SpecifierSet class final

SpecifierSet

python docstring

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.

python source

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)