, |
||
| 813 | (False, True, False, True): None, |
||
| 814 | (False, True, True, False): _hash_add, |
||
| 815 | (False, True, True, True): None, |
||
| 816 | (True, False, False, False): _hash_add, |
||
| 817 | (True, False, False, True): _hash_exception, |
||
| 818 | (True, False, True, False): _hash_add, |
||
| 819 | (True, False, True, True): _hash_exception, |
||
| 820 | (True, True, False, False): _hash_add, |
||
| 821 | (True, True, False, True): _hash_exception, |
||
| 822 | (True, True, True, False): _hash_add, |
||
| 823 | (True, True, True, True): _hash_exception, |
||
| 824 | } |
||
| 825 | # See https://bugs.python.org/issue32929#msg312829 for an if-statement |
||
| 826 | # version of this table. |
||
| 827 | |||
| 828 | |||
| 829 | # pylint: disable=too-many-locals |
||
| 830 | # pylint: disable=too-many-branches |
||
| 831 | # pylint: disable=too-many-statements |
||
| 832 | def _process_class(cls, init, repr, eq, order, unsafe_hash, frozen): # noqa: C901 |
||
| 833 | # Now that dicts retain insertion order, there's no reason to use |
||
| 834 | # an ordered dict. I am leveraging that ordering here, because |
||
| 835 | # derived class fields overwrite base class fields, but the order |
||
| 836 | # is defined by the base class, which is found first. |
||
| 837 | fields = {} |
||
| 838 | |||
| 839 | setattr(cls, _PARAMS, _DataclassParams(init, repr, eq, order, unsafe_hash, frozen)) |
||
| 840 | |||
| 841 | # Find our base classes in reverse MRO order, and exclude |
||
| 842 | # ourselves. In reversed order so that more derived classes |
||
| 843 | # override earlier field definitions in base classes. As long as |
||
| 844 | # we're iterating over them, see if any are frozen. |
||
| 845 | any_frozen_base = False |
||
| 846 | has_dataclass_bases = False |
||
| 847 | for b in cls.__mro__[-1:0:-1]: |
||
| 848 | # Only process classes that have been processed by our |
||
| 849 | # decorator. That is, they have a _FIELDS attribute. |
||
| 850 | base_fields = getattr(b, _FIELDS, None) |
||
| 851 | if base_fields: |
||
| 852 | has_dataclass_bases = True |
||
| 853 | for f in base_fields.values(): |
||
| 854 | fields[f.name] = f |
||
| 855 | if getattr(b, _PARAMS).frozen: |
||
| 856 | any_frozen_base = True |
||
| 857 | |||
| 858 | # Annotations that are defined in this class (not in base |
||
| 859 | # classes). If __annotations__ isn't present, then this class |
||
| 860 | # adds no new annotations. We use this to compute fields that are |
||
| 861 | # added by this class. |
||
| 862 | # |
||
| 863 | # Fields are found from cls_annotations, which is guaranteed to be |
||
| 864 | # ordered. Default values are from class attributes, if a field |
||
| 865 | # has a default. If the default value is a Field(), then it |
||
| 866 | # contains additional info beyond (and possibly including) the |
||
| 867 | # actual default value. Pseudo-fields ClassVars and InitVars are |
||
| 868 | # included, despite the fact that they're not real fields. That's |
||
| 869 | # dealt with later. |
||
| 870 | cls_annotations = cls.__dict__.get("__annotations__", {}) |
||
| 871 | |||
| 872 | # Now find fields in our class. While doing so, validate some |
||
| 873 | # things, and set the default values (as class attributes) where |
||
| 874 | # we can. |
||
| 875 | cls_fields = [_get_field(cls, name, type) for name, type in cls_annotations.items()] |
||
| 876 | for f in cls_fields: |
||
| 877 | fields[f.name] = f |
||
| 878 | |||
| 879 | # If the class attribute (which is the default value for this |
||
| 880 | # field) exists and is of type 'Field', replace it with the |
||
| 881 | # real default. This is so that normal class introspection |
||
| 882 | # sees a real default value, not a Field. |
||
| 883 | if isinstance(getattr(cls, f.name, None), Field): |
||
| 884 | if f.default is MISSING: |
||
| 885 | # If there's no default, delete the class attribute. |
||
| 886 | # This happens if we specify field(repr=False), for |
||
| 887 | # example (that is, we specified a field object, but |
||
| 888 | # no default value). Also if we're using a default |
||
| 889 | # factory. The class attribute should not be set at |
||
| 890 | # all in the post-processed class. |
||
| 891 | delattr(cls, f.name) |
||
| 892 | else: |
||
| 893 | setattr(cls, f.name, f.default) |
||
| 894 | |||
| 895 | # Do we have any Field members that don't also have annotations? |
||
| 896 | for name, value in cls.__dict__.items(): |
||
| 897 | if isinstance(value, Field) and name not in cls_annotations: |
||
| 898 | raise TypeError(f"{name!r} is a field but has no type annotation") |
||
| 899 | |||
| 900 | # Check rules that apply if we are derived from any dataclasses. |
||
| 901 | if has_dataclass_bases: |
||
| 902 | # Raise an exception if any of our bases are frozen, but we're not. |
||
| 903 | if any_frozen_base and not frozen: |
||
| 904 | raise TypeError("cannot inherit non-frozen dataclass from a frozen one") |
||
| 905 | |||
| 906 | # Raise an exception if we're frozen, but none of our bases are. |
||
| 907 | if not any_frozen_base and frozen: |
||
| 908 | raise TypeError("cannot inherit frozen dataclass from a non-frozen one") |
||
| 909 | |||
| 910 | # Remember all of the fields on our class (including bases). This |
||
| 911 | # also marks this class as being a dataclass. |
||
| 912 | setattr(cls, _FIELDS, fields) |
||
| 913 | |||
| 914 | # Was this class defined with an explicit __hash__? Note that if |
||
| 915 | # __eq__ is defined in this class, then python will automatically |
||
| 916 | # set __hash__ to None. This is a heuristic, as it's possible |
||
| 917 | # that such a __hash__ == None was not auto-generated, but it |
||
| 918 | # close enough. |
||
| 919 | class_hash = cls.__dict__.get("__hash__", MISSING) |
||
| 920 | has_explicit_hash = not ( |
||
| 921 | class_hash is MISSING or (class_hash is None and "__eq__" in cls.__dict__) |
||
| 922 | ) |
||
| 923 | |||
| 924 | # If we're generating ordering methods, we must be generating the |
||
| 925 | # eq methods. |
||
| 926 | if order and not eq: |
||
| 927 | raise ValueError("eq must be true if order is true") |
||
| 928 | |||
| 929 | if init: |
||
| 930 | # Does this class have a post-init function? |
||
| 931 | has_post_init = hasattr(cls, _POST_INIT_NAME) |
||
| 932 | |||
| 933 | # Include InitVars and regular fields (so, not ClassVars). |
||
| 934 | # pylint: disable=protected-access |
||
| 935 | flds = [f for f in fields.values() if f._field_type in (_FIELD, _FIELD_INITVAR)] |
||
| 936 | _set_new_attribute( |
||
| 937 | cls, |
||
| 938 | "__init__", |
||
| 939 | _init_fn( |
||
| 940 | flds, |
||
| 941 | frozen, |
||
| 942 | has_post_init, |
||
| 943 | # The name to use for the "self" |
||
| 944 | # param in __init__. Use "self" |
||
| 945 | # if possible. |
||
| 946 | "__dataclass_self__" if "self" in fields else "self", |
||
| 947 | ), |
||
| 948 | ) |
||
| 949 | |||
| 950 | # Get the fields as a list, and include only real fields. This is |
||
| 951 | # used in all of the following methods. |
||
| 952 | # pylint: disable=protected-access |
||
| 953 | field_list = [f for f in fields.values() if f._field_type is _FIELD] |
||
| 954 | |||
| 955 | if repr: |
||
| 956 | flds = [f for f in field_list if f.repr] |
||
| 957 | _set_new_attribute(cls, "__repr__", _repr_fn(flds)) |
||
| 958 | |||
| 959 | if eq: |
||
| 960 | # Create _eq__ method. There's no need for a __ne__ method, |
||
| 961 | # since python will call __eq__ and negate it. |
||
| 962 | flds = [f for f in field_list if f.compare] |
||
| 963 | self_tuple = _tuple_str("self", flds) |
||
| 964 | other_tuple = _tuple_str("other", flds) |
||
| 965 | _set_new_attribute( |
||
| 966 | cls, "__eq__", _cmp_fn("__eq__", "==", self_tuple, other_tuple) |
||
| 967 | ) |
||
| 968 | |||
| 969 | if order: |
||
| 970 | # Create and set the ordering methods. |
||
| 971 | flds = [f for f in field_list if f.compare] |
||
| 972 | self_tuple = _tuple_str("self", flds) |
||
| 973 | other_tuple = _tuple_str("other", flds) |
||
| 974 | for name, op in [ |
||
| 975 | ("__lt__", "<"), |
||
| 976 | ("__le__", "<="), |
||
| 977 | ("__gt__", ">"), |
||
| 978 | ("__ge__", ">="), |
||
| 979 | ]: |
||
| 980 | if _set_new_attribute( |
||
| 981 | cls, name, _cmp_fn(name, op, self_tuple, other_tuple) |
||
| 982 | ): |
||
| 983 | raise TypeError( |
||
| 984 | f"Cannot overwrite attribute {name} " |
||
| 985 | f"in class {cls.__name__}. Consider using " |
||
| 986 | "functools.total_ordering" |
||
| 987 | ) |
||
| 988 | |||
| 989 | if frozen: |
||
| 990 | for fn in _frozen_get_del_attr(cls, field_list): |
||
| 991 | if _set_new_attribute(cls, fn.__name__, fn): |
||
| 992 | raise TypeError( |
||
| 993 | f"Cannot overwrite attribute {fn.__name__} " |
||
| 994 | f"in class {cls.__name__}" |
||
| 995 | ) |
||
| 996 | |||
| 997 | # Decide if/how we're going to create a hash function. |
||
| 998 | hash_action = _hash_action[ |
||
| 999 | bool(unsafe_hash), bool(eq), bool(frozen), has_explicit_hash |
||
| 1000 | ] |
||
| 1001 | if hash_action: |
||
| 1002 | # No need to call _set_new_attribute here, since by the time |
||
| 1003 | # we're here the overwriting is unconditional. |
||
| 1004 | cls.__hash__ = hash_action(cls, field_list) |
||
| 1005 | |||
| 1006 | if not getattr(cls, "__doc__"): |
||
| 1007 | # Create a class doc-string. |
||
| 1008 | cls.__doc__ = cls.__name__ + str(inspect.signature(cls)).replace(" -> None", "") |
||
| 1009 | |||
| 1010 | return cls |
||
| 1011 | |||
| 1012 | |||
| 1013 | # _cls should never be specified by keyword, so start it with an |
||
| 1014 | # underscore. The presence of _cls is used to detect if this |
||
| 1015 | # decorator is being called with parameters or not. |
||
| 1016 | def dataclass( |
||
| 1017 | _cls=None, |
||
| 1018 | *, |
||
| 1019 | init=True, |
||
| 1020 | repr=True, |
||
| 1021 | eq=True, |
||
| 1022 | order=False, |
||
| 1023 | unsafe_hash=False, |
||
| 1024 | frozen=False, |
||
| 1025 | ): |
||
| 1026 | """Returns the same class as was passed in, with dunder methods |
||
| 1027 | added based on the fields defined in the class. |
||
| 1028 | |||
| 1029 | Examines PEP 526 __annotations__ to determine fields. |
||
| 1030 | |||
| 1031 | If init is true, an __init__() method is added to the class. If |
||
| 1032 | repr is true, a __repr__() method is added. If order is true, rich |
||
| 1033 | comparison dunder methods are added. If unsafe_hash is true, a |
||
| 1034 | __hash__() method function is added. If frozen is true, fields may |
||
| 1035 | not be assigned to after instance creation. |
||
| 1036 | """ |
||
| 1037 | |||
| 1038 | def wrap(cls): |
||
| 1039 | return _process_class(cls, init, repr, eq, order, unsafe_hash, frozen) |
||
| 1040 | |||
| 1041 | # See if we're being called as @dataclass or @dataclass(). |
||
| 1042 | if _cls is None: |
||
| 1043 | # We're called with parens. |
||
| 1044 | return wrap |
||
| 1045 | |||
| 1046 | # We're called as @dataclass without parens. |
||
| 1047 | return wrap(_cls) |
||
| 1048 | |||
| 1049 | |||
| 1050 | def fields(class_or_instance): |
||
| 1051 | """Return a tuple describing the fields of this dataclass. |
||
| 1052 | |||
| 1053 | Accepts a dataclass or an instance of one. Tuple elements are of |
||
| 1054 | type Field. |
||
| 1055 | """ |
||
| 1056 | |||
| 1057 | # Might it be worth caching this, per class? |
||
| 1058 | try: |
||
| 1059 | fields = getattr(class_or_instance, _FIELDS) |
||
| 1060 | except AttributeError: |
||
| 1061 | # pylint: disable=raise-missing-from |
||
| 1062 | raise TypeError("must be called with a dataclass type or instance") |
||
| 1063 | |||
| 1064 | # Exclude pseudo-fields. Note that fields is sorted by insertion |
||
| 1065 | # order, so the order of the tuple is as the fields were defined. |
||
| 1066 | # pylint: disable=protected-access |
||
| 1067 | return tuple(f for f in fields.values() if f._field_type is _FIELD) |
||
| 1068 | |||
| 1069 | |||
| 1070 | def _is_dataclass_instance(obj): |
||
| 1071 | """Returns True if obj is an instance of a dataclass.""" |
||
| 1072 | return not isinstance(obj, type) and hasattr(obj, _FIELDS) |
||
| 1073 | |||
| 1074 | |||
| 1075 | def is_dataclass(obj): |
||
| 1076 | """Returns True if obj is a dataclass or an instance of a |
||
| 1077 | dataclass.""" |
||
| 1078 | return hasattr(obj, _FIELDS) |
||
| 1079 | |||
| 1080 | |||
| 1081 | def asdict(obj, *, dict_factory=dict): |
||
| 1082 | """Return the fields of a dataclass instance as a new dictionary mapping |
||
| 1083 | field names to field values. |
||
| 1084 | |||
| 1085 | Example usage: |
||
| 1086 | |||
| 1087 | @dataclass |
||
| 1088 | class C: |
||
| 1089 | x: int |
||
| 1090 | y: int |
||
| 1091 | |||
| 1092 | c = C(1, 2) |
||
| 1093 | assert asdict(c) == {'x': 1, 'y': 2} |
||
| 1094 | |||
| 1095 | If given, 'dict_factory' will be used instead of built-in dict. |
||
| 1096 | The function applies recursively to field values that are |
||
| 1097 | dataclass instances. This will also look into built-in containers: |
||
| 1098 | tuples, lists, and dicts. |
||
| 1099 | """ |
||
| 1100 | if not _is_dataclass_instance(obj): |
||
| 1101 | raise TypeError("asdict() should be called on dataclass instances") |
||
| 1102 | return _asdict_inner(obj, dict_factory) |
||
| 1103 | |||
| 1104 | |||
| 1105 | View Code Duplication | def _asdict_inner(obj, dict_factory): |
|
|
|
|||
| 1106 | if _is_dataclass_instance(obj): |
||
| 1107 | result = [] |
||
| 1108 | for f in fields(obj): |
||
| 1109 | value = _asdict_inner(getattr(obj, f.name), dict_factory) |
||
| 1110 | result.append((f.name, value)) |
||
| 1111 | return dict_factory(result) |
||
| 1112 | if isinstance(obj, (list, tuple)): |
||
| 1113 | return type(obj)(_asdict_inner(v, dict_factory) for v in obj) |
||
| 1114 | if isinstance(obj, dict): |
||
| 1115 | return type(obj)( |
||
| 1116 | (_asdict_inner(k, dict_factory), _asdict_inner(v, dict_factory)) |
||
| 1117 | for k, v in obj.items() |
||
| 1118 | ) |
||
| 1119 | return copy.deepcopy(obj) |
||
| 1120 | |||
| 1121 | |||
| 1122 | def astuple(obj, *, tuple_factory=tuple): |
||
| 1123 | """Return the fields of a dataclass instance as a new tuple of field values. |
||
| 1124 | |||
| 1125 | Example usage:: |
||
| 1126 | |||
| 1127 | @dataclass |
||
| 1128 | class C: |
||
| 1129 | x: int |
||
| 1130 | y: int |
||
| 1131 | |||
| 1132 | c = C(1, 2) |
||
| 1133 | assert astuple(c) == (1, 2) |
||
| 1134 | |||
| 1135 | If given, 'tuple_factory' will be used instead of built-in tuple. |
||
| 1136 | The function applies recursively to field values that are |
||
| 1137 | dataclass instances. This will also look into built-in containers: |
||
| 1138 | tuples, lists, and dicts. |
||
| 1139 | """ |
||
| 1140 | |||
| 1141 | if not _is_dataclass_instance(obj): |
||
| 1142 | raise TypeError("astuple() should be called on dataclass instances") |
||
| 1143 | return _astuple_inner(obj, tuple_factory) |
||
| 1144 | |||
| 1145 | |||
| 1146 | View Code Duplication | def _astuple_inner(obj, tuple_factory): |
|
| 1147 | if _is_dataclass_instance(obj): |
||
| 1148 | result = [] |
||
| 1149 | for f in fields(obj): |
||
| 1150 | value = _astuple_inner(getattr(obj, f.name), tuple_factory) |
||
| 1151 | result.append(value) |
||
| 1152 | return tuple_factory(result) |
||
| 1153 | if isinstance(obj, (list, tuple)): |
||
| 1154 | return type(obj)(_astuple_inner(v, tuple_factory) for v in obj) |
||
| 1155 | if isinstance(obj, dict): |
||
| 1156 | return type(obj)( |
||
| 1157 | (_astuple_inner(k, tuple_factory), _astuple_inner(v, tuple_factory)) |
||
| 1158 | for k, v in obj.items() |
||
| 1159 | ) |
||
| 1160 | return copy.deepcopy(obj) |
||
| 1161 | |||
| 1162 | |||
| 1163 | def make_dataclass( |
||
| 1164 | cls_name, |
||
| 1165 | fields, |
||
| 1166 | *, |
||
| 1167 | bases=(), |
||
| 1168 | namespace=None, |
||
| 1169 | init=True, |
||
| 1170 | repr=True, |
||
| 1171 | eq=True, |
||
| 1172 | order=False, |
||
| 1173 | unsafe_hash=False, |
||
| 1174 | frozen=False, |
||
| 1175 | ): |
||
| 1176 | """Return a new dynamically created dataclass. |
||
| 1177 | |||
| 1178 | The dataclass name will be 'cls_name'. 'fields' is an iterable |
||
| 1179 | of either (name), (name, type) or (name, type, Field) objects. If type is |
||
| 1180 | omitted, use the string 'typing.Any'. Field objects are created by |
||
| 1181 | the equivalent of calling 'field(name, type [, Field-info])'. |
||
| 1182 | |||
| 1183 | C = make_dataclass('C', ['x', ('y', int), ('z', int, field(init=False))], bases=(Base,)) |
||
| 1184 | |||
| 1185 | is equivalent to: |
||
| 1186 | |||
| 1187 | @dataclass |
||
| 1188 | class C(Base): |
||
| 1189 | x: 'typing.Any' |
||
| 1190 | y: int |
||
| 1191 | z: int = field(init=False) |
||
| 1192 | |||
| 1193 | For the bases and namespace parameters, see the builtin type() function. |
||
| 1194 | |||
| 1195 | The parameters init, repr, eq, order, unsafe_hash, and frozen are passed to |
||
| 1196 | dataclass(). |
||
| 1197 | """ |
||
| 1198 | |||
| 1199 | if namespace is None: |
||
| 1200 | namespace = {} |
||
| 1201 | else: |
||
| 1202 | # Copy namespace since we're going to mutate it. |
||
| 1203 | namespace = namespace.copy() |
||
| 1204 | |||
| 1205 | # While we're looking through the field names, validate that they |
||
| 1206 | # are identifiers, are not keywords, and not duplicates. |
||
| 1207 | seen = set() |
||
| 1208 | anns = {} |
||
| 1209 | for item in fields: |
||
| 1210 | if isinstance(item, str): |
||
| 1211 | name = item |
||
| 1212 | tp = "typing.Any" |
||
| 1213 | elif len(item) == 2: |
||
| 1214 | ( |
||
| 1215 | name, |
||
| 1216 | tp, |
||
| 1217 | ) = item |
||
| 1218 | elif len(item) == 3: |
||
| 1219 | name, tp, spec = item |
||
| 1220 | namespace[name] = spec |
||
| 1221 | else: |
||
| 1222 | raise TypeError(f"Invalid field: {item!r}") |
||
| 1223 | |||
| 1224 | if not isinstance(name, str) or not name.isidentifier(): |
||
| 1225 | raise TypeError(f"Field names must be valid identifiers: {name!r}") |
||
| 1226 | if keyword.iskeyword(name): |
||
| 1227 | raise TypeError(f"Field names must not be keywords: {name!r}") |
||
| 1228 | if name in seen: |
||
| 1229 | raise TypeError(f"Field name duplicated: {name!r}") |
||
| 1230 | |||
| 1231 | seen.add(name) |
||
| 1232 | anns[name] = tp |
||
| 1233 | |||
| 1234 | namespace["__annotations__"] = anns |
||
| 1235 | # We use `types.new_class()` instead of simply `type()` to allow dynamic creation |
||
| 1236 | # of generic dataclassses. |
||
| 1237 | cls = types.new_class(cls_name, bases, {}, lambda ns: ns.update(namespace)) |
||
| 1238 | return dataclass( |
||
| 1239 | cls, |
||
| 1240 | init=init, |
||
| 1241 | repr=repr, |
||
| 1242 | eq=eq, |
||
| 1243 | order=order, |
||
| 1244 | unsafe_hash=unsafe_hash, |
||
| 1245 | frozen=frozen, |
||
| 1246 | ) |
||
| 1247 | |||
| 1248 | |||
| 1249 | def replace(obj, **changes): |
||
| 1250 | """Return a new object replacing specified fields with new values. |
||
| 1251 | |||
| 1252 | This is especially useful for frozen classes. Example usage: |
||
| 1253 | |||
| 1254 | @dataclass(frozen=True) |
||
| 1255 | class C: |
||
| 1256 | x: int |
||
| 1257 | y: int |
||
| 1258 | |||
| 1259 | c = C(1, 2) |
||
| 1260 | c1 = replace(c, x=3) |
||
| 1261 | assert c1.x == 3 and c1.y == 2 |
||
| 1262 | """ |
||
| 1263 | |||
| 1264 | # We're going to mutate 'changes', but that's okay because it's a |
||
| 1265 | # new dict, even if called with 'replace(obj, **my_changes)'. |
||
| 1266 | |||
| 1267 | if not _is_dataclass_instance(obj): |
||
| 1268 | raise TypeError("replace() should be called on dataclass instances") |
||
| 1269 | |||
| 1270 | # It's an error to have init=False fields in 'changes'. |
||
| 1271 | # If a field is not in 'changes', read its value from the provided obj. |
||
| 1272 | for f in getattr(obj, _FIELDS).values(): |
||
| 1273 | # Only consider normal fields or InitVars. |
||
| 1274 | # pylint: disable=protected-access |
||
| 1275 | if f._field_type is _FIELD_CLASSVAR: |
||
| 1276 | continue |
||
| 1277 | |||
| 1278 | if not f.init: |
||
| 1279 | # Error if this field is specified in changes. |
||
| 1280 | if f.name in changes: |
||
| 1281 | raise ValueError( |
||
| 1282 | f"field {f.name} is declared with " |
||
| 1283 | "init=False, it cannot be specified with " |
||
| 1284 | "replace()" |
||
| 1285 | ) |
||
| 1286 | continue |
||
| 1287 | |||
| 1288 | if f.name not in changes: |
||
| 1289 | # pylint: disable=protected-access |
||
| 1290 | if f._field_type is _FIELD_INITVAR: |
||
| 1291 | raise ValueError( |
||
| 1292 | f"InitVar {f.name!r} " "must be specified with replace()" |
||
| 1293 | ) |
||
| 1294 | changes[f.name] = getattr(obj, f.name) |
||
| 1295 | |||
| 1296 | # Create the new object, which calls __init__() and |
||
| 1297 | # __post_init__() (if defined), using all of the init fields we've |
||
| 1298 | # added and/or left in 'changes'. If there are values supplied in |
||
| 1299 | # changes that aren't fields, this will correctly raise a |
||
| 1300 | # TypeError. |
||
| 1301 | return obj.__class__(**changes) |
||
| 1302 |