summaryrefslogtreecommitdiff
path: root/astroid/brain/brain_builtin_inference.py
blob: e2455e54b031149ecb2e3625b8315f5f7c659ea2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
# Licensed under the LGPL: https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html
# For details: https://github.com/PyCQA/astroid/blob/main/LICENSE
# Copyright (c) https://github.com/PyCQA/astroid/blob/main/CONTRIBUTORS.txt

"""Astroid hooks for various builtins."""

from __future__ import annotations

import itertools
from collections.abc import Iterator
from functools import partial

from astroid import arguments, helpers, inference_tip, nodes, objects, util
from astroid.builder import AstroidBuilder
from astroid.context import InferenceContext
from astroid.exceptions import (
    AstroidTypeError,
    AttributeInferenceError,
    InferenceError,
    MroError,
    UseInferenceDefault,
)
from astroid.manager import AstroidManager
from astroid.nodes import scoped_nodes

OBJECT_DUNDER_NEW = "object.__new__"

STR_CLASS = """
class whatever(object):
    def join(self, iterable):
        return {rvalue}
    def replace(self, old, new, count=None):
        return {rvalue}
    def format(self, *args, **kwargs):
        return {rvalue}
    def encode(self, encoding='ascii', errors=None):
        return b''
    def decode(self, encoding='ascii', errors=None):
        return u''
    def capitalize(self):
        return {rvalue}
    def title(self):
        return {rvalue}
    def lower(self):
        return {rvalue}
    def upper(self):
        return {rvalue}
    def swapcase(self):
        return {rvalue}
    def index(self, sub, start=None, end=None):
        return 0
    def find(self, sub, start=None, end=None):
        return 0
    def count(self, sub, start=None, end=None):
        return 0
    def strip(self, chars=None):
        return {rvalue}
    def lstrip(self, chars=None):
        return {rvalue}
    def rstrip(self, chars=None):
        return {rvalue}
    def rjust(self, width, fillchar=None):
        return {rvalue}
    def center(self, width, fillchar=None):
        return {rvalue}
    def ljust(self, width, fillchar=None):
        return {rvalue}
"""


BYTES_CLASS = """
class whatever(object):
    def join(self, iterable):
        return {rvalue}
    def replace(self, old, new, count=None):
        return {rvalue}
    def decode(self, encoding='ascii', errors=None):
        return u''
    def capitalize(self):
        return {rvalue}
    def title(self):
        return {rvalue}
    def lower(self):
        return {rvalue}
    def upper(self):
        return {rvalue}
    def swapcase(self):
        return {rvalue}
    def index(self, sub, start=None, end=None):
        return 0
    def find(self, sub, start=None, end=None):
        return 0
    def count(self, sub, start=None, end=None):
        return 0
    def strip(self, chars=None):
        return {rvalue}
    def lstrip(self, chars=None):
        return {rvalue}
    def rstrip(self, chars=None):
        return {rvalue}
    def rjust(self, width, fillchar=None):
        return {rvalue}
    def center(self, width, fillchar=None):
        return {rvalue}
    def ljust(self, width, fillchar=None):
        return {rvalue}
"""


def _extend_string_class(class_node, code, rvalue):
    """function to extend builtin str/unicode class"""
    code = code.format(rvalue=rvalue)
    fake = AstroidBuilder(AstroidManager()).string_build(code)["whatever"]
    for method in fake.mymethods():
        method.parent = class_node
        method.lineno = None
        method.col_offset = None
        if "__class__" in method.locals:
            method.locals["__class__"] = [class_node]
        class_node.locals[method.name] = [method]
        method.parent = class_node


def _extend_builtins(class_transforms):
    builtin_ast = AstroidManager().builtins_module
    for class_name, transform in class_transforms.items():
        transform(builtin_ast[class_name])


_extend_builtins(
    {
        "bytes": partial(_extend_string_class, code=BYTES_CLASS, rvalue="b''"),
        "str": partial(_extend_string_class, code=STR_CLASS, rvalue="''"),
    }
)


def _builtin_filter_predicate(node, builtin_name) -> bool:
    if (
        builtin_name == "type"
        and node.root().name == "re"
        and isinstance(node.func, nodes.Name)
        and node.func.name == "type"
        and isinstance(node.parent, nodes.Assign)
        and len(node.parent.targets) == 1
        and isinstance(node.parent.targets[0], nodes.AssignName)
        and node.parent.targets[0].name in {"Pattern", "Match"}
    ):
        # Handle re.Pattern and re.Match in brain_re
        # Match these patterns from stdlib/re.py
        # ```py
        # Pattern = type(...)
        # Match = type(...)
        # ```
        return False
    if isinstance(node.func, nodes.Name) and node.func.name == builtin_name:
        return True
    if isinstance(node.func, nodes.Attribute):
        return (
            node.func.attrname == "fromkeys"
            and isinstance(node.func.expr, nodes.Name)
            and node.func.expr.name == "dict"
        )
    return False


def register_builtin_transform(transform, builtin_name):
    """Register a new transform function for the given *builtin_name*.

    The transform function must accept two parameters, a node and
    an optional context.
    """

    def _transform_wrapper(node, context: InferenceContext | None = None):
        result = transform(node, context=context)
        if result:
            if not result.parent:
                # Let the transformation function determine
                # the parent for its result. Otherwise,
                # we set it to be the node we transformed from.
                result.parent = node

            if result.lineno is None:
                result.lineno = node.lineno
            # Can be a 'Module' see https://github.com/PyCQA/pylint/issues/4671
            # We don't have a regression test on this one: tread carefully
            if hasattr(result, "col_offset") and result.col_offset is None:
                result.col_offset = node.col_offset
        return iter([result])

    AstroidManager().register_transform(
        nodes.Call,
        inference_tip(_transform_wrapper),
        partial(_builtin_filter_predicate, builtin_name=builtin_name),
    )


def _container_generic_inference(node, context, node_type, transform):
    args = node.args
    if not args:
        return node_type()
    if len(node.args) > 1:
        raise UseInferenceDefault()

    (arg,) = args
    transformed = transform(arg)
    if not transformed:
        try:
            inferred = next(arg.infer(context=context))
        except (InferenceError, StopIteration) as exc:
            raise UseInferenceDefault from exc
        if inferred is util.Uninferable:
            raise UseInferenceDefault
        transformed = transform(inferred)
    if not transformed or transformed is util.Uninferable:
        raise UseInferenceDefault
    return transformed


def _container_generic_transform(  # pylint: disable=inconsistent-return-statements
    arg, context, klass, iterables, build_elts
):
    if isinstance(arg, klass):
        return arg
    if isinstance(arg, iterables):
        if all(isinstance(elt, nodes.Const) for elt in arg.elts):
            elts = [elt.value for elt in arg.elts]
        else:
            # TODO: Does not handle deduplication for sets.
            elts = []
            for element in arg.elts:
                if not element:
                    continue
                inferred = helpers.safe_infer(element, context=context)
                if inferred:
                    evaluated_object = nodes.EvaluatedObject(
                        original=element, value=inferred
                    )
                    elts.append(evaluated_object)
    elif isinstance(arg, nodes.Dict):
        # Dicts need to have consts as strings already.
        if not all(isinstance(elt[0], nodes.Const) for elt in arg.items):
            raise UseInferenceDefault()
        elts = [item[0].value for item in arg.items]
    elif isinstance(arg, nodes.Const) and isinstance(arg.value, (str, bytes)):
        elts = arg.value
    else:
        return
    return klass.from_elements(elts=build_elts(elts))


def _infer_builtin_container(
    node, context, klass=None, iterables=None, build_elts=None
):
    transform_func = partial(
        _container_generic_transform,
        context=context,
        klass=klass,
        iterables=iterables,
        build_elts=build_elts,
    )

    return _container_generic_inference(node, context, klass, transform_func)


# pylint: disable=invalid-name
infer_tuple = partial(
    _infer_builtin_container,
    klass=nodes.Tuple,
    iterables=(
        nodes.List,
        nodes.Set,
        objects.FrozenSet,
        objects.DictItems,
        objects.DictKeys,
        objects.DictValues,
    ),
    build_elts=tuple,
)

infer_list = partial(
    _infer_builtin_container,
    klass=nodes.List,
    iterables=(
        nodes.Tuple,
        nodes.Set,
        objects.FrozenSet,
        objects.DictItems,
        objects.DictKeys,
        objects.DictValues,
    ),
    build_elts=list,
)

infer_set = partial(
    _infer_builtin_container,
    klass=nodes.Set,
    iterables=(nodes.List, nodes.Tuple, objects.FrozenSet, objects.DictKeys),
    build_elts=set,
)

infer_frozenset = partial(
    _infer_builtin_container,
    klass=objects.FrozenSet,
    iterables=(nodes.List, nodes.Tuple, nodes.Set, objects.FrozenSet, objects.DictKeys),
    build_elts=frozenset,
)


def _get_elts(arg, context):
    def is_iterable(n):
        return isinstance(n, (nodes.List, nodes.Tuple, nodes.Set))

    try:
        inferred = next(arg.infer(context))
    except (InferenceError, StopIteration) as exc:
        raise UseInferenceDefault from exc
    if isinstance(inferred, nodes.Dict):
        items = inferred.items
    elif is_iterable(inferred):
        items = []
        for elt in inferred.elts:
            # If an item is not a pair of two items,
            # then fallback to the default inference.
            # Also, take in consideration only hashable items,
            # tuples and consts. We are choosing Names as well.
            if not is_iterable(elt):
                raise UseInferenceDefault()
            if len(elt.elts) != 2:
                raise UseInferenceDefault()
            if not isinstance(elt.elts[0], (nodes.Tuple, nodes.Const, nodes.Name)):
                raise UseInferenceDefault()
            items.append(tuple(elt.elts))
    else:
        raise UseInferenceDefault()
    return items


def infer_dict(node, context: InferenceContext | None = None):
    """Try to infer a dict call to a Dict node.

    The function treats the following cases:

        * dict()
        * dict(mapping)
        * dict(iterable)
        * dict(iterable, **kwargs)
        * dict(mapping, **kwargs)
        * dict(**kwargs)

    If a case can't be inferred, we'll fallback to default inference.
    """
    call = arguments.CallSite.from_call(node, context=context)
    if call.has_invalid_arguments() or call.has_invalid_keywords():
        raise UseInferenceDefault

    args = call.positional_arguments
    kwargs = list(call.keyword_arguments.items())

    if not args and not kwargs:
        # dict()
        return nodes.Dict()
    if kwargs and not args:
        # dict(a=1, b=2, c=4)
        items = [(nodes.Const(key), value) for key, value in kwargs]
    elif len(args) == 1 and kwargs:
        # dict(some_iterable, b=2, c=4)
        elts = _get_elts(args[0], context)
        keys = [(nodes.Const(key), value) for key, value in kwargs]
        items = elts + keys
    elif len(args) == 1:
        items = _get_elts(args[0], context)
    else:
        raise UseInferenceDefault()
    value = nodes.Dict(
        col_offset=node.col_offset, lineno=node.lineno, parent=node.parent
    )
    value.postinit(items)
    return value


def infer_super(node, context: InferenceContext | None = None):
    """Understand super calls.

    There are some restrictions for what can be understood:

        * unbounded super (one argument form) is not understood.

        * if the super call is not inside a function (classmethod or method),
          then the default inference will be used.

        * if the super arguments can't be inferred, the default inference
          will be used.
    """
    if len(node.args) == 1:
        # Ignore unbounded super.
        raise UseInferenceDefault

    scope = node.scope()
    if not isinstance(scope, nodes.FunctionDef):
        # Ignore non-method uses of super.
        raise UseInferenceDefault
    if scope.type not in ("classmethod", "method"):
        # Not interested in staticmethods.
        raise UseInferenceDefault

    cls = scoped_nodes.get_wrapping_class(scope)
    if not node.args:
        mro_pointer = cls
        # In we are in a classmethod, the interpreter will fill
        # automatically the class as the second argument, not an instance.
        if scope.type == "classmethod":
            mro_type = cls
        else:
            mro_type = cls.instantiate_class()
    else:
        try:
            mro_pointer = next(node.args[0].infer(context=context))
        except (InferenceError, StopIteration) as exc:
            raise UseInferenceDefault from exc
        try:
            mro_type = next(node.args[1].infer(context=context))
        except (InferenceError, StopIteration) as exc:
            raise UseInferenceDefault from exc

    if mro_pointer is util.Uninferable or mro_type is util.Uninferable:
        # No way we could understand this.
        raise UseInferenceDefault

    super_obj = objects.Super(
        mro_pointer=mro_pointer, mro_type=mro_type, self_class=cls, scope=scope
    )
    super_obj.parent = node
    return super_obj


def _infer_getattr_args(node, context):
    if len(node.args) not in (2, 3):
        # Not a valid getattr call.
        raise UseInferenceDefault

    try:
        obj = next(node.args[0].infer(context=context))
        attr = next(node.args[1].infer(context=context))
    except (InferenceError, StopIteration) as exc:
        raise UseInferenceDefault from exc

    if obj is util.Uninferable or attr is util.Uninferable:
        # If one of the arguments is something we can't infer,
        # then also make the result of the getattr call something
        # which is unknown.
        return util.Uninferable, util.Uninferable

    is_string = isinstance(attr, nodes.Const) and isinstance(attr.value, str)
    if not is_string:
        raise UseInferenceDefault

    return obj, attr.value


def infer_getattr(node, context: InferenceContext | None = None):
    """Understand getattr calls

    If one of the arguments is an Uninferable object, then the
    result will be an Uninferable object. Otherwise, the normal attribute
    lookup will be done.
    """
    obj, attr = _infer_getattr_args(node, context)
    if (
        obj is util.Uninferable
        or attr is util.Uninferable
        or not hasattr(obj, "igetattr")
    ):
        return util.Uninferable

    try:
        return next(obj.igetattr(attr, context=context))
    except (StopIteration, InferenceError, AttributeInferenceError):
        if len(node.args) == 3:
            # Try to infer the default and return it instead.
            try:
                return next(node.args[2].infer(context=context))
            except (StopIteration, InferenceError) as exc:
                raise UseInferenceDefault from exc

    raise UseInferenceDefault


def infer_hasattr(node, context: InferenceContext | None = None):
    """Understand hasattr calls

    This always guarantees three possible outcomes for calling
    hasattr: Const(False) when we are sure that the object
    doesn't have the intended attribute, Const(True) when
    we know that the object has the attribute and Uninferable
    when we are unsure of the outcome of the function call.
    """
    try:
        obj, attr = _infer_getattr_args(node, context)
        if (
            obj is util.Uninferable
            or attr is util.Uninferable
            or not hasattr(obj, "getattr")
        ):
            return util.Uninferable
        obj.getattr(attr, context=context)
    except UseInferenceDefault:
        # Can't infer something from this function call.
        return util.Uninferable
    except AttributeInferenceError:
        # Doesn't have it.
        return nodes.Const(False)
    return nodes.Const(True)


def infer_callable(node, context: InferenceContext | None = None):
    """Understand callable calls

    This follows Python's semantics, where an object
    is callable if it provides an attribute __call__,
    even though that attribute is something which can't be
    called.
    """
    if len(node.args) != 1:
        # Invalid callable call.
        raise UseInferenceDefault

    argument = node.args[0]
    try:
        inferred = next(argument.infer(context=context))
    except (InferenceError, StopIteration):
        return util.Uninferable
    if inferred is util.Uninferable:
        return util.Uninferable
    return nodes.Const(inferred.callable())


def infer_property(
    node: nodes.Call, context: InferenceContext | None = None
) -> objects.Property:
    """Understand `property` class

    This only infers the output of `property`
    call, not the arguments themselves.
    """
    if len(node.args) < 1:
        # Invalid property call.
        raise UseInferenceDefault

    getter = node.args[0]
    try:
        inferred = next(getter.infer(context=context))
    except (InferenceError, StopIteration) as exc:
        raise UseInferenceDefault from exc

    if not isinstance(inferred, (nodes.FunctionDef, nodes.Lambda)):
        raise UseInferenceDefault

    prop_func = objects.Property(
        function=inferred,
        name=inferred.name,
        lineno=node.lineno,
        parent=node,
        col_offset=node.col_offset,
    )
    prop_func.postinit(
        body=[],
        args=inferred.args,
        doc_node=getattr(inferred, "doc_node", None),
    )
    return prop_func


def infer_bool(node, context: InferenceContext | None = None):
    """Understand bool calls."""
    if len(node.args) > 1:
        # Invalid bool call.
        raise UseInferenceDefault

    if not node.args:
        return nodes.Const(False)

    argument = node.args[0]
    try:
        inferred = next(argument.infer(context=context))
    except (InferenceError, StopIteration):
        return util.Uninferable
    if inferred is util.Uninferable:
        return util.Uninferable

    bool_value = inferred.bool_value(context=context)
    if bool_value is util.Uninferable:
        return util.Uninferable
    return nodes.Const(bool_value)


def infer_type(node, context: InferenceContext | None = None):
    """Understand the one-argument form of *type*."""
    if len(node.args) != 1:
        raise UseInferenceDefault

    return helpers.object_type(node.args[0], context)


def infer_slice(node, context: InferenceContext | None = None):
    """Understand `slice` calls."""
    args = node.args
    if not 0 < len(args) <= 3:
        raise UseInferenceDefault

    infer_func = partial(helpers.safe_infer, context=context)
    args = [infer_func(arg) for arg in args]
    for arg in args:
        if not arg or arg is util.Uninferable:
            raise UseInferenceDefault
        if not isinstance(arg, nodes.Const):
            raise UseInferenceDefault
        if not isinstance(arg.value, (type(None), int)):
            raise UseInferenceDefault

    if len(args) < 3:
        # Make sure we have 3 arguments.
        args.extend([None] * (3 - len(args)))

    slice_node = nodes.Slice(
        lineno=node.lineno, col_offset=node.col_offset, parent=node.parent
    )
    slice_node.postinit(*args)
    return slice_node


def _infer_object__new__decorator(node, context: InferenceContext | None = None):
    # Instantiate class immediately
    # since that's what @object.__new__ does
    return iter((node.instantiate_class(),))


def _infer_object__new__decorator_check(node) -> bool:
    """Predicate before inference_tip

    Check if the given ClassDef has an @object.__new__ decorator
    """
    if not node.decorators:
        return False

    for decorator in node.decorators.nodes:
        if isinstance(decorator, nodes.Attribute):
            if decorator.as_string() == OBJECT_DUNDER_NEW:
                return True
    return False


def infer_issubclass(callnode, context: InferenceContext | None = None):
    """Infer issubclass() calls

    :param nodes.Call callnode: an `issubclass` call
    :param InferenceContext context: the context for the inference
    :rtype nodes.Const: Boolean Const value of the `issubclass` call
    :raises UseInferenceDefault: If the node cannot be inferred
    """
    call = arguments.CallSite.from_call(callnode, context=context)
    if call.keyword_arguments:
        # issubclass doesn't support keyword arguments
        raise UseInferenceDefault("TypeError: issubclass() takes no keyword arguments")
    if len(call.positional_arguments) != 2:
        raise UseInferenceDefault(
            f"Expected two arguments, got {len(call.positional_arguments)}"
        )
    # The left hand argument is the obj to be checked
    obj_node, class_or_tuple_node = call.positional_arguments

    try:
        obj_type = next(obj_node.infer(context=context))
    except (InferenceError, StopIteration) as exc:
        raise UseInferenceDefault from exc
    if not isinstance(obj_type, nodes.ClassDef):
        raise UseInferenceDefault("TypeError: arg 1 must be class")

    # The right hand argument is the class(es) that the given
    # object is to be checked against.
    try:
        class_container = _class_or_tuple_to_container(
            class_or_tuple_node, context=context
        )
    except InferenceError as exc:
        raise UseInferenceDefault from exc
    try:
        issubclass_bool = helpers.object_issubclass(obj_type, class_container, context)
    except AstroidTypeError as exc:
        raise UseInferenceDefault("TypeError: " + str(exc)) from exc
    except MroError as exc:
        raise UseInferenceDefault from exc
    return nodes.Const(issubclass_bool)


def infer_isinstance(callnode, context: InferenceContext | None = None):
    """Infer isinstance calls

    :param nodes.Call callnode: an isinstance call
    :rtype nodes.Const: Boolean Const value of isinstance call

    :raises UseInferenceDefault: If the node cannot be inferred
    """
    call = arguments.CallSite.from_call(callnode, context=context)
    if call.keyword_arguments:
        # isinstance doesn't support keyword arguments
        raise UseInferenceDefault("TypeError: isinstance() takes no keyword arguments")
    if len(call.positional_arguments) != 2:
        raise UseInferenceDefault(
            f"Expected two arguments, got {len(call.positional_arguments)}"
        )
    # The left hand argument is the obj to be checked
    obj_node, class_or_tuple_node = call.positional_arguments
    # The right hand argument is the class(es) that the given
    # obj is to be check is an instance of
    try:
        class_container = _class_or_tuple_to_container(
            class_or_tuple_node, context=context
        )
    except InferenceError as exc:
        raise UseInferenceDefault from exc
    try:
        isinstance_bool = helpers.object_isinstance(obj_node, class_container, context)
    except AstroidTypeError as exc:
        raise UseInferenceDefault("TypeError: " + str(exc)) from exc
    except MroError as exc:
        raise UseInferenceDefault from exc
    if isinstance_bool is util.Uninferable:
        raise UseInferenceDefault
    return nodes.Const(isinstance_bool)


def _class_or_tuple_to_container(node, context: InferenceContext | None = None):
    # Move inferences results into container
    # to simplify later logic
    # raises InferenceError if any of the inferences fall through
    try:
        node_infer = next(node.infer(context=context))
    except StopIteration as e:
        raise InferenceError(node=node, context=context) from e
    # arg2 MUST be a type or a TUPLE of types
    # for isinstance
    if isinstance(node_infer, nodes.Tuple):
        try:
            class_container = [
                next(node.infer(context=context)) for node in node_infer.elts
            ]
        except StopIteration as e:
            raise InferenceError(node=node, context=context) from e
        class_container = [
            klass_node for klass_node in class_container if klass_node is not None
        ]
    else:
        class_container = [node_infer]
    return class_container


def infer_len(node, context: InferenceContext | None = None):
    """Infer length calls

    :param nodes.Call node: len call to infer
    :param context.InferenceContext: node context
    :rtype nodes.Const: a Const node with the inferred length, if possible
    """
    call = arguments.CallSite.from_call(node, context=context)
    if call.keyword_arguments:
        raise UseInferenceDefault("TypeError: len() must take no keyword arguments")
    if len(call.positional_arguments) != 1:
        raise UseInferenceDefault(
            "TypeError: len() must take exactly one argument "
            "({len}) given".format(len=len(call.positional_arguments))
        )
    [argument_node] = call.positional_arguments

    try:
        return nodes.Const(helpers.object_len(argument_node, context=context))
    except (AstroidTypeError, InferenceError) as exc:
        raise UseInferenceDefault(str(exc)) from exc


def infer_str(node, context: InferenceContext | None = None):
    """Infer str() calls

    :param nodes.Call node: str() call to infer
    :param context.InferenceContext: node context
    :rtype nodes.Const: a Const containing an empty string
    """
    call = arguments.CallSite.from_call(node, context=context)
    if call.keyword_arguments:
        raise UseInferenceDefault("TypeError: str() must take no keyword arguments")
    try:
        return nodes.Const("")
    except (AstroidTypeError, InferenceError) as exc:
        raise UseInferenceDefault(str(exc)) from exc


def infer_int(node, context: InferenceContext | None = None):
    """Infer int() calls

    :param nodes.Call node: int() call to infer
    :param context.InferenceContext: node context
    :rtype nodes.Const: a Const containing the integer value of the int() call
    """
    call = arguments.CallSite.from_call(node, context=context)
    if call.keyword_arguments:
        raise UseInferenceDefault("TypeError: int() must take no keyword arguments")

    if call.positional_arguments:
        try:
            first_value = next(call.positional_arguments[0].infer(context=context))
        except (InferenceError, StopIteration) as exc:
            raise UseInferenceDefault(str(exc)) from exc

        if first_value is util.Uninferable:
            raise UseInferenceDefault

        if isinstance(first_value, nodes.Const) and isinstance(
            first_value.value, (int, str)
        ):
            try:
                actual_value = int(first_value.value)
            except ValueError:
                return nodes.Const(0)
            return nodes.Const(actual_value)

    return nodes.Const(0)


def infer_dict_fromkeys(node, context: InferenceContext | None = None):
    """Infer dict.fromkeys

    :param nodes.Call node: dict.fromkeys() call to infer
    :param context.InferenceContext context: node context
    :rtype nodes.Dict:
        a Dictionary containing the values that astroid was able to infer.
        In case the inference failed for any reason, an empty dictionary
        will be inferred instead.
    """

    def _build_dict_with_elements(elements):
        new_node = nodes.Dict(
            col_offset=node.col_offset, lineno=node.lineno, parent=node.parent
        )
        new_node.postinit(elements)
        return new_node

    call = arguments.CallSite.from_call(node, context=context)
    if call.keyword_arguments:
        raise UseInferenceDefault("TypeError: int() must take no keyword arguments")
    if len(call.positional_arguments) not in {1, 2}:
        raise UseInferenceDefault(
            "TypeError: Needs between 1 and 2 positional arguments"
        )

    default = nodes.Const(None)
    values = call.positional_arguments[0]
    try:
        inferred_values = next(values.infer(context=context))
    except (InferenceError, StopIteration):
        return _build_dict_with_elements([])
    if inferred_values is util.Uninferable:
        return _build_dict_with_elements([])

    # Limit to a couple of potential values, as this can become pretty complicated
    accepted_iterable_elements = (nodes.Const,)
    if isinstance(inferred_values, (nodes.List, nodes.Set, nodes.Tuple)):
        elements = inferred_values.elts
        for element in elements:
            if not isinstance(element, accepted_iterable_elements):
                # Fallback to an empty dict
                return _build_dict_with_elements([])

        elements_with_value = [(element, default) for element in elements]
        return _build_dict_with_elements(elements_with_value)
    if isinstance(inferred_values, nodes.Const) and isinstance(
        inferred_values.value, (str, bytes)
    ):
        elements = [
            (nodes.Const(element), default) for element in inferred_values.value
        ]
        return _build_dict_with_elements(elements)
    if isinstance(inferred_values, nodes.Dict):
        keys = inferred_values.itered()
        for key in keys:
            if not isinstance(key, accepted_iterable_elements):
                # Fallback to an empty dict
                return _build_dict_with_elements([])

        elements_with_value = [(element, default) for element in keys]
        return _build_dict_with_elements(elements_with_value)

    # Fallback to an empty dictionary
    return _build_dict_with_elements([])


def _infer_copy_method(
    node: nodes.Call, context: InferenceContext | None = None
) -> Iterator[nodes.NodeNG]:
    assert isinstance(node.func, nodes.Attribute)
    inferred_orig, inferred_copy = itertools.tee(node.func.expr.infer(context=context))
    if all(
        isinstance(
            inferred_node, (nodes.Dict, nodes.List, nodes.Set, objects.FrozenSet)
        )
        for inferred_node in inferred_orig
    ):
        return inferred_copy

    raise UseInferenceDefault()


def _is_str_format_call(node: nodes.Call) -> bool:
    """Catch calls to str.format()."""
    if not isinstance(node.func, nodes.Attribute) or not node.func.attrname == "format":
        return False

    if isinstance(node.func.expr, nodes.Name):
        value = helpers.safe_infer(node.func.expr)
    else:
        value = node.func.expr

    return isinstance(value, nodes.Const) and isinstance(value.value, str)


def _infer_str_format_call(
    node: nodes.Call, context: InferenceContext | None = None
) -> Iterator[nodes.Const | type[util.Uninferable]]:
    """Return a Const node based on the template and passed arguments."""
    call = arguments.CallSite.from_call(node, context=context)
    if isinstance(node.func.expr, nodes.Name):
        value: nodes.Const = helpers.safe_infer(node.func.expr)
    else:
        value = node.func.expr

    format_template = value.value

    # Get the positional arguments passed
    inferred_positional = [
        helpers.safe_infer(i, context) for i in call.positional_arguments
    ]
    if not all(isinstance(i, nodes.Const) for i in inferred_positional):
        return iter([util.Uninferable])
    pos_values: list[str] = [i.value for i in inferred_positional]

    # Get the keyword arguments passed
    inferred_keyword = {
        k: helpers.safe_infer(v, context) for k, v in call.keyword_arguments.items()
    }
    if not all(isinstance(i, nodes.Const) for i in inferred_keyword.values()):
        return iter([util.Uninferable])
    keyword_values: dict[str, str] = {k: v.value for k, v in inferred_keyword.items()}

    try:
        formatted_string = format_template.format(*pos_values, **keyword_values)
    except (IndexError, KeyError, TypeError, ValueError):
        # IndexError: there are too few arguments to interpolate
        # TypeError: Unsupported format string
        # ValueError: Unknown format code
        return iter([util.Uninferable])

    return iter([nodes.const_factory(formatted_string)])


# Builtins inference
register_builtin_transform(infer_bool, "bool")
register_builtin_transform(infer_super, "super")
register_builtin_transform(infer_callable, "callable")
register_builtin_transform(infer_property, "property")
register_builtin_transform(infer_getattr, "getattr")
register_builtin_transform(infer_hasattr, "hasattr")
register_builtin_transform(infer_tuple, "tuple")
register_builtin_transform(infer_set, "set")
register_builtin_transform(infer_list, "list")
register_builtin_transform(infer_dict, "dict")
register_builtin_transform(infer_frozenset, "frozenset")
register_builtin_transform(infer_type, "type")
register_builtin_transform(infer_slice, "slice")
register_builtin_transform(infer_isinstance, "isinstance")
register_builtin_transform(infer_issubclass, "issubclass")
register_builtin_transform(infer_len, "len")
register_builtin_transform(infer_str, "str")
register_builtin_transform(infer_int, "int")
register_builtin_transform(infer_dict_fromkeys, "dict.fromkeys")


# Infer object.__new__ calls
AstroidManager().register_transform(
    nodes.ClassDef,
    inference_tip(_infer_object__new__decorator),
    _infer_object__new__decorator_check,
)

AstroidManager().register_transform(
    nodes.Call,
    inference_tip(_infer_copy_method),
    lambda node: isinstance(node.func, nodes.Attribute)
    and node.func.attrname == "copy",
)

AstroidManager().register_transform(
    nodes.Call, inference_tip(_infer_str_format_call), _is_str_format_call
)