master
/ miniconda3 / lib / python3.11 / site-packages / packaging / specifiers.py

specifiers.py @74036c5

41a0142
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   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
1003
1004
1005
# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
"""
.. testsetup::

    from packaging.specifiers import Specifier, SpecifierSet, InvalidSpecifier
    from packaging.version import Version
"""

import abc
import itertools
import re
from typing import (
    Callable,
    Iterable,
    Iterator,
    List,
    Optional,
    Set,
    Tuple,
    TypeVar,
    Union,
)

from .utils import canonicalize_version
from .version import Version

UnparsedVersion = Union[Version, str]
UnparsedVersionVar = TypeVar("UnparsedVersionVar", bound=UnparsedVersion)
CallableOperator = Callable[[Version, str], bool]


def _coerce_version(version: UnparsedVersion) -> Version:
    if not isinstance(version, Version):
        version = Version(version)
    return version


class InvalidSpecifier(ValueError):
    """
    Raised when attempting to create a :class:`Specifier` with a specifier
    string that is invalid.

    >>> Specifier("lolwat")
    Traceback (most recent call last):
        ...
    packaging.specifiers.InvalidSpecifier: Invalid specifier: 'lolwat'
    """


class BaseSpecifier(metaclass=abc.ABCMeta):
    @abc.abstractmethod
    def __str__(self) -> str:
        """
        Returns the str representation of this Specifier-like object. This
        should be representative of the Specifier itself.
        """

    @abc.abstractmethod
    def __hash__(self) -> int:
        """
        Returns a hash value for this Specifier-like object.
        """

    @abc.abstractmethod
    def __eq__(self, other: object) -> bool:
        """
        Returns a boolean representing whether or not the two Specifier-like
        objects are equal.

        :param other: The other object to check against.
        """

    @property
    @abc.abstractmethod
    def prereleases(self) -> Optional[bool]:
        """Whether or not pre-releases as a whole are allowed.

        This can be set to either ``True`` or ``False`` to explicitly enable or disable
        prereleases or it can be set to ``None`` (the default) to use default semantics.
        """

    @prereleases.setter
    def prereleases(self, value: bool) -> None:
        """Setter for :attr:`prereleases`.

        :param value: The value to set.
        """

    @abc.abstractmethod
    def contains(self, item: str, prereleases: Optional[bool] = None) -> bool:
        """
        Determines if the given item is contained within this specifier.
        """

    @abc.abstractmethod
    def filter(
        self, iterable: Iterable[UnparsedVersionVar], prereleases: Optional[bool] = None
    ) -> Iterator[UnparsedVersionVar]:
        """
        Takes an iterable of items and filters them so that only items which
        are contained within this specifier are allowed in it.
        """


class Specifier(BaseSpecifier):
    """This class abstracts handling of version specifiers.

    .. tip::

        It is generally not required to instantiate this manually. You should instead
        prefer to work with :class:`SpecifierSet` instead, which can parse
        comma-separated version specifiers (which is what package metadata contains).
    """

    _operator_regex_str = r"""
        (?P<operator>(~=|==|!=|<=|>=|<|>|===))
        """
    _version_regex_str = r"""
        (?P<version>
            (?:
                # The identity operators allow for an escape hatch that will
                # do an exact string match of the version you wish to install.
                # This will not be parsed by PEP 440 and we cannot determine
                # any semantic meaning from it. This operator is discouraged
                # but included entirely as an escape hatch.
                (?<====)  # Only match for the identity operator
                \s*
                [^\s;)]*  # The arbitrary version can be just about anything,
                          # we match everything except for whitespace, a
                          # semi-colon for marker support, and a closing paren
                          # since versions can be enclosed in them.
            )
            |
            (?:
                # The (non)equality operators allow for wild card and local
                # versions to be specified so we have to define these two
                # operators separately to enable that.
                (?<===|!=)            # Only match for equals and not equals

                \s*
                v?
                (?:[0-9]+!)?          # epoch
                [0-9]+(?:\.[0-9]+)*   # release

                # You cannot use a wild card and a pre-release, post-release, a dev or
                # local version together so group them with a | and make them optional.
                (?:
                    \.\*  # Wild card syntax of .*
                    |
                    (?:                                  # pre release
                        [-_\.]?
                        (alpha|beta|preview|pre|a|b|c|rc)
                        [-_\.]?
                        [0-9]*
                    )?
                    (?:                                  # post release
                        (?:-[0-9]+)|(?:[-_\.]?(post|rev|r)[-_\.]?[0-9]*)
                    )?
                    (?:[-_\.]?dev[-_\.]?[0-9]*)?         # dev release
                    (?:\+[a-z0-9]+(?:[-_\.][a-z0-9]+)*)? # local
                )?
            )
            |
            (?:
                # The compatible operator requires at least two digits in the
                # release segment.
                (?<=~=)               # Only match for the compatible operator

                \s*
                v?
                (?:[0-9]+!)?          # epoch
                [0-9]+(?:\.[0-9]+)+   # release  (We have a + instead of a *)
                (?:                   # pre release
                    [-_\.]?
                    (alpha|beta|preview|pre|a|b|c|rc)
                    [-_\.]?
                    [0-9]*
                )?
                (?:                                   # post release
                    (?:-[0-9]+)|(?:[-_\.]?(post|rev|r)[-_\.]?[0-9]*)
                )?
                (?:[-_\.]?dev[-_\.]?[0-9]*)?          # dev release
            )
            |
            (?:
                # All other operators only allow a sub set of what the
                # (non)equality operators do. Specifically they do not allow
                # local versions to be specified nor do they allow the prefix
                # matching wild cards.
                (?<!==|!=|~=)         # We have special cases for these
                                      # operators so we want to make sure they
                                      # don't match here.

                \s*
                v?
                (?:[0-9]+!)?          # epoch
                [0-9]+(?:\.[0-9]+)*   # release
                (?:                   # pre release
                    [-_\.]?
                    (alpha|beta|preview|pre|a|b|c|rc)
                    [-_\.]?
                    [0-9]*
                )?
                (?:                                   # post release
                    (?:-[0-9]+)|(?:[-_\.]?(post|rev|r)[-_\.]?[0-9]*)
                )?
                (?:[-_\.]?dev[-_\.]?[0-9]*)?          # dev release
            )
        )
        """

    _regex = re.compile(
        r"^\s*" + _operator_regex_str + _version_regex_str + r"\s*$",
        re.VERBOSE | re.IGNORECASE,
    )

    _operators = {
        "~=": "compatible",
        "==": "equal",
        "!=": "not_equal",
        "<=": "less_than_equal",
        ">=": "greater_than_equal",
        "<": "less_than",
        ">": "greater_than",
        "===": "arbitrary",
    }

    def __init__(self, spec: str = "", prereleases: Optional[bool] = None) -> None:
        """Initialize a Specifier instance.

        :param spec:
            The string representation of a specifier which will be parsed and
            normalized before use.
        :param prereleases:
            This tells the specifier if it should accept prerelease versions if
            applicable or not. The default of ``None`` will autodetect it from the
            given specifiers.
        :raises InvalidSpecifier:
            If the given specifier is invalid (i.e. bad syntax).
        """
        match = self._regex.search(spec)
        if not match:
            raise InvalidSpecifier(f"Invalid specifier: '{spec}'")

        self._spec: Tuple[str, str] = (
            match.group("operator").strip(),
            match.group("version").strip(),
        )

        # Store whether or not this Specifier should accept prereleases
        self._prereleases = prereleases

    @property
    def prereleases(self) -> bool:
        # If there is an explicit prereleases set for this, then we'll just
        # blindly use that.
        if self._prereleases is not None:
            return self._prereleases

        # Look at all of our specifiers and determine if they are inclusive
        # operators, and if they are if they are including an explicit
        # prerelease.
        operator, version = self._spec
        if operator in ["==", ">=", "<=", "~=", "==="]:
            # The == specifier can include a trailing .*, if it does we
            # want to remove before parsing.
            if operator == "==" and version.endswith(".*"):
                version = version[:-2]

            # Parse the version, and if it is a pre-release than this
            # specifier allows pre-releases.
            if Version(version).is_prerelease:
                return True

        return False

    @prereleases.setter
    def prereleases(self, value: bool) -> None:
        self._prereleases = value

    @property
    def operator(self) -> str:
        """The operator of this specifier.

        >>> Specifier("==1.2.3").operator
        '=='
        """
        return self._spec[0]

    @property
    def version(self) -> str:
        """The version of this specifier.

        >>> Specifier("==1.2.3").version
        '1.2.3'
        """
        return self._spec[1]

    def __repr__(self) -> str:
        """A representation of the Specifier that shows all internal state.

        >>> Specifier('>=1.0.0')
        <Specifier('>=1.0.0')>
        >>> Specifier('>=1.0.0', prereleases=False)
        <Specifier('>=1.0.0', prereleases=False)>
        >>> Specifier('>=1.0.0', prereleases=True)
        <Specifier('>=1.0.0', prereleases=True)>
        """
        pre = (
            f", prereleases={self.prereleases!r}"
            if self._prereleases is not None
            else ""
        )

        return f"<{self.__class__.__name__}({str(self)!r}{pre})>"

    def __str__(self) -> str:
        """A string representation of the Specifier that can be round-tripped.

        >>> str(Specifier('>=1.0.0'))
        '>=1.0.0'
        >>> str(Specifier('>=1.0.0', prereleases=False))
        '>=1.0.0'
        """
        return "{}{}".format(*self._spec)

    @property
    def _canonical_spec(self) -> Tuple[str, str]:
        canonical_version = canonicalize_version(
            self._spec[1],
            strip_trailing_zero=(self._spec[0] != "~="),
        )
        return self._spec[0], canonical_version

    def __hash__(self) -> int:
        return hash(self._canonical_spec)

    def __eq__(self, other: object) -> bool:
        """Whether or not the two Specifier-like objects are equal.

        :param other: The other object to check against.

        The value of :attr:`prereleases` is ignored.

        >>> Specifier("==1.2.3") == Specifier("== 1.2.3.0")
        True
        >>> (Specifier("==1.2.3", prereleases=False) ==
        ...  Specifier("==1.2.3", prereleases=True))
        True
        >>> Specifier("==1.2.3") == "==1.2.3"
        True
        >>> Specifier("==1.2.3") == Specifier("==1.2.4")
        False
        >>> Specifier("==1.2.3") == Specifier("~=1.2.3")
        False
        """
        if isinstance(other, str):
            try:
                other = self.__class__(str(other))
            except InvalidSpecifier:
                return NotImplemented
        elif not isinstance(other, self.__class__):
            return NotImplemented

        return self._canonical_spec == other._canonical_spec

    def _get_operator(self, op: str) -> CallableOperator:
        operator_callable: CallableOperator = getattr(
            self, f"_compare_{self._operators[op]}"
        )
        return operator_callable

    def _compare_compatible(self, prospective: Version, spec: str) -> bool:

        # Compatible releases have an equivalent combination of >= and ==. That
        # is that ~=2.2 is equivalent to >=2.2,==2.*. This allows us to
        # implement this in terms of the other specifiers instead of
        # implementing it ourselves. The only thing we need to do is construct
        # the other specifiers.

        # We want everything but the last item in the version, but we want to
        # ignore suffix segments.
        prefix = ".".join(
            list(itertools.takewhile(_is_not_suffix, _version_split(spec)))[:-1]
        )

        # Add the prefix notation to the end of our string
        prefix += ".*"

        return self._get_operator(">=")(prospective, spec) and self._get_operator("==")(
            prospective, prefix
        )

    def _compare_equal(self, prospective: Version, spec: str) -> bool:

        # We need special logic to handle prefix matching
        if spec.endswith(".*"):
            # In the case of prefix matching we want to ignore local segment.
            normalized_prospective = canonicalize_version(prospective.public)
            # Get the normalized version string ignoring the trailing .*
            normalized_spec = canonicalize_version(spec[:-2], strip_trailing_zero=False)
            # Split the spec out by dots, and pretend that there is an implicit
            # dot in between a release segment and a pre-release segment.
            split_spec = _version_split(normalized_spec)

            # Split the prospective version out by dots, and pretend that there
            # is an implicit dot in between a release segment and a pre-release
            # segment.
            split_prospective = _version_split(normalized_prospective)

            # 0-pad the prospective version before shortening it to get the correct
            # shortened version.
            padded_prospective, _ = _pad_version(split_prospective, split_spec)

            # Shorten the prospective version to be the same length as the spec
            # so that we can determine if the specifier is a prefix of the
            # prospective version or not.
            shortened_prospective = padded_prospective[: len(split_spec)]

            return shortened_prospective == split_spec
        else:
            # Convert our spec string into a Version
            spec_version = Version(spec)

            # If the specifier does not have a local segment, then we want to
            # act as if the prospective version also does not have a local
            # segment.
            if not spec_version.local:
                prospective = Version(prospective.public)

            return prospective == spec_version

    def _compare_not_equal(self, prospective: Version, spec: str) -> bool:
        return not self._compare_equal(prospective, spec)

    def _compare_less_than_equal(self, prospective: Version, spec: str) -> bool:

        # NB: Local version identifiers are NOT permitted in the version
        # specifier, so local version labels can be universally removed from
        # the prospective version.
        return Version(prospective.public) <= Version(spec)

    def _compare_greater_than_equal(self, prospective: Version, spec: str) -> bool:

        # NB: Local version identifiers are NOT permitted in the version
        # specifier, so local version labels can be universally removed from
        # the prospective version.
        return Version(prospective.public) >= Version(spec)

    def _compare_less_than(self, prospective: Version, spec_str: str) -> bool:

        # Convert our spec to a Version instance, since we'll want to work with
        # it as a version.
        spec = Version(spec_str)

        # Check to see if the prospective version is less than the spec
        # version. If it's not we can short circuit and just return False now
        # instead of doing extra unneeded work.
        if not prospective < spec:
            return False

        # This special case is here so that, unless the specifier itself
        # includes is a pre-release version, that we do not accept pre-release
        # versions for the version mentioned in the specifier (e.g. <3.1 should
        # not match 3.1.dev0, but should match 3.0.dev0).
        if not spec.is_prerelease and prospective.is_prerelease:
            if Version(prospective.base_version) == Version(spec.base_version):
                return False

        # If we've gotten to here, it means that prospective version is both
        # less than the spec version *and* it's not a pre-release of the same
        # version in the spec.
        return True

    def _compare_greater_than(self, prospective: Version, spec_str: str) -> bool:

        # Convert our spec to a Version instance, since we'll want to work with
        # it as a version.
        spec = Version(spec_str)

        # Check to see if the prospective version is greater than the spec
        # version. If it's not we can short circuit and just return False now
        # instead of doing extra unneeded work.
        if not prospective > spec:
            return False

        # This special case is here so that, unless the specifier itself
        # includes is a post-release version, that we do not accept
        # post-release versions for the version mentioned in the specifier
        # (e.g. >3.1 should not match 3.0.post0, but should match 3.2.post0).
        if not spec.is_postrelease and prospective.is_postrelease:
            if Version(prospective.base_version) == Version(spec.base_version):
                return False

        # Ensure that we do not allow a local version of the version mentioned
        # in the specifier, which is technically greater than, to match.
        if prospective.local is not None:
            if Version(prospective.base_version) == Version(spec.base_version):
                return False

        # If we've gotten to here, it means that prospective version is both
        # greater than the spec version *and* it's not a pre-release of the
        # same version in the spec.
        return True

    def _compare_arbitrary(self, prospective: Version, spec: str) -> bool:
        return str(prospective).lower() == str(spec).lower()

    def __contains__(self, item: Union[str, Version]) -> bool:
        """Return whether or not the item is contained in this specifier.

        :param item: The item to check for.

        This is used for the ``in`` operator and behaves the same as
        :meth:`contains` with no ``prereleases`` argument passed.

        >>> "1.2.3" in Specifier(">=1.2.3")
        True
        >>> Version("1.2.3") in Specifier(">=1.2.3")
        True
        >>> "1.0.0" in Specifier(">=1.2.3")
        False
        >>> "1.3.0a1" in Specifier(">=1.2.3")
        False
        >>> "1.3.0a1" in Specifier(">=1.2.3", prereleases=True)
        True
        """
        return self.contains(item)

    def contains(
        self, item: UnparsedVersion, prereleases: Optional[bool] = None
    ) -> bool:
        """Return whether or not the item is contained in this specifier.

        :param item:
            The item to check for, which can be a version string or a
            :class:`Version` instance.
        :param prereleases:
            Whether or not to match prereleases with this Specifier. If set to
            ``None`` (the default), it uses :attr:`prereleases` to determine
            whether or not prereleases are allowed.

        >>> Specifier(">=1.2.3").contains("1.2.3")
        True
        >>> Specifier(">=1.2.3").contains(Version("1.2.3"))
        True
        >>> Specifier(">=1.2.3").contains("1.0.0")
        False
        >>> Specifier(">=1.2.3").contains("1.3.0a1")
        False
        >>> Specifier(">=1.2.3", prereleases=True).contains("1.3.0a1")
        True
        >>> Specifier(">=1.2.3").contains("1.3.0a1", prereleases=True)
        True
        """

        # Determine if prereleases are to be allowed or not.
        if prereleases is None:
            prereleases = self.prereleases

        # Normalize item to a Version, this allows us to have a shortcut for
        # "2.0" in Specifier(">=2")
        normalized_item = _coerce_version(item)

        # Determine if we should be supporting prereleases in this specifier
        # or not, if we do not support prereleases than we can short circuit
        # logic if this version is a prereleases.
        if normalized_item.is_prerelease and not prereleases:
            return False

        # Actually do the comparison to determine if this item is contained
        # within this Specifier or not.
        operator_callable: CallableOperator = self._get_operator(self.operator)
        return operator_callable(normalized_item, self.version)

    def filter(
        self, iterable: Iterable[UnparsedVersionVar], prereleases: Optional[bool] = None
    ) -> Iterator[UnparsedVersionVar]:
        """Filter items in the given iterable, that match the specifier.

        :param iterable:
            An iterable that can contain version strings and :class:`Version` instances.
            The items in the iterable will be filtered according to the specifier.
        :param prereleases:
            Whether or not to allow prereleases in the returned iterator. If set to
            ``None`` (the default), it will be intelligently decide whether to allow
            prereleases or not (based on the :attr:`prereleases` attribute, and
            whether the only versions matching are prereleases).

        This method is smarter than just ``filter(Specifier().contains, [...])``
        because it implements the rule from :pep:`440` that a prerelease item
        SHOULD be accepted if no other versions match the given specifier.

        >>> list(Specifier(">=1.2.3").filter(["1.2", "1.3", "1.5a1"]))
        ['1.3']
        >>> list(Specifier(">=1.2.3").filter(["1.2", "1.2.3", "1.3", Version("1.4")]))
        ['1.2.3', '1.3', <Version('1.4')>]
        >>> list(Specifier(">=1.2.3").filter(["1.2", "1.5a1"]))
        ['1.5a1']
        >>> list(Specifier(">=1.2.3").filter(["1.3", "1.5a1"], prereleases=True))
        ['1.3', '1.5a1']
        >>> list(Specifier(">=1.2.3", prereleases=True).filter(["1.3", "1.5a1"]))
        ['1.3', '1.5a1']
        """

        yielded = False
        found_prereleases = []

        kw = {"prereleases": prereleases if prereleases is not None else True}

        # Attempt to iterate over all the values in the iterable and if any of
        # them match, yield them.
        for version in iterable:
            parsed_version = _coerce_version(version)

            if self.contains(parsed_version, **kw):
                # If our version is a prerelease, and we were not set to allow
                # prereleases, then we'll store it for later in case nothing
                # else matches this specifier.
                if parsed_version.is_prerelease and not (
                    prereleases or self.prereleases
                ):
                    found_prereleases.append(version)
                # Either this is not a prerelease, or we should have been
                # accepting prereleases from the beginning.
                else:
                    yielded = True
                    yield version

        # Now that we've iterated over everything, determine if we've yielded
        # any values, and if we have not and we have any prereleases stored up
        # then we will go ahead and yield the prereleases.
        if not yielded and found_prereleases:
            for version in found_prereleases:
                yield version


_prefix_regex = re.compile(r"^([0-9]+)((?:a|b|c|rc)[0-9]+)$")


def _version_split(version: str) -> List[str]:
    result: List[str] = []
    for item in version.split("."):
        match = _prefix_regex.search(item)
        if match:
            result.extend(match.groups())
        else:
            result.append(item)
    return result


def _is_not_suffix(segment: str) -> bool:
    return not any(
        segment.startswith(prefix) for prefix in ("dev", "a", "b", "rc", "post")
    )


def _pad_version(left: List[str], right: List[str]) -> Tuple[List[str], List[str]]:
    left_split, right_split = [], []

    # Get the release segment of our versions
    left_split.append(list(itertools.takewhile(lambda x: x.isdigit(), left)))
    right_split.append(list(itertools.takewhile(lambda x: x.isdigit(), right)))

    # Get the rest of our versions
    left_split.append(left[len(left_split[0]) :])
    right_split.append(right[len(right_split[0]) :])

    # Insert our padding
    left_split.insert(1, ["0"] * max(0, len(right_split[0]) - len(left_split[0])))
    right_split.insert(1, ["0"] * max(0, len(left_split[0]) - len(right_split[0])))

    return (list(itertools.chain(*left_split)), list(itertools.chain(*right_split)))


class SpecifierSet(BaseSpecifier):
    """This class abstracts handling of a set of version specifiers.

    It can be passed a single specifier (``>=3.0``), a comma-separated list of
    specifiers (``>=3.0,!=3.1``), or no specifier at all.
    """

    def __init__(
        self, specifiers: str = "", prereleases: Optional[bool] = None
    ) -> None:
        """Initialize a SpecifierSet instance.

        :param specifiers:
            The string representation of a specifier or a comma-separated list of
            specifiers which will be parsed and normalized before use.
        :param prereleases:
            This tells the SpecifierSet if it should accept prerelease versions if
            applicable or not. The default of ``None`` will autodetect it from the
            given specifiers.

        :raises InvalidSpecifier:
            If the given ``specifiers`` are not parseable than this exception will be
            raised.
        """

        # Split on `,` to break each individual specifier into it's own item, and
        # strip each item to remove leading/trailing whitespace.
        split_specifiers = [s.strip() for s in specifiers.split(",") if s.strip()]

        # Parsed each individual specifier, attempting first to make it a
        # Specifier.
        parsed: Set[Specifier] = set()
        for specifier in split_specifiers:
            parsed.add(Specifier(specifier))

        # Turn our parsed specifiers into a frozen set and save them for later.
        self._specs = frozenset(parsed)

        # Store our prereleases value so we can use it later to determine if
        # we accept prereleases or not.
        self._prereleases = prereleases

    @property
    def prereleases(self) -> Optional[bool]:
        # If we have been given an explicit prerelease modifier, then we'll
        # pass that through here.
        if self._prereleases is not None:
            return self._prereleases

        # If we don't have any specifiers, and we don't have a forced value,
        # then we'll just return None since we don't know if this should have
        # pre-releases or not.
        if not self._specs:
            return None

        # Otherwise we'll see if any of the given specifiers accept
        # prereleases, if any of them do we'll return True, otherwise False.
        return any(s.prereleases for s in self._specs)

    @prereleases.setter
    def prereleases(self, value: bool) -> None:
        self._prereleases = value

    def __repr__(self) -> str:
        """A representation of the specifier set that shows all internal state.

        Note that the ordering of the individual specifiers within the set may not
        match the input string.

        >>> SpecifierSet('>=1.0.0,!=2.0.0')
        <SpecifierSet('!=2.0.0,>=1.0.0')>
        >>> SpecifierSet('>=1.0.0,!=2.0.0', prereleases=False)
        <SpecifierSet('!=2.0.0,>=1.0.0', prereleases=False)>
        >>> SpecifierSet('>=1.0.0,!=2.0.0', prereleases=True)
        <SpecifierSet('!=2.0.0,>=1.0.0', prereleases=True)>
        """
        pre = (
            f", prereleases={self.prereleases!r}"
            if self._prereleases is not None
            else ""
        )

        return f"<SpecifierSet({str(self)!r}{pre})>"

    def __str__(self) -> str:
        """A string representation of the specifier set that can be round-tripped.

        Note that the ordering of the individual specifiers within the set may not
        match the input string.

        >>> str(SpecifierSet(">=1.0.0,!=1.0.1"))
        '!=1.0.1,>=1.0.0'
        >>> str(SpecifierSet(">=1.0.0,!=1.0.1", prereleases=False))
        '!=1.0.1,>=1.0.0'
        """
        return ",".join(sorted(str(s) for s in self._specs))

    def __hash__(self) -> int:
        return hash(self._specs)

    def __and__(self, other: Union["SpecifierSet", str]) -> "SpecifierSet":
        """Return a SpecifierSet which is a combination of the two sets.

        :param other: The other object to combine with.

        >>> SpecifierSet(">=1.0.0,!=1.0.1") & '<=2.0.0,!=2.0.1'
        <SpecifierSet('!=1.0.1,!=2.0.1,<=2.0.0,>=1.0.0')>
        >>> SpecifierSet(">=1.0.0,!=1.0.1") & SpecifierSet('<=2.0.0,!=2.0.1')
        <SpecifierSet('!=1.0.1,!=2.0.1,<=2.0.0,>=1.0.0')>
        """
        if isinstance(other, str):
            other = SpecifierSet(other)
        elif not isinstance(other, SpecifierSet):
            return NotImplemented

        specifier = SpecifierSet()
        specifier._specs = frozenset(self._specs | other._specs)

        if self._prereleases is None and other._prereleases is not None:
            specifier._prereleases = other._prereleases
        elif self._prereleases is not None and other._prereleases is None:
            specifier._prereleases = self._prereleases
        elif self._prereleases == other._prereleases:
            specifier._prereleases = self._prereleases
        else:
            raise ValueError(
                "Cannot combine SpecifierSets with True and False prerelease "
                "overrides."
            )

        return specifier

    def __eq__(self, other: object) -> bool:
        """Whether or not the two SpecifierSet-like objects are equal.

        :param other: The other object to check against.

        The value of :attr:`prereleases` is ignored.

        >>> SpecifierSet(">=1.0.0,!=1.0.1") == SpecifierSet(">=1.0.0,!=1.0.1")
        True
        >>> (SpecifierSet(">=1.0.0,!=1.0.1", prereleases=False) ==
        ...  SpecifierSet(">=1.0.0,!=1.0.1", prereleases=True))
        True
        >>> SpecifierSet(">=1.0.0,!=1.0.1") == ">=1.0.0,!=1.0.1"
        True
        >>> SpecifierSet(">=1.0.0,!=1.0.1") == SpecifierSet(">=1.0.0")
        False
        >>> SpecifierSet(">=1.0.0,!=1.0.1") == SpecifierSet(">=1.0.0,!=1.0.2")
        False
        """
        if isinstance(other, (str, Specifier)):
            other = SpecifierSet(str(other))
        elif not isinstance(other, SpecifierSet):
            return NotImplemented

        return self._specs == other._specs

    def __len__(self) -> int:
        """Returns the number of specifiers in this specifier set."""
        return len(self._specs)

    def __iter__(self) -> Iterator[Specifier]:
        """
        Returns an iterator over all the underlying :class:`Specifier` instances
        in this specifier set.

        >>> sorted(SpecifierSet(">=1.0.0,!=1.0.1"), key=str)
        [<Specifier('!=1.0.1')>, <Specifier('>=1.0.0')>]
        """
        return iter(self._specs)

    def __contains__(self, item: UnparsedVersion) -> bool:
        """Return whether or not the item is contained in this specifier.

        :param item: The item to check for.

        This is used for the ``in`` operator and behaves the same as
        :meth:`contains` with no ``prereleases`` argument passed.

        >>> "1.2.3" in SpecifierSet(">=1.0.0,!=1.0.1")
        True
        >>> Version("1.2.3") in SpecifierSet(">=1.0.0,!=1.0.1")
        True
        >>> "1.0.1" in SpecifierSet(">=1.0.0,!=1.0.1")
        False
        >>> "1.3.0a1" in SpecifierSet(">=1.0.0,!=1.0.1")
        False
        >>> "1.3.0a1" in SpecifierSet(">=1.0.0,!=1.0.1", prereleases=True)
        True
        """
        return self.contains(item)

    def contains(
        self,
        item: UnparsedVersion,
        prereleases: Optional[bool] = None,
        installed: Optional[bool] = None,
    ) -> bool:
        """Return whether or not the item is contained in this SpecifierSet.

        :param item:
            The item to check for, which can be a version string or a
            :class:`Version` instance.
        :param prereleases:
            Whether or not to match prereleases with this SpecifierSet. If set to
            ``None`` (the default), it uses :attr:`prereleases` to determine
            whether or not prereleases are allowed.

        >>> SpecifierSet(">=1.0.0,!=1.0.1").contains("1.2.3")
        True
        >>> SpecifierSet(">=1.0.0,!=1.0.1").contains(Version("1.2.3"))
        True
        >>> SpecifierSet(">=1.0.0,!=1.0.1").contains("1.0.1")
        False
        >>> SpecifierSet(">=1.0.0,!=1.0.1").contains("1.3.0a1")
        False
        >>> SpecifierSet(">=1.0.0,!=1.0.1", prereleases=True).contains("1.3.0a1")
        True
        >>> SpecifierSet(">=1.0.0,!=1.0.1").contains("1.3.0a1", prereleases=True)
        True
        """
        # Ensure that our item is a Version instance.
        if not isinstance(item, Version):
            item = Version(item)

        # Determine if we're forcing a prerelease or not, if we're not forcing
        # one for this particular filter call, then we'll use whatever the
        # SpecifierSet thinks for whether or not we should support prereleases.
        if prereleases is None:
            prereleases = self.prereleases

        # We can determine if we're going to allow pre-releases by looking to
        # see if any of the underlying items supports them. If none of them do
        # and this item is a pre-release then we do not allow it and we can
        # short circuit that here.
        # Note: This means that 1.0.dev1 would not be contained in something
        #       like >=1.0.devabc however it would be in >=1.0.debabc,>0.0.dev0
        if not prereleases and item.is_prerelease:
            return False

        if installed and item.is_prerelease:
            item = Version(item.base_version)

        # We simply dispatch to the underlying specs here to make sure that the
        # given version is contained within all of them.
        # Note: This use of all() here means that an empty set of specifiers
        #       will always return True, this is an explicit design decision.
        return all(s.contains(item, prereleases=prereleases) for s in self._specs)

    def filter(
        self, iterable: Iterable[UnparsedVersionVar], prereleases: Optional[bool] = None
    ) -> Iterator[UnparsedVersionVar]:
        """Filter items in the given iterable, that match the specifiers in this set.

        :param iterable:
            An iterable that can contain version strings and :class:`Version` instances.
            The items in the iterable will be filtered according to the specifier.
        :param prereleases:
            Whether or not to allow prereleases in the returned iterator. If set to
            ``None`` (the default), it will be intelligently decide whether to allow
            prereleases or not (based on the :attr:`prereleases` attribute, and
            whether the only versions matching are prereleases).

        This method is smarter than just ``filter(SpecifierSet(...).contains, [...])``
        because it implements the rule from :pep:`440` that a prerelease item
        SHOULD be accepted if no other versions match the given specifier.

        >>> list(SpecifierSet(">=1.2.3").filter(["1.2", "1.3", "1.5a1"]))
        ['1.3']
        >>> list(SpecifierSet(">=1.2.3").filter(["1.2", "1.3", Version("1.4")]))
        ['1.3', <Version('1.4')>]
        >>> list(SpecifierSet(">=1.2.3").filter(["1.2", "1.5a1"]))
        []
        >>> list(SpecifierSet(">=1.2.3").filter(["1.3", "1.5a1"], prereleases=True))
        ['1.3', '1.5a1']
        >>> list(SpecifierSet(">=1.2.3", prereleases=True).filter(["1.3", "1.5a1"]))
        ['1.3', '1.5a1']

        An "empty" SpecifierSet will filter items based on the presence of prerelease
        versions in the set.

        >>> list(SpecifierSet("").filter(["1.3", "1.5a1"]))
        ['1.3']
        >>> list(SpecifierSet("").filter(["1.5a1"]))
        ['1.5a1']
        >>> list(SpecifierSet("", prereleases=True).filter(["1.3", "1.5a1"]))
        ['1.3', '1.5a1']
        >>> list(SpecifierSet("").filter(["1.3", "1.5a1"], prereleases=True))
        ['1.3', '1.5a1']
        """
        # Determine if we're forcing a prerelease or not, if we're not forcing
        # one for this particular filter call, then we'll use whatever the
        # SpecifierSet thinks for whether or not we should support prereleases.
        if prereleases is None:
            prereleases = self.prereleases

        # If we have any specifiers, then we want to wrap our iterable in the
        # filter method for each one, this will act as a logical AND amongst
        # each specifier.
        if self._specs:
            for spec in self._specs:
                iterable = spec.filter(iterable, prereleases=bool(prereleases))
            return iter(iterable)
        # If we do not have any specifiers, then we need to have a rough filter
        # which will filter out any pre-releases, unless there are no final
        # releases.
        else:
            filtered: List[UnparsedVersionVar] = []
            found_prereleases: List[UnparsedVersionVar] = []

            for item in iterable:
                parsed_version = _coerce_version(item)

                # Store any item which is a pre-release for later unless we've
                # already found a final version or we are accepting prereleases
                if parsed_version.is_prerelease and not prereleases:
                    if not filtered:
                        found_prereleases.append(item)
                else:
                    filtered.append(item)

            # If we've found no items except for pre-releases, then we'll go
            # ahead and use the pre-releases
            if not filtered and found_prereleases and prereleases is None:
                return iter(found_prereleases)

            return iter(filtered)