Fix linting errors

Remove unused imports
Disable redundant errors
Add notes for why errors are disabled

.github/scripts/setup-env.sh

@@ -26,7 +26,6 @@ poetry --version --no-ansi;
 poetry run pip --version;
 
 poetry install \
-  --extras poetry \
   --quiet \
   --remove-untracked \
   --no-ansi;

tests/fixtures.py

@@ -1,4 +1,4 @@
-# pylint: disable=missing-module-docstring, missing-function-docstring, unused-argument, too-few-public-methods
+# pylint: disable=missing-module-docstring,missing-function-docstring,unused-argument,too-few-public-methods,protected-access
 import time
 from pathlib import Path
 from typing import List
@@ -10,7 +10,7 @@ import pytest
 import tox.tox_env.python.virtual_env.runner
 from poetry.installation.operations.operation import Operation
 
-from tox_poetry_installer import utilities
+import tox_poetry_installer.hooks._tox_on_install_helpers
 
 
 TEST_PROJECT_PATH = Path(__file__).parent.resolve() / "test-project"
@@ -47,7 +47,11 @@ class MockExecutor:
 
 @pytest.fixture
 def mock_venv(monkeypatch):
-    monkeypatch.setattr(utilities, "convert_virtualenv", lambda venv: venv)
+    monkeypatch.setattr(
+        tox_poetry_installer.hooks._tox_on_install_helpers,
+        "convert_virtualenv",
+        lambda venv: venv,
+    )
     monkeypatch.setattr(poetry.installation.executor, "Executor", MockExecutor)
     monkeypatch.setattr(
         tox.tox_env.python.virtual_env.runner, "VirtualEnvRunner", MockVirtualEnv

tests/test_installer.py

@@ -1,4 +1,4 @@
-# pylint: disable=missing-module-docstring, redefined-outer-name, unused-argument, wrong-import-order, unused-import
+# pylint: disable=missing-module-docstring,redefined-outer-name,unused-argument,unused-import,protected-access
 import time
 from unittest import mock
 
@@ -6,23 +6,24 @@ import pytest
 import tox.tox_env.python.virtual_env.runner
 from poetry.factory import Factory
 
+import tox_poetry_installer.hooks._tox_on_install_helpers
 from .fixtures import mock_poetry_factory
 from .fixtures import mock_venv
-from tox_poetry_installer import installer
-from tox_poetry_installer import utilities
 
 
 def test_deduplication(mock_venv, mock_poetry_factory):
     """Test that the installer does not install duplicate dependencies"""
     poetry = Factory().create_poetry(None)
-    packages: utilities.PackageMap = {
+    packages: tox_poetry_installer.hooks._tox_on_install_helpers.PackageMap = {
         item.name: item for item in poetry.locker.locked_repository().packages
     }
 
     venv = tox.tox_env.python.virtual_env.runner.VirtualEnvRunner()
     to_install = [packages["toml"], packages["toml"]]
 
-    installer.install(poetry, venv, to_install)
+    tox_poetry_installer.hooks._tox_on_install_helpers.install_package(
+        poetry, venv, to_install
+    )
 
     assert len(set(to_install)) == len(venv.installed)  # pylint: disable=no-member
 
@@ -30,7 +31,7 @@ def test_deduplication(mock_venv, mock_poetry_factory):
 def test_parallelization(mock_venv, mock_poetry_factory):
     """Test that behavior is consistent between parallel and non-parallel usage"""
     poetry = Factory().create_poetry(None)
-    packages: utilities.PackageMap = {
+    packages: tox_poetry_installer.hooks._tox_on_install_helpers.PackageMap = {
         item.name: item for item in poetry.locker.locked_repository().packages
     }
 
@@ -45,12 +46,16 @@ def test_parallelization(mock_venv, mock_poetry_factory):
 
     venv_sequential = tox.tox_env.python.virtual_env.runner.VirtualEnvRunner()
     start_sequential = time.time()
-    installer.install(poetry, venv_sequential, to_install, 0)
+    tox_poetry_installer.hooks._tox_on_install_helpers.install_package(
+        poetry, venv_sequential, to_install, 0
+    )
     sequential = time.time() - start_sequential
 
     venv_parallel = tox.tox_env.python.virtual_env.runner.VirtualEnvRunner()
     start_parallel = time.time()
-    installer.install(poetry, venv_parallel, to_install, 5)
+    tox_poetry_installer.hooks._tox_on_install_helpers.install_package(
+        poetry, venv_parallel, to_install, 5
+    )
     parallel = time.time() - start_parallel
 
     # The mock delay during package install is static (one second) so these values should all
@@ -72,7 +77,7 @@ def test_propagates_exceptions_during_installation(
     from tox_poetry_installer import _poetry  # pylint: disable=import-outside-toplevel
 
     poetry = Factory().create_poetry(None)
-    packages: utilities.PackageMap = {
+    packages: tox_poetry_installer.hooks._tox_on_install_helpers.PackageMap = {
         item.name: item for item in poetry.locker.locked_repository().packages
     }
     to_install = [packages["toml"]]
@@ -85,6 +90,8 @@ def test_propagates_exceptions_during_installation(
         **{"return_value.execute.side_effect": fake_exception},
     ):
         with pytest.raises(ValueError) as exc_info:
-            installer.install(poetry, venv, to_install, num_threads)
+            tox_poetry_installer.hooks._tox_on_install_helpers.install_package(
+                poetry, venv, to_install, num_threads
+            )
 
     assert exc_info.value is fake_exception

tests/test_transients.py

@@ -1,33 +1,22 @@
-# pylint: disable=missing-module-docstring, redefined-outer-name, unused-argument, wrong-import-order, unused-import
+# pylint: disable=missing-module-docstring,redefined-outer-name,unused-argument,unused-import,protected-access
 import poetry.factory
 import poetry.utils.env
 import pytest
-from poetry.puzzle.provider import Provider
 
+import tox_poetry_installer.hooks._tox_on_install_helpers
 from .fixtures import mock_poetry_factory
 from .fixtures import mock_venv
-from tox_poetry_installer import constants
 from tox_poetry_installer import exceptions
-from tox_poetry_installer import utilities
-
-
-def test_exclude_unsafe():
-    """Test that the unsafe packages are properly excluded
-
-    Also ensure that the internal constant matches the value from Poetry
-    """
-    assert Provider.UNSAFE_PACKAGES == constants.UNSAFE_PACKAGES
-
-    for dep in constants.UNSAFE_PACKAGES:
-        assert not utilities.identify_transients(dep, {}, None)
 
 
 def test_allow_missing():
     """Test that the ``allow_missing`` parameter works as expected"""
     with pytest.raises(exceptions.LockedDepNotFoundError):
-        utilities.identify_transients("luke-skywalker", {}, None)
+        tox_poetry_installer.hooks._tox_on_install_helpers.identify_transients(
+            "luke-skywalker", {}, None
+        )
 
-    assert not utilities.identify_transients(
+    assert not tox_poetry_installer.hooks._tox_on_install_helpers.identify_transients(
         "darth-vader", {}, None, allow_missing=["darth-vader"]
     )
 
@@ -47,7 +36,9 @@ def test_exclude_pep508():
         "=>foo",
     ]:
         with pytest.raises(exceptions.LockedDepVersionConflictError):
-            utilities.identify_transients(version, {}, None)
+            tox_poetry_installer.hooks._tox_on_install_helpers.identify_transients(
+                version, {}, None
+            )
 
 
 def test_functional(mock_poetry_factory, mock_venv):
@@ -57,7 +48,9 @@ def test_functional(mock_poetry_factory, mock_venv):
     is always the last in the returned list.
     """
     pypoetry = poetry.factory.Factory().create_poetry(None)
-    packages = utilities.build_package_map(pypoetry)
+    packages = tox_poetry_installer.hooks._tox_on_install_helpers.build_package_map(
+        pypoetry
+    )
     venv = poetry.utils.env.VirtualEnv()  # pylint: disable=no-value-for-parameter
 
     requests_requires = [
@@ -68,12 +61,18 @@ def test_functional(mock_poetry_factory, mock_venv):
         packages["requests"][0],
     ]
 
-    transients = utilities.identify_transients("requests", packages, venv)
+    transients = tox_poetry_installer.hooks._tox_on_install_helpers.identify_transients(
+        "requests", packages, venv
+    )
 
     assert all((item in requests_requires) for item in transients)
     assert all((item in transients) for item in requests_requires)
 
     for package in [packages["requests"][0], packages["tox"][0], packages["flask"][0]]:
-        transients = utilities.identify_transients(package.name, packages, venv)
+        transients = (
+            tox_poetry_installer.hooks._tox_on_install_helpers.identify_transients(
+                package.name, packages, venv
+            )
+        )
         assert transients[-1] == package
         assert len(transients) == len(set(transients))

tox.ini

@@ -6,8 +6,6 @@ skip_missing_interpreters = true
 description = Run the tests
 require_locked_deps = true
 require_poetry = true
-extras =
-    poetry
 locked_deps =
     pytest
     pytest-cov

tox_poetry_installer/_poetry.py

@@ -21,13 +21,13 @@ at the module scope it is imported into function scope wherever Poetry component
 moves import errors from load time to runtime which allows the plugin to be skipped if Poetry isn't
 installed and/or a more helpful error be raised within the Tox framework.
 """
-# pylint: disable=unused-import
 import sys
 
 from tox_poetry_installer import exceptions
 
 
 try:
+    # pylint: disable=import-outside-toplevel,unused-import
     from cleo.io.null_io import NullIO
     from poetry.config.config import Config
     from poetry.core.packages.dependency import Dependency as PoetryDependency

tox_poetry_installer/constants.py

@@ -5,7 +5,6 @@ in this module.
 
 All constants should be type hinted.
 """
-from typing import Set
 from typing import Tuple
 
 from tox_poetry_installer import __about__

tox_poetry_installer/exceptions.py

@@ -11,6 +11,7 @@ All exceptions should inherit from the common base exception :exc:`ToxPoetryInst
    +-- LockedDepNotFoundError
    +-- ExtraNotFoundError
    +-- LockedDepsRequiredError
+   +-- LockfileParsingError
 
 """
 
@@ -41,3 +42,7 @@ class ExtraNotFoundError(ToxPoetryInstallerException):
 
 class LockedDepsRequiredError(ToxPoetryInstallerException):
     """Environment cannot specify unlocked dependencies when locked dependencies are required"""
+
+
+class LockfileParsingError(ToxPoetryInstallerException):
+    """Failed to load or parse the Poetry lockfile"""

tox_poetry_installer/hooks/_tox_on_install_helpers.py

@@ -0,0 +1,349 @@
+"""Helper functions for the :func:`tox_on_install` hook"""
+import collections
+import concurrent.futures
+import contextlib
+import typing
+from datetime import datetime
+from pathlib import Path
+from typing import Collection
+from typing import Dict
+from typing import List
+from typing import Sequence
+from typing import Set
+
+from poetry.core.packages.dependency import Dependency as PoetryDependency
+from poetry.core.packages.package import Package as PoetryPackage
+from tox.tox_env.api import ToxEnv as ToxVirtualEnv
+from tox.tox_env.package import PackageToxEnv
+
+from tox_poetry_installer import constants
+from tox_poetry_installer import exceptions
+from tox_poetry_installer import logger
+
+if typing.TYPE_CHECKING:
+    from tox_poetry_installer import _poetry
+
+# This is globally disabled to support the usage of the _poetry shadow module
+# pylint: disable=import-outside-toplevel
+
+
+PackageMap = Dict[str, List[PoetryPackage]]
+
+
+def check_preconditions(venv: ToxVirtualEnv) -> "_poetry.Poetry":
+    """Check that the local project environment meets expectations"""
+
+    # Skip running the plugin for the provisioning environment. The provisioned environment,
+    # for alternative Tox versions and/or the ``requires`` meta dependencies is specially
+    # handled by Tox and is out of scope for this plugin. Since one of the ways to install this
+    # plugin in the first place is via the Tox provisioning environment, it quickly becomes a
+    # chicken-and-egg problem.
+    if isinstance(venv, PackageToxEnv):
+        raise exceptions.SkipEnvironment(f"Skipping Tox provisioning env '{venv.name}'")
+
+    from tox_poetry_installer import _poetry
+
+    try:
+        return _poetry.Factory().create_poetry(venv.core["tox_root"])
+    # Support running the plugin when the current tox project does not use Poetry for its
+    # environment/dependency management.
+    #
+    # ``RuntimeError`` is dangerous to blindly catch because it can be (and in Poetry's case,
+    # is) raised in many different places for different purposes.
+    except RuntimeError as err:
+        raise exceptions.SkipEnvironment(
+            f"Skipping installation of locked dependencies due to a Poetry error: {err}"
+        ) from None
+
+
+def identify_transients(
+    dep_name: str,
+    packages: PackageMap,
+    venv: "_poetry.VirtualEnv",
+    allow_missing: Sequence[str] = (),
+) -> List[PoetryPackage]:
+    """Using a pool of packages, identify all transient dependencies of a given package name
+
+    :param dep_name: Either the Poetry dependency or the dependency's bare package name to recursively
+                     identify the transient dependencies of
+    :param packages: All packages from the lockfile to use for identifying dependency relationships.
+    :param venv: Poetry virtual environment to use for package compatibility checks
+    :param allow_missing: Sequence of package names to allow to be missing from the lockfile. Any
+                          packages that are not found in the lockfile but their name appears in this
+                          list will be silently skipped from installation.
+    :returns: List of packages that need to be installed for the requested dependency.
+
+    .. note:: The package corresponding to the dependency specified by the ``dep`` parameter will
+              be included in the returned list of packages.
+    """
+    searched: Set[str] = set()
+
+    def _transients(transient: PoetryDependency) -> List[PoetryPackage]:
+        searched.add(transient.name)
+
+        results: List[PoetryPackage] = []
+        for option in packages[transient.name]:
+            if venv.is_valid_for_marker(option.to_dependency().marker):
+                for requirement in option.requires:
+                    if requirement.name not in searched:
+                        results += _transients(requirement)
+                logger.debug(f"Including {option} for installation")
+                results.append(option)
+                break
+        else:
+            logger.debug(
+                f"Skipping {transient.name}: target python version is {'.'.join([str(item) for item in venv.get_version_info()])} but package requires {transient.marker}"
+            )
+
+        return results
+
+    try:
+        for option in packages[dep_name]:
+            if venv.is_valid_for_marker(option.to_dependency().marker):
+                dep = option.to_dependency()
+                break
+        else:
+            logger.warning(
+                f"Skipping {dep_name}: no locked version found compatible with target python version {'.'.join([str(item) for item in venv.get_version_info()])}"
+            )
+            return []
+
+        return _transients(dep)
+    except KeyError as err:
+        missing = err.args[0]
+
+        if missing in allow_missing:
+            logger.debug(f"Skipping {missing}: package is allowed to be unlocked")
+            return []
+
+        if any(
+            delimiter in missing for delimiter in constants.PEP508_VERSION_DELIMITERS
+        ):
+            raise exceptions.LockedDepVersionConflictError(
+                f"Locked dependency '{missing}' cannot include version specifier"
+            ) from None
+
+        raise exceptions.LockedDepNotFoundError(
+            f"No version of locked dependency '{missing}' found in the project lockfile"
+        ) from None
+
+
+def find_project_deps(
+    packages: PackageMap,
+    venv: "_poetry.VirtualEnv",
+    poetry: "_poetry.Poetry",
+    extras: Sequence[str] = (),
+) -> List[PoetryPackage]:
+    """Find the root project dependencies
+
+    Recursively identify the dependencies of the root project package
+
+    :param packages: Mapping of all locked package names to their corresponding package object
+    :param venv: Poetry virtual environment to use for package compatibility checks
+    :param poetry: Poetry object for the current project
+    :param extras: Sequence of extra names to include the dependencies of
+    """
+
+    required_dep_names = [
+        item.name for item in poetry.package.requires if not item.is_optional()
+    ]
+
+    extra_dep_names: List[str] = []
+    for extra in extras:
+        logger.info(f"Processing project extra '{extra}'")
+        try:
+            extra_dep_names += [item.name for item in poetry.package.extras[extra]]
+        except KeyError:
+            raise exceptions.ExtraNotFoundError(
+                f"Environment specifies project extra '{extra}' which was not found in the lockfile"
+            ) from None
+
+    dependencies: List[PoetryPackage] = []
+    for dep_name in required_dep_names + extra_dep_names:
+        dependencies += identify_transients(
+            dep_name.lower(), packages, venv, allow_missing=[poetry.package.name]
+        )
+
+    return dedupe_packages(dependencies)
+
+
+def find_additional_deps(
+    packages: PackageMap,
+    venv: "_poetry.VirtualEnv",
+    poetry: "_poetry.Poetry",
+    dep_names: Sequence[str],
+) -> List[PoetryPackage]:
+    """Find additional dependencies
+
+    Recursively identify the dependencies of an arbitrary list of package names
+
+    :param packages: Mapping of all locked package names to their corresponding package object
+    :param venv: Poetry virtual environment to use for package compatibility checks
+    :param poetry: Poetry object for the current project
+    :param dep_names: Sequence of additional dependency names to recursively find the transient
+                      dependencies for
+    """
+    dependencies: List[PoetryPackage] = []
+    for dep_name in dep_names:
+        dependencies += identify_transients(
+            dep_name.lower(), packages, venv, allow_missing=[poetry.package.name]
+        )
+
+    return dedupe_packages(dependencies)
+
+
+def find_group_deps(
+    group: str,
+    packages: PackageMap,
+    venv: "_poetry.VirtualEnv",
+    poetry: "_poetry.Poetry",
+) -> List[PoetryPackage]:
+    """Find the dependencies belonging to a dependency group
+
+    Recursively identify the Poetry dev dependencies
+
+    :param group: Name of the dependency group from the project's ``pyproject.toml``
+    :param packages: Mapping of all locked package names to their corresponding package object
+    :param venv: Poetry virtual environment to use for package compatibility checks
+    :param poetry: Poetry object for the current project
+    """
+    return find_additional_deps(
+        packages,
+        venv,
+        poetry,
+        poetry.pyproject.data["tool"]["poetry"]
+        .get("group", {})
+        .get(group, {})
+        .get("dependencies", {})
+        .keys(),
+    )
+
+
+def find_dev_deps(
+    packages: PackageMap, venv: "_poetry.VirtualEnv", poetry: "_poetry.Poetry"
+) -> List[PoetryPackage]:
+    """Find the dev dependencies
+
+    Recursively identify the Poetry dev dependencies
+
+    :param packages: Mapping of all locked package names to their corresponding package object
+    :param venv: Poetry virtual environment to use for package compatibility checks
+    :param poetry: Poetry object for the current project
+    """
+    dev_group_deps = find_group_deps("dev", packages, venv, poetry)
+
+    # Legacy pyproject.toml poetry format:
+    legacy_dev_group_deps = find_additional_deps(
+        packages,
+        venv,
+        poetry,
+        poetry.pyproject.data["tool"]["poetry"].get("dev-dependencies", {}).keys(),
+    )
+
+    # Poetry 1.2 unions these two toml sections.
+    return dedupe_packages(dev_group_deps + legacy_dev_group_deps)
+
+
+def install_package(
+    poetry: "_poetry.Poetry",
+    venv: ToxVirtualEnv,
+    packages: Collection["_poetry.PoetryPackage"],
+    parallels: int = 0,
+):
+    """Install a bunch of packages to a virtualenv
+
+    :param poetry: Poetry object the packages were sourced from
+    :param venv: Tox virtual environment to install the packages to
+    :param packages: List of packages to install to the virtual environment
+    :param parallels: Number of parallel processes to use for installing dependency packages, or
+                      ``None`` to disable parallelization.
+    """
+    from tox_poetry_installer import _poetry
+
+    logger.info(f"Installing {len(packages)} packages to environment at {venv.env_dir}")
+
+    install_executor = _poetry.Executor(
+        env=convert_virtualenv(venv),
+        io=_poetry.NullIO(),
+        pool=poetry.pool,
+        config=_poetry.Config(),
+    )
+
+    installed: Set[_poetry.PoetryPackage] = set()
+
+    def logged_install(dependency: _poetry.PoetryPackage) -> None:
+        start = datetime.now()
+        logger.debug(f"Installing {dependency}")
+        install_executor.execute([_poetry.Install(package=dependency)])
+        end = datetime.now()
+        logger.debug(f"Finished installing {dependency} in {end - start}")
+
+    @contextlib.contextmanager
+    def _optional_parallelize():
+        """A bit of cheat, really
+
+        A context manager that exposes a common interface for the caller that optionally
+        enables/disables the usage of the parallel thread pooler depending on the value of
+        the ``parallels`` parameter.
+        """
+        if parallels > 0:
+            with concurrent.futures.ThreadPoolExecutor(
+                max_workers=parallels
+            ) as executor:
+                yield executor.submit
+        else:
+            yield lambda func, arg: func(arg)
+
+    with _optional_parallelize() as executor:
+        futures = []
+        for dependency in packages:
+            if dependency not in installed:
+                installed.add(dependency)
+                logger.debug(f"Queuing {dependency}")
+                future = executor(logged_install, dependency)
+                if future is not None:
+                    futures.append(future)
+            else:
+                logger.debug(f"Skipping {dependency}, already installed")
+        logger.debug("Waiting for installs to finish...")
+
+        for future in concurrent.futures.as_completed(futures):
+            # Don't actually care about the return value, just waiting on the
+            # future to ensure any exceptions that were raised in the called
+            # function are propagated.
+            future.result()
+
+
+def dedupe_packages(packages: Sequence[PoetryPackage]) -> List[PoetryPackage]:
+    """Deduplicates a sequence of PoetryPackages while preserving ordering
+
+    Adapted from StackOverflow: https://stackoverflow.com/a/480227
+    """
+    seen: Set[PoetryPackage] = set()
+    # Make this faster, avoid method lookup below
+    seen_add = seen.add
+    return [p for p in packages if not (p in seen or seen_add(p))]
+
+
+def convert_virtualenv(venv: ToxVirtualEnv) -> "_poetry.VirtualEnv":
+    """Convert a Tox venv to a Poetry venv
+
+    :param venv: Tox ``VirtualEnv`` object representing a tox virtual environment
+    :returns: Poetry ``VirtualEnv`` object representing a poetry virtual environment
+    """
+    from tox_poetry_installer import _poetry
+
+    return _poetry.VirtualEnv(path=Path(venv.env_dir))
+
+
+def build_package_map(poetry: "_poetry.Poetry") -> PackageMap:
+    """Build the mapping of package names to objects
+
+    :param poetry: Populated poetry object to load locked packages from
+    :returns: Mapping of package names to Poetry package objects
+    """
+    packages = collections.defaultdict(list)
+    for package in poetry.locker.locked_repository().packages:
+        packages[package.name].append(package)
+
+    return packages

tox_poetry_installer/hooks/tox_add_env_config.py

@@ -5,8 +5,11 @@ from tox.config.sets import EnvConfigSet
 from tox.plugin import impl
 
 
+# pylint: disable=missing-function-docstring
 @impl
-def tox_add_env_config(env_conf: EnvConfigSet):
+def tox_add_env_config(
+    env_conf: EnvConfigSet,
+):
     env_conf.add_config(
         "poetry_dep_groups",
         of_type=List[str],

tox_poetry_installer/hooks/tox_add_option.py

@@ -5,6 +5,7 @@ from tox.plugin import impl
 from tox_poetry_installer import constants
 
 
+# pylint: disable=missing-function-docstring
 @impl
 def tox_add_option(parser: ToxParser):
     parser.add_argument(

tox_poetry_installer/hooks/tox_on_install.py

@@ -4,40 +4,26 @@ Loads the local Poetry environment and the corresponding lockfile then pulls the
 specified by the Tox environment. Finally these dependencies are installed into the Tox
 environment using the Poetry ``PipInstaller`` backend.
 """
-import collections
-import concurrent.futures
-import contextlib
-import typing
-from datetime import datetime
 from itertools import chain
-from pathlib import Path
-from typing import Collection
-from typing import Dict
-from typing import List
-from typing import Sequence
-from typing import Set
 
-from poetry.core.packages.dependency import Dependency as PoetryDependency
-from poetry.core.packages.package import Package as PoetryPackage
 from tox.plugin import impl
 from tox.tox_env.api import ToxEnv as ToxVirtualEnv
-from tox.tox_env.package import PackageToxEnv
 
-from tox_poetry_installer import constants
 from tox_poetry_installer import exceptions
 from tox_poetry_installer import logger
-
-if typing.TYPE_CHECKING:
-    from tox_poetry_installer import _poetry
-
-
-PackageMap = Dict[str, List[PoetryPackage]]
+from tox_poetry_installer.hooks._tox_on_install_helpers import build_package_map
+from tox_poetry_installer.hooks._tox_on_install_helpers import check_preconditions
+from tox_poetry_installer.hooks._tox_on_install_helpers import convert_virtualenv
+from tox_poetry_installer.hooks._tox_on_install_helpers import dedupe_packages
+from tox_poetry_installer.hooks._tox_on_install_helpers import find_additional_deps
+from tox_poetry_installer.hooks._tox_on_install_helpers import find_group_deps
+from tox_poetry_installer.hooks._tox_on_install_helpers import find_project_deps
+from tox_poetry_installer.hooks._tox_on_install_helpers import install_package
 
 
+# pylint: disable=missing-function-docstring,unused-argument
 @impl
-def tox_on_install(
-    tox_env: ToxVirtualEnv, section: str  # pylint: disable=unused-argument
-) -> None:
+def tox_on_install(tox_env: ToxVirtualEnv, *args) -> None:
     try:
         poetry = check_preconditions(tox_env)
     except exceptions.SkipEnvironment as err:
@@ -54,10 +40,16 @@ def tox_on_install(
 
     virtualenv = convert_virtualenv(tox_env)
 
+    try:
         if not poetry.locker.is_fresh():
             logger.warning(
                 f"The Poetry lock file is not up to date with the latest changes in {poetry.file}"
             )
+    except FileNotFoundError as err:
+        logger.error(f"Could not parse lockfile: {err}")
+        raise exceptions.LockfileParsingError(
+            f"Could not parse lockfile: {err}"
+        ) from err
 
     try:
         if tox_env.conf["require_locked_deps"] and tox_env.conf["deps"].lines():
@@ -119,322 +111,3 @@ def tox_on_install(
         dependencies,
         tox_env.options.parallel_install_threads,
     )
-
-
-def check_preconditions(venv: ToxVirtualEnv) -> "_poetry.Poetry":
-    """Check that the local project environment meets expectations"""
-
-    # Skip running the plugin for the provisioning environment. The provisioned environment,
-    # for alternative Tox versions and/or the ``requires`` meta dependencies is specially
-    # handled by Tox and is out of scope for this plugin. Since one of the ways to install this
-    # plugin in the first place is via the Tox provisioning environment, it quickly becomes a
-    # chicken-and-egg problem.
-    if isinstance(venv, PackageToxEnv):
-        raise exceptions.SkipEnvironment(f"Skipping Tox provisioning env '{venv.name}'")
-
-    from tox_poetry_installer import _poetry
-
-    try:
-        return _poetry.Factory().create_poetry(venv.core["tox_root"])
-    # Support running the plugin when the current tox project does not use Poetry for its
-    # environment/dependency management.
-    #
-    # ``RuntimeError`` is dangerous to blindly catch because it can be (and in Poetry's case,
-    # is) raised in many different places for different purposes.
-    except RuntimeError as err:
-        raise exceptions.SkipEnvironment(
-            f"Skipping installation of locked dependencies due to a Poetry error: {err}"
-        ) from None
-
-
-def identify_transients(
-    dep_name: str,
-    packages: PackageMap,
-    venv: "_poetry.VirtualEnv",
-    allow_missing: Sequence[str] = (),
-) -> List[PoetryPackage]:
-    """Using a pool of packages, identify all transient dependencies of a given package name
-
-    :param dep_name: Either the Poetry dependency or the dependency's bare package name to recursively
-                     identify the transient dependencies of
-    :param packages: All packages from the lockfile to use for identifying dependency relationships.
-    :param venv: Poetry virtual environment to use for package compatibility checks
-    :param allow_missing: Sequence of package names to allow to be missing from the lockfile. Any
-                          packages that are not found in the lockfile but their name appears in this
-                          list will be silently skipped from installation.
-    :returns: List of packages that need to be installed for the requested dependency.
-
-    .. note:: The package corresponding to the dependency specified by the ``dep`` parameter will
-              be included in the returned list of packages.
-    """
-    searched: Set[str] = set()
-
-    def _transients(transient: PoetryDependency) -> List[PoetryPackage]:
-        searched.add(transient.name)
-
-        results: List[PoetryPackage] = []
-        for option in packages[transient.name]:
-            if venv.is_valid_for_marker(option.to_dependency().marker):
-                for requirement in option.requires:
-                    if requirement.name not in searched:
-                        results += _transients(requirement)
-                logger.debug(f"Including {option} for installation")
-                results.append(option)
-                break
-        else:
-            logger.debug(
-                f"Skipping {transient.name}: target python version is {'.'.join([str(item) for item in venv.get_version_info()])} but package requires {transient.marker}"
-            )
-
-        return results
-
-    try:
-        for option in packages[dep_name]:
-            if venv.is_valid_for_marker(option.to_dependency().marker):
-                dep = option.to_dependency()
-                break
-        else:
-            logger.warning(
-                f"Skipping {dep_name}: no locked version found compatible with target python version {'.'.join([str(item) for item in venv.get_version_info()])}"
-            )
-            return []
-
-        return _transients(dep)
-    except KeyError as err:
-        missing = err.args[0]
-
-        if missing in allow_missing:
-            logger.debug(f"Skipping {missing}: package is allowed to be unlocked")
-            return []
-
-        if any(
-            delimiter in missing for delimiter in constants.PEP508_VERSION_DELIMITERS
-        ):
-            raise exceptions.LockedDepVersionConflictError(
-                f"Locked dependency '{missing}' cannot include version specifier"
-            ) from None
-
-        raise exceptions.LockedDepNotFoundError(
-            f"No version of locked dependency '{missing}' found in the project lockfile"
-        ) from None
-
-
-def find_project_deps(
-    packages: PackageMap,
-    venv: "_poetry.VirtualEnv",
-    poetry: "_poetry.Poetry",
-    extras: Sequence[str] = (),
-) -> List[PoetryPackage]:
-    """Find the root project dependencies
-
-    Recursively identify the dependencies of the root project package
-
-    :param packages: Mapping of all locked package names to their corresponding package object
-    :param venv: Poetry virtual environment to use for package compatibility checks
-    :param poetry: Poetry object for the current project
-    :param extras: Sequence of extra names to include the dependencies of
-    """
-
-    required_dep_names = [
-        item.name for item in poetry.package.requires if not item.is_optional()
-    ]
-
-    extra_dep_names: List[str] = []
-    for extra in extras:
-        logger.info(f"Processing project extra '{extra}'")
-        try:
-            extra_dep_names += [item.name for item in poetry.package.extras[extra]]
-        except KeyError:
-            raise exceptions.ExtraNotFoundError(
-                f"Environment specifies project extra '{extra}' which was not found in the lockfile"
-            ) from None
-
-    dependencies: List[PoetryPackage] = []
-    for dep_name in required_dep_names + extra_dep_names:
-        dependencies += identify_transients(
-            dep_name.lower(), packages, venv, allow_missing=[poetry.package.name]
-        )
-
-    return dedupe_packages(dependencies)
-
-
-def find_additional_deps(
-    packages: PackageMap,
-    venv: "_poetry.VirtualEnv",
-    poetry: "_poetry.Poetry",
-    dep_names: Sequence[str],
-) -> List[PoetryPackage]:
-    """Find additional dependencies
-
-    Recursively identify the dependencies of an arbitrary list of package names
-
-    :param packages: Mapping of all locked package names to their corresponding package object
-    :param venv: Poetry virtual environment to use for package compatibility checks
-    :param poetry: Poetry object for the current project
-    :param dep_names: Sequence of additional dependency names to recursively find the transient
-                      dependencies for
-    """
-    dependencies: List[PoetryPackage] = []
-    for dep_name in dep_names:
-        dependencies += identify_transients(
-            dep_name.lower(), packages, venv, allow_missing=[poetry.package.name]
-        )
-
-    return dedupe_packages(dependencies)
-
-
-def find_group_deps(
-    group: str,
-    packages: PackageMap,
-    venv: "_poetry.VirtualEnv",
-    poetry: "_poetry.Poetry",
-) -> List[PoetryPackage]:
-    """Find the dependencies belonging to a dependency group
-
-    Recursively identify the Poetry dev dependencies
-
-    :param group: Name of the dependency group from the project's ``pyproject.toml``
-    :param packages: Mapping of all locked package names to their corresponding package object
-    :param venv: Poetry virtual environment to use for package compatibility checks
-    :param poetry: Poetry object for the current project
-    """
-    return find_additional_deps(
-        packages,
-        venv,
-        poetry,
-        poetry.pyproject.data["tool"]["poetry"]
-        .get("group", {})
-        .get(group, {})
-        .get("dependencies", {})
-        .keys(),
-    )
-
-
-def find_dev_deps(
-    packages: PackageMap, venv: "_poetry.VirtualEnv", poetry: "_poetry.Poetry"
-) -> List[PoetryPackage]:
-    """Find the dev dependencies
-
-    Recursively identify the Poetry dev dependencies
-
-    :param packages: Mapping of all locked package names to their corresponding package object
-    :param venv: Poetry virtual environment to use for package compatibility checks
-    :param poetry: Poetry object for the current project
-    """
-    dev_group_deps = find_group_deps("dev", packages, venv, poetry)
-
-    # Legacy pyproject.toml poetry format:
-    legacy_dev_group_deps = find_additional_deps(
-        packages,
-        venv,
-        poetry,
-        poetry.pyproject.data["tool"]["poetry"].get("dev-dependencies", {}).keys(),
-    )
-
-    # Poetry 1.2 unions these two toml sections.
-    return dedupe_packages(dev_group_deps + legacy_dev_group_deps)
-
-
-def install_package(
-    poetry: "_poetry.Poetry",
-    venv: ToxVirtualEnv,
-    packages: Collection["_poetry.PoetryPackage"],
-    parallels: int = 0,
-):
-    """Install a bunch of packages to a virtualenv
-
-    :param poetry: Poetry object the packages were sourced from
-    :param venv: Tox virtual environment to install the packages to
-    :param packages: List of packages to install to the virtual environment
-    :param parallels: Number of parallel processes to use for installing dependency packages, or
-                      ``None`` to disable parallelization.
-    """
-    from tox_poetry_installer import _poetry
-
-    logger.info(f"Installing {len(packages)} packages to environment at {venv.env_dir}")
-
-    install_executor = _poetry.Executor(
-        env=convert_virtualenv(venv),
-        io=_poetry.NullIO(),
-        pool=poetry.pool,
-        config=_poetry.Config(),
-    )
-
-    installed: Set[_poetry.PoetryPackage] = set()
-
-    def logged_install(dependency: _poetry.PoetryPackage) -> None:
-        start = datetime.now()
-        logger.debug(f"Installing {dependency}")
-        install_executor.execute([_poetry.Install(package=dependency)])
-        end = datetime.now()
-        logger.debug(f"Finished installing {dependency} in {end - start}")
-
-    @contextlib.contextmanager
-    def _optional_parallelize():
-        """A bit of cheat, really
-
-        A context manager that exposes a common interface for the caller that optionally
-        enables/disables the usage of the parallel thread pooler depending on the value of
-        the ``parallels`` parameter.
-        """
-        if parallels > 0:
-            with concurrent.futures.ThreadPoolExecutor(
-                max_workers=parallels
-            ) as executor:
-                yield executor.submit
-        else:
-            yield lambda func, arg: func(arg)
-
-    with _optional_parallelize() as executor:
-        futures = []
-        for dependency in packages:
-            if dependency not in installed:
-                installed.add(dependency)
-                logger.debug(f"Queuing {dependency}")
-                future = executor(logged_install, dependency)
-                if future is not None:
-                    futures.append(future)
-            else:
-                logger.debug(f"Skipping {dependency}, already installed")
-        logger.debug("Waiting for installs to finish...")
-
-        for future in concurrent.futures.as_completed(futures):
-            # Don't actually care about the return value, just waiting on the
-            # future to ensure any exceptions that were raised in the called
-            # function are propagated.
-            future.result()
-
-
-def dedupe_packages(packages: Sequence[PoetryPackage]) -> List[PoetryPackage]:
-    """Deduplicates a sequence of PoetryPackages while preserving ordering
-
-    Adapted from StackOverflow: https://stackoverflow.com/a/480227
-    """
-    seen: Set[PoetryPackage] = set()
-    # Make this faster, avoid method lookup below
-    seen_add = seen.add
-    return [p for p in packages if not (p in seen or seen_add(p))]
-
-
-def convert_virtualenv(venv: ToxVirtualEnv) -> "_poetry.VirtualEnv":
-    """Convert a Tox venv to a Poetry venv
-
-    :param venv: Tox ``VirtualEnv`` object representing a tox virtual environment
-    :returns: Poetry ``VirtualEnv`` object representing a poetry virtual environment
-    """
-    from tox_poetry_installer import _poetry
-
-    return _poetry.VirtualEnv(path=Path(venv.env_dir))
-
-
-def build_package_map(poetry: "_poetry.Poetry") -> PackageMap:
-    """Build the mapping of package names to objects
-
-    :param poetry: Populated poetry object to load locked packages from
-    :returns: Mapping of package names to Poetry package objects
-    """
-    packages = collections.defaultdict(list)
-    for package in poetry.locker.locked_repository().packages:
-        packages[package.name].append(package)
-
-    return packages