from __future__ import annotations

import functools
import logging
import os
import re
import tempfile
import time
import urllib.parse

from collections import defaultdict
from contextlib import contextmanager
from pathlib import Path
from typing import TYPE_CHECKING
from typing import Any
from typing import Iterable
from typing import Iterator
from typing import cast

from cleo.ui.progress_indicator import ProgressIndicator
from poetry.core.packages.directory_dependency import DirectoryDependency
from poetry.core.packages.file_dependency import FileDependency
from poetry.core.packages.url_dependency import URLDependency
from poetry.core.packages.utils.utils import get_python_constraint_from_marker
from poetry.core.packages.vcs_dependency import VCSDependency
from poetry.core.semver.empty_constraint import EmptyConstraint
from poetry.core.semver.version import Version
from poetry.core.version.markers import AnyMarker
from poetry.core.version.markers import MarkerUnion

from poetry.inspection.info import PackageInfo
from poetry.inspection.info import PackageInfoError
from poetry.mixology.incompatibility import Incompatibility
from poetry.mixology.incompatibility_cause import DependencyCause
from poetry.mixology.incompatibility_cause import PythonCause
from poetry.mixology.term import Term
from poetry.packages import DependencyPackage
from poetry.packages.package_collection import PackageCollection
from poetry.puzzle.exceptions import OverrideNeeded
from poetry.utils.helpers import download_file
from poetry.vcs.git import Git


if TYPE_CHECKING:
    from poetry.core.packages.dependency import Dependency
    from poetry.core.packages.package import Package
    from poetry.core.semver.version_constraint import VersionConstraint
    from poetry.core.version.markers import BaseMarker

    from poetry.repositories import Pool
    from poetry.utils.env import Env


logger = logging.getLogger(__name__)


class Indicator(ProgressIndicator):  # type: ignore[misc]
    def _formatter_elapsed(self) -> str:
        elapsed = time.time() - self._start_time

        return f"{elapsed:.1f}s"


@functools.lru_cache(maxsize=None)
def _get_package_from_git(
    url: str,
    branch: str | None = None,
    tag: str | None = None,
    rev: str | None = None,
    source_root: Path | None = None,
) -> Package:
    source = Git.clone(
        url=url,
        source_root=source_root,
        branch=branch,
        tag=tag,
        revision=rev,
        clean=False,
    )
    revision = Git.get_revision(source)

    package = Provider.get_package_from_directory(Path(source.path))
    package._source_type = "git"
    package._source_url = url
    package._source_reference = rev or tag or branch or "HEAD"
    package._source_resolved_reference = revision

    return package


class Provider:

    UNSAFE_PACKAGES: set[str] = set()

    def __init__(
        self,
        package: Package,
        pool: Pool,
        io: Any,
        env: Env | None = None,
    ) -> None:
        self._package = package
        self._pool = pool
        self._io = io
        self._env = env
        self._python_constraint = package.python_constraint
        self._is_debugging: bool = self._io.is_debug() or self._io.is_very_verbose()
        self._in_progress = False
        self._overrides: dict[DependencyPackage, dict[str, Dependency]] = {}
        self._deferred_cache: dict[Dependency, Package] = {}
        self._load_deferred = True
        self._source_root: Path | None = None

    @property
    def pool(self) -> Pool:
        return self._pool

    def is_debugging(self) -> bool:
        return self._is_debugging

    def set_overrides(
        self, overrides: dict[DependencyPackage, dict[str, Dependency]]
    ) -> None:
        self._overrides = overrides

    def load_deferred(self, load_deferred: bool) -> None:
        self._load_deferred = load_deferred

    @contextmanager
    def use_source_root(self, source_root: Path) -> Iterator[Provider]:
        original_source_root = self._source_root
        self._source_root = source_root

        yield self

        self._source_root = original_source_root

    @contextmanager
    def use_environment(self, env: Env) -> Iterator[Provider]:
        original_env = self._env
        original_python_constraint = self._python_constraint

        self._env = env
        self._python_constraint = Version.parse(env.marker_env["python_full_version"])

        yield self

        self._env = original_env
        self._python_constraint = original_python_constraint

    @staticmethod
    def validate_package_for_dependency(
        dependency: Dependency, package: Package
    ) -> None:
        if dependency.name != package.name:
            # For now, the dependency's name must match the actual package's name
            raise RuntimeError(
                f"The dependency name for {dependency.name} does not match the actual"
                f" package's name: {package.name}"
            )

    def search_for(
        self,
        dependency: (
            Dependency
            | VCSDependency
            | FileDependency
            | DirectoryDependency
            | URLDependency
        ),
    ) -> list[DependencyPackage]:
        """
        Search for the specifications that match the given dependency.

        The specifications in the returned list will be considered in reverse
        order, so the latest version ought to be last.
        """
        if dependency.is_root:
            return PackageCollection(dependency, [self._package])

        if dependency.is_vcs():
            dependency = cast(VCSDependency, dependency)
            packages = self.search_for_vcs(dependency)
        elif dependency.is_file():
            dependency = cast(FileDependency, dependency)
            packages = self.search_for_file(dependency)
        elif dependency.is_directory():
            dependency = cast(DirectoryDependency, dependency)
            packages = self.search_for_directory(dependency)
        elif dependency.is_url():
            dependency = cast(URLDependency, dependency)
            packages = self.search_for_url(dependency)
        else:
            packages = self._pool.find_packages(dependency)

            packages.sort(
                key=lambda p: (
                    not p.is_prerelease() and not dependency.allows_prereleases(),
                    p.version,
                ),
                reverse=True,
            )

        return PackageCollection(dependency, packages)

    def search_for_vcs(self, dependency: VCSDependency) -> list[Package]:
        """
        Search for the specifications that match the given VCS dependency.

        Basically, we clone the repository in a temporary directory
        and get the information we need by checking out the specified reference.
        """
        if dependency in self._deferred_cache:
            return [self._deferred_cache[dependency]]

        package = self.get_package_from_vcs(
            dependency.vcs,
            dependency.source,
            branch=dependency.branch,
            tag=dependency.tag,
            rev=dependency.rev,
            source_root=self._source_root
            or (self._env.path.joinpath("src") if self._env else None),
        )

        self.validate_package_for_dependency(dependency=dependency, package=package)

        package.develop = dependency.develop

        dependency._constraint = package.version
        dependency._pretty_constraint = package.version.text

        dependency._source_reference = package.source_reference
        dependency._source_resolved_reference = package.source_resolved_reference
        dependency._source_subdirectory = package.source_subdirectory

        self._deferred_cache[dependency] = package

        return [package]

    @staticmethod
    def get_package_from_vcs(
        vcs: str,
        url: str,
        branch: str | None = None,
        tag: str | None = None,
        rev: str | None = None,
        source_root: Path | None = None,
    ) -> Package:
        if vcs != "git":
            raise ValueError(f"Unsupported VCS dependency {vcs}")

        return _get_package_from_git(
            url=url, branch=branch, tag=tag, rev=rev, source_root=source_root
        )

    def search_for_file(self, dependency: FileDependency) -> list[Package]:
        if dependency in self._deferred_cache:
            _package = self._deferred_cache[dependency]

            package = _package.clone()
        else:
            package = self.get_package_from_file(dependency.full_path)

            dependency._constraint = package.version
            dependency._pretty_constraint = package.version.text

            self._deferred_cache[dependency] = package

        self.validate_package_for_dependency(dependency=dependency, package=package)

        if dependency.base is not None:
            package.root_dir = dependency.base

        package.files = [
            {"file": dependency.path.name, "hash": "sha256:" + dependency.hash()}
        ]

        return [package]

    @classmethod
    def get_package_from_file(cls, file_path: Path) -> Package:
        try:
            package = PackageInfo.from_path(path=file_path).to_package(
                root_dir=file_path
            )
        except PackageInfoError:
            raise RuntimeError(
                f"Unable to determine package info from path: {file_path}"
            )

        return package

    def search_for_directory(self, dependency: DirectoryDependency) -> list[Package]:
        if dependency in self._deferred_cache:
            _package = self._deferred_cache[dependency]

            package = _package.clone()
        else:
            package = self.get_package_from_directory(dependency.full_path)

            dependency._constraint = package.version
            dependency._pretty_constraint = package.version.text

            self._deferred_cache[dependency] = package

        self.validate_package_for_dependency(dependency=dependency, package=package)

        package.develop = dependency.develop

        if dependency.base is not None:
            package.root_dir = dependency.base

        return [package]

    @classmethod
    def get_package_from_directory(cls, directory: Path) -> Package:
        return PackageInfo.from_directory(path=directory).to_package(root_dir=directory)

    def search_for_url(self, dependency: URLDependency) -> list[Package]:
        if dependency in self._deferred_cache:
            return [self._deferred_cache[dependency]]

        package = self.get_package_from_url(dependency.url)

        self.validate_package_for_dependency(dependency=dependency, package=package)

        for extra in dependency.extras:
            if extra in package.extras:
                for dep in package.extras[extra]:
                    dep.activate()

                for extra_dep in package.extras[extra]:
                    package.add_dependency(extra_dep)

        dependency._constraint = package.version
        dependency._pretty_constraint = package.version.text

        self._deferred_cache[dependency] = package

        return [package]

    @classmethod
    def get_package_from_url(cls, url: str) -> Package:
        file_name = os.path.basename(urllib.parse.urlparse(url).path)
        with tempfile.TemporaryDirectory() as temp_dir:
            dest = Path(temp_dir) / file_name
            download_file(url, str(dest))
            package = cls.get_package_from_file(dest)

        package._source_type = "url"
        package._source_url = url

        return package

    def _get_dependencies_with_overrides(
        self, dependencies: list[Dependency], package: DependencyPackage
    ) -> list[Dependency]:
        overrides = self._overrides.get(package, {})
        _dependencies = []
        overridden = []
        for dep in dependencies:
            if dep.name in overrides:
                if dep.name in overridden:
                    continue

                # empty constraint is used in overrides to mark that the package has
                # already been handled and is not required for the attached markers
                if not overrides[dep.name].constraint.is_empty():
                    _dependencies.append(overrides[dep.name])
                overridden.append(dep.name)

                continue

            _dependencies.append(dep)
        return _dependencies

    def incompatibilities_for(
        self, package: DependencyPackage
    ) -> list[Incompatibility]:
        """
        Returns incompatibilities that encapsulate a given package's dependencies,
        or that it can't be safely selected.

        If multiple subsequent versions of this package have the same
        dependencies, this will return incompatibilities that reflect that. It
        won't return incompatibilities that have already been returned by a
        previous call to _incompatibilities_for().
        """
        if package.is_root():
            dependencies = package.all_requires
        else:
            dependencies = package.requires

            if not package.python_constraint.allows_all(self._python_constraint):
                transitive_python_constraint = get_python_constraint_from_marker(
                    package.dependency.transitive_marker
                )
                intersection = package.python_constraint.intersect(
                    transitive_python_constraint
                )
                difference = transitive_python_constraint.difference(intersection)

                # The difference is only relevant if it intersects
                # the root package python constraint
                difference = difference.intersect(self._python_constraint)
                if (
                    transitive_python_constraint.is_any()
                    or self._python_constraint.intersect(
                        package.dependency.python_constraint
                    ).is_empty()
                    or intersection.is_empty()
                    or not difference.is_empty()
                ):
                    return [
                        Incompatibility(
                            [Term(package.to_dependency(), True)],
                            PythonCause(
                                package.python_versions, str(self._python_constraint)
                            ),
                        )
                    ]

        _dependencies = [
            dep
            for dep in dependencies
            if dep.name not in self.UNSAFE_PACKAGES
            and self._python_constraint.allows_any(dep.python_constraint)
            and (not self._env or dep.marker.validate(self._env.marker_env))
        ]
        dependencies = self._get_dependencies_with_overrides(_dependencies, package)

        return [
            Incompatibility(
                [Term(package.to_dependency(), True), Term(dep, False)],
                DependencyCause(),
            )
            for dep in dependencies
        ]

    def complete_package(self, package: DependencyPackage) -> DependencyPackage:
        if package.is_root():
            package = package.clone()
            requires = package.all_requires
        elif not package.is_root() and package.source_type not in {
            "directory",
            "file",
            "url",
            "git",
        }:
            package = DependencyPackage(
                package.dependency,
                self._pool.package(
                    package.name,
                    package.version.text,
                    extras=list(package.dependency.extras),
                    repository=package.dependency.source_name,
                ),
            )
            requires = package.requires
        else:
            requires = package.requires

        if self._load_deferred:
            # Retrieving constraints for deferred dependencies
            for r in requires:
                if r.is_directory():
                    self.search_for_directory(r)
                elif r.is_file():
                    self.search_for_file(r)
                elif r.is_vcs():
                    self.search_for_vcs(r)
                elif r.is_url():
                    self.search_for_url(r)

        optional_dependencies = []
        _dependencies = []

        # If some extras/features were required, we need to
        # add a special dependency representing the base package
        # to the current package
        if package.dependency.extras:
            for extra in package.dependency.extras:
                if extra not in package.extras:
                    continue

                optional_dependencies += [d.name for d in package.extras[extra]]

            package = package.with_features(list(package.dependency.extras))
            _dependencies.append(package.without_features().to_dependency())

        for dep in requires:
            if not self._python_constraint.allows_any(dep.python_constraint):
                continue

            if dep.name in self.UNSAFE_PACKAGES:
                continue

            if self._env and not dep.marker.validate(self._env.marker_env):
                continue

            if not package.is_root() and (
                (dep.is_optional() and dep.name not in optional_dependencies)
                or (
                    dep.in_extras
                    and not set(dep.in_extras).intersection(package.dependency.extras)
                )
            ):
                continue

            _dependencies.append(dep)

        dependencies = self._get_dependencies_with_overrides(_dependencies, package)

        # Searching for duplicate dependencies
        #
        # If the duplicate dependencies have the same constraint,
        # the requirements will be merged.
        #
        # For instance:
        #   - enum34; python_version=="2.7"
        #   - enum34; python_version=="3.3"
        #
        # will become:
        #   - enum34; python_version=="2.7" or python_version=="3.3"
        #
        # If the duplicate dependencies have different constraints
        # we have to split the dependency graph.
        #
        # An example of this is:
        #   - pypiwin32 (220); sys_platform == "win32" and python_version >= "3.6"
        #   - pypiwin32 (219); sys_platform == "win32" and python_version < "3.6"
        duplicates: dict[str, list[Dependency]] = {}
        for dep in dependencies:
            if dep.complete_name not in duplicates:
                duplicates[dep.complete_name] = []

            duplicates[dep.complete_name].append(dep)

        dependencies = []
        for dep_name, deps in duplicates.items():
            if len(deps) == 1:
                dependencies.append(deps[0])
                continue

            self.debug(f"<debug>Duplicate dependencies for {dep_name}</debug>")

            deps = self._merge_dependencies_by_marker(deps)
            deps = self._merge_dependencies_by_constraint(deps)

            if len(deps) == 1:
                self.debug(f"<debug>Merging requirements for {deps[0]!s}</debug>")
                dependencies.append(deps[0])
                continue

            # We leave dependencies as-is if they have the same
            # python/platform constraints.
            # That way the resolver will pickup the conflict
            # and display a proper error.
            seen = set()
            for dep in deps:
                pep_508_dep = dep.to_pep_508(False)
                if ";" not in pep_508_dep:
                    _requirements = ""
                else:
                    _requirements = pep_508_dep.split(";")[1].strip()

                if _requirements not in seen:
                    seen.add(_requirements)

            if len(deps) != len(seen):
                for dep in deps:
                    dependencies.append(dep)

                continue

            # At this point, we raise an exception that will
            # tell the solver to make new resolutions with specific overrides.
            #
            # For instance, if the foo (1.2.3) package has the following dependencies:
            #   - bar (>=2.0) ; python_version >= "3.6"
            #   - bar (<2.0) ; python_version < "3.6"
            #
            # then the solver will need to make two new resolutions
            # with the following overrides:
            #   - {<Package foo (1.2.3): {"bar": <Dependency bar (>=2.0)>}
            #   - {<Package foo (1.2.3): {"bar": <Dependency bar (<2.0)>}

            def fmt_warning(d: Dependency) -> str:
                marker = d.marker if not d.marker.is_any() else "*"
                return (
                    f"<c1>{d.name}</c1> <fg=default>(<c2>{d.pretty_constraint}</c2>)</>"
                    f" with markers <b>{marker}</b>"
                )

            warnings = ", ".join(fmt_warning(d) for d in deps[:-1])
            warnings += f" and {fmt_warning(deps[-1])}"
            self.debug(
                f"<warning>Different requirements found for {warnings}.</warning>"
            )

            # We need to check if one of the duplicate dependencies
            # has no markers. If there is one, we need to change its
            # environment markers to the inverse of the union of the
            # other dependencies markers.
            # For instance, if we have the following dependencies:
            #   - ipython
            #   - ipython (1.2.4) ; implementation_name == "pypy"
            #
            # the marker for `ipython` will become `implementation_name != "pypy"`.
            #
            # Further, we have to merge the constraints of the requirements
            # without markers into the constraints of the requirements with markers.
            # for instance, if we have the following dependencies:
            #   - foo (>= 1.2)
            #   - foo (!= 1.2.1) ; python == 3.10
            #
            # the constraint for the second entry will become (!= 1.2.1, >= 1.2)
            any_markers_dependencies = [d for d in deps if d.marker.is_any()]
            other_markers_dependencies = [d for d in deps if not d.marker.is_any()]

            marker = other_markers_dependencies[0].marker
            for other_dep in other_markers_dependencies[1:]:
                marker = marker.union(other_dep.marker)
            inverted_marker = marker.invert()

            if any_markers_dependencies:
                for dep_any in any_markers_dependencies:
                    dep_any.marker = inverted_marker
                    for dep_other in other_markers_dependencies:
                        dep_other.set_constraint(
                            dep_other.constraint.intersect(dep_any.constraint)
                        )
            elif not inverted_marker.is_empty():
                # if there is no any marker dependency
                # and the inverted marker is not empty,
                # a dependency with the inverted union of all markers is required
                # in order to not miss other dependencies later, for instance:
                #   - foo (1.0) ; python == 3.7
                #   - foo (2.0) ; python == 3.8
                #   - bar (2.0) ; python == 3.8
                #   - bar (3.0) ; python == 3.9
                #
                # the last dependency would be missed without this,
                # because the intersection with both foo dependencies is empty
                inverted_marker_dep = deps[0].with_constraint(EmptyConstraint())
                inverted_marker_dep.marker = inverted_marker
                deps.append(inverted_marker_dep)

            overrides = []
            overrides_marker_intersection: BaseMarker = AnyMarker()
            for dep_overrides in self._overrides.values():
                for dep in dep_overrides.values():
                    overrides_marker_intersection = (
                        overrides_marker_intersection.intersect(dep.marker)
                    )
            for dep in deps:
                if not overrides_marker_intersection.intersect(dep.marker).is_empty():
                    current_overrides = self._overrides.copy()
                    package_overrides = current_overrides.get(package, {}).copy()
                    package_overrides.update({dep.name: dep})
                    current_overrides.update({package: package_overrides})
                    overrides.append(current_overrides)

            if overrides:
                raise OverrideNeeded(*overrides)

        # Modifying dependencies as needed
        clean_dependencies = []
        for dep in dependencies:
            if not package.dependency.transitive_marker.without_extras().is_any():
                marker_intersection = (
                    package.dependency.transitive_marker.without_extras().intersect(
                        dep.marker.without_extras()
                    )
                )
                if marker_intersection.is_empty():
                    # The dependency is not needed, since the markers specified
                    # for the current package selection are not compatible with
                    # the markers for the current dependency, so we skip it
                    continue

                dep.transitive_marker = marker_intersection

            if not package.dependency.python_constraint.is_any():
                python_constraint_intersection = dep.python_constraint.intersect(
                    package.dependency.python_constraint
                )
                if python_constraint_intersection.is_empty():
                    # This dependency is not needed under current python constraint.
                    continue
                dep.transitive_python_versions = str(python_constraint_intersection)

            clean_dependencies.append(dep)

        package = DependencyPackage(
            package.dependency, package.with_dependency_groups([], only=True)
        )

        for dep in clean_dependencies:
            package.add_dependency(dep)

        return package

    def debug(self, message: str, depth: int = 0) -> None:
        if not (self._io.is_very_verbose() or self._io.is_debug()):
            return

        if message.startswith("fact:"):
            if "depends on" in message:
                m = re.match(r"fact: (.+?) depends on (.+?) \((.+?)\)", message)
                if m is None:
                    raise ValueError(f"Unable to parse fact: {message}")
                m2 = re.match(r"(.+?) \((.+?)\)", m.group(1))
                if m2:
                    name = m2.group(1)
                    version = f" (<c2>{m2.group(2)}</c2>)"
                else:
                    name = m.group(1)
                    version = ""

                message = (
                    f"<fg=blue>fact</>: <c1>{name}</c1>{version} "
                    f"depends on <c1>{m.group(2)}</c1> (<c2>{m.group(3)}</c2>)"
                )
            elif " is " in message:
                message = re.sub(
                    "fact: (.+) is (.+)",
                    "<fg=blue>fact</>: <c1>\\1</c1> is <c2>\\2</c2>",
                    message,
                )
            else:
                message = re.sub(
                    r"(?<=: )(.+?) \((.+?)\)", "<c1>\\1</c1> (<c2>\\2</c2>)", message
                )
                message = f"<fg=blue>fact</>: {message.split('fact: ')[1]}"
        elif message.startswith("selecting "):
            message = re.sub(
                r"selecting (.+?) \((.+?)\)",
                "<fg=blue>selecting</> <c1>\\1</c1> (<c2>\\2</c2>)",
                message,
            )
        elif message.startswith("derived:"):
            m = re.match(r"derived: (.+?) \((.+?)\)$", message)
            if m:
                message = (
                    f"<fg=blue>derived</>: <c1>{m.group(1)}</c1>"
                    f" (<c2>{m.group(2)}</c2>)"
                )
            else:
                message = (
                    f"<fg=blue>derived</>: <c1>{message.split('derived: ')[1]}</c1>"
                )
        elif message.startswith("conflict:"):
            m = re.match(r"conflict: (.+?) depends on (.+?) \((.+?)\)", message)
            if m:
                m2 = re.match(r"(.+?) \((.+?)\)", m.group(1))
                if m2:
                    name = m2.group(1)
                    version = f" (<c2>{m2.group(2)}</c2>)"
                else:
                    name = m.group(1)
                    version = ""

                message = (
                    f"<fg=red;options=bold>conflict</>: <c1>{name}</c1>{version} "
                    f"depends on <c1>{m.group(2)}</c1> (<c2>{m.group(3)}</c2>)"
                )
            else:
                message = (
                    "<fg=red;options=bold>conflict</>:"
                    f" {message.split('conflict: ')[1]}"
                )

        message = message.replace("! ", "<error>!</error> ")

        if self.is_debugging():
            debug_info = str(message)
            debug_info = (
                "\n".join(
                    [
                        f"<debug>{str(depth).rjust(4)}:</debug> {s}"
                        for s in debug_info.split("\n")
                    ]
                )
                + "\n"
            )

            self._io.write(debug_info)

    @contextmanager
    def progress(self) -> Iterator[None]:
        if not self._io.output.is_decorated() or self.is_debugging():
            self._io.write_line("Resolving dependencies...")
            yield
        else:
            indicator = Indicator(self._io, "{message} <debug>({elapsed:2s})</debug>")

            with indicator.auto(
                "<info>Resolving dependencies...</info>",
                "<info>Resolving dependencies...</info>",
            ):
                yield

        self._in_progress = False

    def _merge_dependencies_by_constraint(
        self, dependencies: Iterable[Dependency]
    ) -> list[Dependency]:
        by_constraint: dict[VersionConstraint, list[Dependency]] = defaultdict(list)
        for dep in dependencies:
            by_constraint[dep.constraint].append(dep)
        for constraint, _deps in by_constraint.items():
            new_markers = []
            for dep in _deps:
                marker = dep.marker.without_extras()
                if marker.is_any():
                    # No marker or only extras
                    continue

                new_markers.append(marker)

            if not new_markers:
                continue

            dep = _deps[0]
            dep.marker = dep.marker.union(MarkerUnion(*new_markers))
            by_constraint[constraint] = [dep]

        return [value[0] for value in by_constraint.values()]

    def _merge_dependencies_by_marker(
        self, dependencies: Iterable[Dependency]
    ) -> list[Dependency]:
        by_marker: dict[BaseMarker, list[Dependency]] = defaultdict(list)
        for dep in dependencies:
            by_marker[dep.marker].append(dep)
        deps = []
        for _deps in by_marker.values():
            if len(_deps) == 1:
                deps.extend(_deps)
            else:
                new_constraint = _deps[0].constraint
                for dep in _deps[1:]:
                    new_constraint = new_constraint.intersect(dep.constraint)
                if new_constraint.is_empty():
                    # leave dependencies as-is so the resolver will pickup
                    # the conflict and display a proper error.
                    deps.extend(_deps)
                else:
                    self.debug(
                        f"<debug>Merging constraints for {_deps[0].name} for"
                        f" marker {_deps[0].marker}</debug>"
                    )
                    deps.append(_deps[0].with_constraint(new_constraint))
        return deps
