Bump patch version

Fix always logging post-sorted unlocked env dependencies

README.md

@@ -11,9 +11,11 @@ dependencies to be installed using [Poetry](https://python-poetry.org/) using it
 
 **Documentation**
 
-* [Installation and Usage](#installation-and-usage)
+* [Installation](#installation)
-* [Limitations](#limitations)
+* [Quick Start](#quick-start)
-* [Why would I use this?](#what-problems-does-this-solve) (What problems does this solve?)
+* [Usage](#usage)
+* [Known Drawbacks and Problems](#known-drawbacks-and-problems)
+* [Why would I use this?](#why-would-i-use-this) (What problems does this solve?)
 * [Developing](#developing)
 * [Contributing](#contributing)
 * [Roadmap](#roadmap)
@@ -26,62 +28,237 @@ Related resources:
 * [Tox plugins](https://tox.readthedocs.io/en/latest/plugins.html)
 
 
-## Installation and Usage
+## Installation
 
-1. Install the plugin from PyPI:
+Add the plugin as a development dependency a project using Poetry:
 
 ```
-poetry add tox-poetry-installer --dev
+~ $: poetry add tox-poetry-installer --dev
 ```
 
-2. Remove all version specifications from the environment dependencies in `tox.ini`:
+Confirm that the plugin is installed, and Tox recognizes it, by checking the Tox version:
+
+```
+~ $: poetry run tox --version
+3.20.0 imported from .venv/lib64/python3.8/site-packages/tox/__init__.py
+registered plugins:
+    tox-poetry-installer-0.2.0 at .venv/lib64/python3.8/site-packages/tox_poetry_installer.py
+```
+
+If using in a CI/automation environment using Pip, ensure that the plugin is installed to the
+same environment as Tox:
+
+```
+# Calling the virtualenv's 'pip' binary directly will cause pip to install to that virtualenv
+~ $: /path/to/my/automation/virtualenv/bin/pip install tox
+~ $: /path/to/my/automation/virtualenv/bin/pip install tox-poetry-installer
+```
+
+
+## Quick Start
+
+To require a Tox environment install all it's dependencies from the Poetry lockfile, add the
+`require_locked_deps = true` option to the environment configuration and remove all version
+specifiers from the dependency list. The versions to install will be taken from the lockfile
+directly:
 
 ```ini
-# This...
 [testenv]
-description = My cool test environment
+description = Run the tests
+require_locked_deps = true
 deps =
-    requests >=2.19,<3.0
-    toml == 0.10.0
-    pytest >=5.4
-
-# ...becomes this:
-[testenv]
-description = My cool test environment
-deps =
-    requests
-    toml
     pytest
+    pytest-cov
+    black
+    pylint
+    mypy
+commands = ...
 ```
 
-3. Run Tox with the `--recreate` flag to rebuild the test environments:
+To require specific dependencies be installed from the Poetry lockfile, and let the rest be
+installed using the default Tox installation method, add the suffix `@poetry` to the dependencies.
+In the example below the `pytest`, `pytest-cov`, and `black` dependencies will be installed using
+the lockfile while `pylint` and `mypy` will be installed using the versions specified here:
 
-```
+```ini
-poetry run tox --recreate
+[testenv]
+description = Run the tests
+require_locked_deps = true
+deps =
+    pytest@poetry
+    pytest-cov@poetry
+    black@poetry
+    pylint >=2.5.0
+    mypy == 0.770
+commands = ...
 ```
 
-4. 💸 Profit 💸
+**Note:** Regardless of the settings outlined above, all dependencies of the project package (the
+one Tox is testing) will always be installed from the lockfile.
 
 
-## Limitations
+## Usage
 
-* In general, any command line or INI settings that affect how Tox installs environment
+After installing the plugin to a project, your Tox automation is already benefiting from the
-  dependencies will be disabled by installing this plugin. A non-exhaustive and untested
+lockfile: when Tox installs your project package to one of your environments, all the dependencies
-  list of the INI options that are not expected to work with this plugin is below:
+of your project package will be installed using the versions specified in the lockfile. This
+happens automatically and requires no configuration changes.
+
+But what about the rest of your Tox environment dependencies?
+
+Let's use an example `tox.ini` file, below, that defines two environments: the main `testenv` for
+running the project tests and `testenv:check` for running some other helpful checks:
+
+```ini
+[tox]
+envlist = py37, static
+isolated_build = true
+
+[testenv]
+description = Run the tests
+deps =
+    pytest == 5.3.0
+commands = ...
+
+[testenv:check]
+description = Static formatting and quality enforcement
+deps =
+    pylint >=2.4.4,<2.6.0
+    mypy == 0.770
+    black --pre
+commands = ...
+```
+
+Let's focus on the `testenv:check` environment first. In this project there's no reason that any
+of these tools should be a different version than what a human developer is using when installing
+from the lockfile. We can require that these dependencies be installed from the lockfile by adding
+the option `require_locked_deps = true` to the environment config, but this will cause an error:
+
+```ini
+[testenv:check]
+description = Static formatting and quality enforcement
+require_locked_deps = true
+deps =
+    pylint >=2.4.4,<2.6.0
+    mypy == 0.770
+    black --pre
+commands = ...
+```
+
+Running Tox using this config gives us this error:
+
+```
+tox_poetry_installer.LockedDepVersionConflictError: Locked dependency 'pylint >=2.4.4,<2.6.0' cannot include version specifier
+```
+
+This is because we told the Tox environment to require all dependencies to be locked, but then also
+specified a specific version constraint for Pylint. With the `require_locked_deps = true` setting
+Tox expects all dependencies to take their version from the lockfile, so when it got conflicting
+information it errors. We can fix this by simply removing all version specifiers from the
+environment dependency list:
+
+```ini
+[testenv:check]
+description = Static formatting and quality enforcement
+require_locked_deps = true
+deps =
+    pylint
+    mypy
+    black
+commands = ...
+```
+
+Now all the dependencies will be installed from the lockfile. If Poetry updates the lockfile with
+a new version then that updated version will be automatically installed when the Tox environment is
+recreated.
+
+Now let's look at the `testenv` environment. Let's make the same changes to the `testenv`
+environment that we made to `testenv:check` above; remove the PyTest version and add
+`require_locked_deps = true`. Then imagine that we want to add a new (made up) tool the test
+environment called `crash_override` to the environment: we can add `crash-override` as a dependency
+of the test environment, but this will cause an error:
+
+```ini
+[testenv]
+description = Run the tests
+require_locked_deps = true
+deps =
+    pytest
+    crash-override
+commands = ...
+```
+
+Running Tox with this config gives us this error:
+
+```
+tox_poetry_installer.LockedDepNotFoundError: No version of locked dependency 'crash-override' found in the project lockfile
+```
+
+This is because `crash-override` is not in our lockfile. Tox will refuse to install a dependency
+that isn't in the lockfile to an an environment that specifies `require_locked_deps = true`. We
+could fix this (if `crash-override` was a real package) by running
+`poetry add crash-override --dev` to add it to the lockfile.
+
+Now let's combine dependencies from the lockfile ("locked dependencies") with dependencies that are
+specified inline in the environment configuration ("unlocked dependencies").
+[This isn't generally recommended of course](#why-would-i-use-this), but it's a valid use case and
+fully supported by this plugin. Let's modify the `testenv` configuration to install PyTest from the
+lockfile but then install an older version of the
+[Requests](https://requests.readthedocs.io/en/master/) library.
+
+The first thing to do is remove the `require_locked_deps = true` setting so that we can install
+Requests as an unlocked dependency. Then we can add our version of requests to the dependency list:
+
+```ini
+[testenv]
+description = Run the tests
+deps =
+    pytest
+    requests >=2.2.0,<2.10.0
+commands = ...
+```
+
+However we still want `pytest` to be installed from the lockfile, so the final step is to tell Tox
+to install it from the lockfile by adding the suffix `@poetry` to it:
+
+```ini
+[testenv]
+description = Run the tests
+deps =
+    pytest@poetry
+    requests >=2.2.0,<2.10.0
+commands = ...
+```
+
+Now when the `testenv` environment is created it will install PyTest (and all of its dependencies)
+from the lockfile while it will install Requests (and all of its dependencies) using the default
+Tox installation backend using Pip.
+
+
+## Known Drawbacks and Problems
+
+* The following `tox.ini` configuration options have no effect on the dependencies installed from
+  the Poetry lockfile (note that they will still affect unlocked dependencies):
   * [`install_command`](https://tox.readthedocs.io/en/latest/config.html#conf-install_command)
   * [`pip_pre`](https://tox.readthedocs.io/en/latest/config.html#conf-pip_pre)
   * [`downloadcache`](https://tox.readthedocs.io/en/latest/config.html#conf-downloadcache) (deprecated)
   * [`download`](https://tox.readthedocs.io/en/latest/config.html#conf-download)
   * [`indexserver`](https://tox.readthedocs.io/en/latest/config.html#conf-indexserver)
   * [`usedevelop`](https://tox.readthedocs.io/en/latest/config.html#conf-indexserver)
-  * [`extras`](https://tox.readthedocs.io/en/latest/config.html#conf-extras)
 
-* When the plugin is enabled all dependencies for all environments will use the Poetry backend
+* The [`extras`](https://tox.readthedocs.io/en/latest/config.html#conf-extras) setting in `tox.ini`
-  provided by the plugin; this functionality cannot be disabled on a per-environment basis.
+  does not work. Optional dependencies of the project package will not be installed to Tox
+  environments. (See the [road map](#roadmap))
 
-* Alternative versions cannot be specified alongside versions from the lockfile. All
+* The plugin currently depends on `poetry<1.1.0`. This can be a different version than Poetry being
-  dependencies are installed from the lockfile and alternative versions cannot be specified
+  used for actual project development. (See the [road map](#roadmap))
-  in the Tox configuration.
+
+* There are a handful of packages that cannot be installed from the lockfile, whether as specific
+  dependencies or as transient dependencies (dependencies of dependencies). This is due to
+  [an ongoing discussion in the Poetry project](https://github.com/python-poetry/poetry/issues/1584);
+  the list of dependencies that cannot be installed from the lockfile can be found
+  [here](https://github.com/python-poetry/poetry/blob/cc8f59a31567f806be868aba880ae0642d49b74e/poetry/puzzle/provider.py#L55).
+  This plugin will skip these dependencies entirely, but log a warning when they are encountered.
 
 
 ## Why would I use this?
@@ -234,6 +411,10 @@ poetry run tox
 All project contributors and participants are expected to adhere to the
 [Contributor Covenant Code of Conduct, Version 2](CODE_OF_CONDUCT.md).
 
+The `devel` branch has the latest (potentially unstable) changes. The
+[tagged versions](https://github.com/enpaul/tox-poetry-installer/releases) correspond to the
+releases on PyPI.
+
 * To report a bug, request a feature, or ask for assistance, please
   [open an issue on the Github repository](https://github.com/enpaul/tox-poetry-installer/issues/new).
 * To report a security concern or code of conduct violation, please contact the project author
@@ -255,11 +436,11 @@ usage in production systems.
 
 ### Path to Beta
 
-- [ ] Verify that primary package dependencies (from the `.package` env) are installed
+- [X] Verify that primary package dependencies (from the `.package` env) are installed
       correctly using the Poetry backend.
 - [ ] Support the [`extras`](https://tox.readthedocs.io/en/latest/config.html#conf-extras)
       Tox configuration option
-- [ ] Add per-environment Tox configuration option to fall back to default installation
+- [X] Add per-environment Tox configuration option to fall back to default installation
       backend.
 - [ ] Add detection of a changed lockfile to automatically trigger a rebuild of Tox
       environments when necessary.
@@ -270,6 +451,7 @@ usage in production systems.
 - [ ] Update to use [poetry-core](https://github.com/python-poetry/poetry-core)
       Tox configuration option) and improve robustness of the Tox and Poetry module imports
       to avoid potentially breaking API changes in upstream packages.
+- [ ] Find and implement a way to mitigate the [Poetry UNSAFE_DEPENDENCIES bug](https://github.com/python-poetry/poetry/issues/1584).
 
 ### Path to Stable
 

poetry.lock

@@ -364,7 +364,7 @@ marker = "python_version >= \"3.6.1\" and python_version < \"4.0.0\""
 name = "identify"
 optional = false
 python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,>=2.7"
-version = "1.5.4"
+version = "1.5.5"
 
 [package.extras]
 license = ["editdistance"]
@@ -787,6 +787,7 @@ wcwidth = "*"
 [[package]]
 category = "main"
 description = "Run a subprocess in a pseudo terminal"
+marker = "python_version >= \"3.7\" and python_version < \"4.0\" and sys_platform != \"win32\""
 name = "ptyprocess"
 optional = false
 python-versions = "*"
@@ -1171,7 +1172,7 @@ version = "1.12.1"
 [[package]]
 category = "main"
 description = "Backport of pathlib-compatible object wrapper for zip files"
-marker = "python_version >= \"3.5\" and python_version < \"3.8\" or python_version < \"3.8\" or python_version >= \"3.6.1\" and python_version < \"3.8\" or python_version >= \"3.5\" and python_version < \"3.8\" and (python_version >= \"3.5\" and python_version < \"3.8\" or python_version < \"3.8\" or python_version >= \"3.6.1\" and python_version < \"3.8\") or python_version >= \"3.6.1\" and python_version < \"3.7\" or python_version >= \"3.6.1\" and python_version < \"3.7\" and (python_version >= \"3.6.1\" and python_version < \"3.7\" or python_version < \"3.7\") or python_version >= \"3.6.1\" and python_version < \"3.8\" and (python_version >= \"3.5\" and python_version < \"3.8\" or python_version < \"3.8\" or python_version >= \"3.6.1\" and python_version < \"3.8\")"
+marker = "python_version >= \"3.5\" and python_version < \"3.8\" or python_version < \"3.8\" or python_version >= \"3.6.1\" and python_version < \"3.7\" or python_version >= \"3.6.1\" and python_version < \"3.8\""
 name = "zipp"
 optional = false
 python-versions = ">=3.6"
@@ -1182,7 +1183,7 @@ docs = ["sphinx", "jaraco.packaging (>=3.2)", "rst.linker (>=1.9)"]
 testing = ["pytest (>=3.5,<3.7.3 || >3.7.3)", "pytest-checkdocs (>=1.2.3)", "pytest-flake8", "pytest-cov", "jaraco.test (>=3.2.0)", "jaraco.itertools", "func-timeout", "pytest-black (>=0.3.7)", "pytest-mypy"]
 
 [metadata]
-content-hash = "e4a4d7c9fd7fa351a513ea4ab590e227f7c6be042a4a8a3156509f7f5df7a523"
+content-hash = "8df0839a479a0483c969368ef8f61f553773f27bdc0a569603c7141b6c360680"
 python-versions = "^3.6"
 
 [metadata.files]
@@ -1392,8 +1393,8 @@ html5lib = [
     {file = "html5lib-1.1.tar.gz", hash = "sha256:b2e5b40261e20f354d198eae92afc10d750afb487ed5e50f9c4eaf07c184146f"},
 ]
 identify = [
-    {file = "identify-1.5.4-py2.py3-none-any.whl", hash = "sha256:d7da7de6825568daa4449858ce328ecc0e1ada2554d972a6f4f90e736aaf499a"},
+    {file = "identify-1.5.5-py2.py3-none-any.whl", hash = "sha256:da683bfb7669fa749fc7731f378229e2dbf29a1d1337cbde04106f02236eb29d"},
-    {file = "identify-1.5.4.tar.gz", hash = "sha256:e4db4796b3b0cf4f9cb921da51430abffff2d4ba7d7c521184ed5252bd90d461"},
+    {file = "identify-1.5.5.tar.gz", hash = "sha256:7c22c384a2c9b32c5cc891d13f923f6b2653aa83e2d75d8f79be240d6c86c4f4"},
 ]
 idna = [
     {file = "idna-2.10-py2.py3-none-any.whl", hash = "sha256:b97d804b1e9b523befed77c48dacec60e6dcb0b5391d57af6a65a312a90648c0"},

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "tox-poetry-installer"
-version = "0.1.2"
+version = "0.2.1"
 license = "MIT"
 authors = ["Ethan Paul <24588726+enpaul@users.noreply.github.com>"]
 description = "Tox plugin to install Tox environment dependencies using the Poetry backend and lockfile"
@@ -27,7 +27,7 @@ poetry_installer = "tox_poetry_installer"
 
 [tool.poetry.dependencies]
 python = "^3.6"
-poetry = "^1.0.0"
+poetry = ">=1.0.0, <1.1.0"
 tox = "^2.3.0 || ^3.0.0"
 
 [tool.poetry.dev-dependencies]

tox.ini

@@ -4,6 +4,7 @@ isolated_build = true
 
 [testenv]
 description = Run the tests
+require_locked_deps = true
 deps =
     pytest
     pytest-cov
@@ -13,6 +14,7 @@ commands =
 
 [testenv:static]
 description = Static formatting and quality enforcement
+require_locked_deps = true
 basepython = python3.8
 ignore_errors = true
 deps =
@@ -30,6 +32,7 @@ commands =
 
 [testenv:static-tests]
 description = Static formatting and quality enforcement for the tests
+require_locked_deps = true
 basepython = python3.8
 ingore_errors = true
 deps =
@@ -47,6 +50,7 @@ commands =
 
 [testenv:security]
 description = Security checks
+require_locked_deps = true
 basepython = python3.8
 ignore_errors = true
 skip_install = true
@@ -57,6 +61,6 @@ deps =
 allowlist_externals =
     bash
 commands =
-    bandit --recursive {toxinidir}/tox_poetry_installer.py
+    bandit --quiet {toxinidir}/tox_poetry_installer.py
-    bash -c "bandit --skip B101 {toxinidir}/tests/*.py"
+    bash -c "bandit --quiet --skip B101 {toxinidir}/tests/*.py"
     bash -c "poetry export --format requirements.txt --without-hashes --dev | safety check --stdin --bare"

tox_poetry_installer.py

@@ -5,11 +5,12 @@ installation functionality to install dependencies from the Poetry lockfile for
 does this by using ``poetry`` to read in the lockfile, identify necessary dependencies, and then
 use Poetry's ``PipInstaller`` class to install those packages into the Tox environment.
 """
-import logging
 from pathlib import Path
 from typing import Dict
 from typing import List
-from typing import Optional
+from typing import NamedTuple
+from typing import Sequence
+from typing import Set
 from typing import Tuple
 
 from poetry.factory import Factory as PoetryFactory
@@ -20,37 +21,126 @@ from poetry.packages import Package as PoetryPackage
 from poetry.puzzle.provider import Provider as PoetryProvider
 from poetry.utils.env import VirtualEnv as PoetryVirtualEnv
 from tox import hookimpl
+from tox import reporter
 from tox.action import Action as ToxAction
+from tox.config import DepConfig as ToxDepConfig
+from tox.config import Parser as ToxParser
 from tox.venv import VirtualEnv as ToxVirtualEnv
 
 
 __title__ = "tox-poetry-installer"
 __summary__ = "Tox plugin to install Tox environment dependencies using the Poetry backend and lockfile"
-__version__ = "0.1.2"
+__version__ = "0.2.1"
 __url__ = "https://github.com/enpaul/tox-poetry-installer/"
 __license__ = "MIT"
 __authors__ = ["Ethan Paul <24588726+enpaul@users.noreply.github.com>"]
 
 
+# Valid PEP508 version delimiters. These are used to test whether a given string (specifically a
+# dependency name) is just a package name or also includes a version identifier.
 _PEP508_VERSION_DELIMITERS: Tuple[str, ...] = ("~=", "==", "!=", ">", "<")
 
+# Prefix all reporter messages should include to indicate that they came from this module in the
+# console output.
+_REPORTER_PREFIX = f"[{__title__}]:"
+
+# Suffix that indicates an env dependency should be treated as a locked dependency and thus be
+# installed from the lockfile. Will be automatically stripped off of a dependency name during
+# sorting so that the resulting string is just the valid package name. This becomes optional when
+# the "require_locked_deps" option is true for an environment; in that case a bare dependency like
+# 'foo' is treated the same as an explicitly locked dependency like 'foo@poetry'
+_MAGIC_SUFFIX_MARKER = "@poetry"
+
+
+class _SortedEnvDeps(NamedTuple):
+    unlocked_deps: List[ToxDepConfig]
+    locked_deps: List[ToxDepConfig]
+
 
 class ToxPoetryInstallerException(Exception):
     """Error while installing locked dependencies to the test environment"""
 
 
-class NoLockedDependencyError(ToxPoetryInstallerException):
+class LockedDepVersionConflictError(ToxPoetryInstallerException):
-    """Cannot install a package that is not in the lockfile"""
+    """Locked dependencies cannot specify an alternate version for installation"""
 
 
-def _make_poetry(venv: ToxVirtualEnv) -> Poetry:
+class LockedDepNotFoundError(ToxPoetryInstallerException):
-    """Helper to make a poetry object from a toxenv"""
+    """Locked dependency was not found in the lockfile"""
-    return PoetryFactory().create_poetry(venv.envconfig.config.toxinidir)
 
 
-def _find_locked_dependencies(
+def _sort_env_deps(venv: ToxVirtualEnv) -> _SortedEnvDeps:
-    poetry: Poetry, dependency_name: str
+    """Sorts the environment dependencies by lock status
-) -> List[PoetryPackage]:
+
+    Lock status determines whether a given environment dependency will be installed from the
+    lockfile using the Poetry backend, or whether this plugin will skip it and allow it to be
+    installed using the default pip-based backend (an unlocked dependency).
+
+    .. note:: A locked dependency must follow a required format. To avoid reinventing the wheel
+              (no pun intended) this module does not have any infrastructure for parsing PEP-508
+              version specifiers, and so requires locked dependencies to be specified with no
+              version (the installed version being taken from the lockfile). If a dependency is
+              specified as locked and its name is also a PEP-508 string then an error will be
+              raised.
+    """
+
+    reporter.verbosity1(
+        f"{_REPORTER_PREFIX} sorting {len(venv.envconfig.deps)} env dependencies by lock requirement"
+    )
+    unlocked_deps = []
+    locked_deps = []
+
+    for dep in venv.envconfig.deps:
+        if venv.envconfig.require_locked_deps:
+            reporter.verbosity1(
+                f"{_REPORTER_PREFIX} lock required for env, treating '{dep.name}' as locked env dependency"
+            )
+            dep.name = dep.name.replace(_MAGIC_SUFFIX_MARKER, "")
+            locked_deps.append(dep)
+        else:
+            if dep.name.endswith(_MAGIC_SUFFIX_MARKER):
+                reporter.verbosity1(
+                    f"{_REPORTER_PREFIX} specification includes marker '{_MAGIC_SUFFIX_MARKER}', treating '{dep.name}' as locked env dependency"
+                )
+                dep.name = dep.name.replace(_MAGIC_SUFFIX_MARKER, "")
+                locked_deps.append(dep)
+            else:
+                reporter.verbosity1(
+                    f"{_REPORTER_PREFIX} specification does not include marker '{_MAGIC_SUFFIX_MARKER}', treating '{dep.name}' as unlocked env dependency"
+                )
+                unlocked_deps.append(dep)
+
+    reporter.verbosity1(
+        f"{_REPORTER_PREFIX} identified {len(locked_deps)} locked env dependencies for installation from poetry lockfile: {[item.name for item in locked_deps]}"
+    )
+    reporter.verbosity1(
+        f"{_REPORTER_PREFIX} identified {len(unlocked_deps)} unlocked env dependencies for installation using default backend: {[item.name for item in unlocked_deps]}"
+    )
+
+    return _SortedEnvDeps(locked_deps=locked_deps, unlocked_deps=unlocked_deps)
+
+
+def _install_to_venv(
+    poetry: Poetry, venv: ToxVirtualEnv, packages: Sequence[PoetryPackage]
+):
+    """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
+    """
+    installer = PoetryPipInstaller(
+        env=PoetryVirtualEnv(path=Path(venv.envconfig.envdir)),
+        io=PoetryNullIO(),
+        pool=poetry.pool,
+    )
+
+    for dependency in packages:
+        reporter.verbosity1(f"{_REPORTER_PREFIX} installing {dependency}")
+        installer.install(dependency)
+
+
+def _find_transients(poetry: Poetry, dependency_name: str) -> Set[PoetryPackage]:
     """Using a poetry object identify all dependencies of a specific dependency
 
     :param poetry: Populated poetry object which can be used to build a populated locked
@@ -70,35 +160,93 @@ def _find_locked_dependencies(
     try:
         top_level = packages[dependency_name]
 
-        def find_transients(name: str) -> List[PoetryPackage]:
+        def find_deps_of_deps(name: str) -> List[PoetryPackage]:
             if name in PoetryProvider.UNSAFE_PACKAGES:
+                reporter.warning(
+                    f"{_REPORTER_PREFIX} installing '{name}' using Poetry is not supported; skipping"
+                )
                 return []
             transients = [packages[name]]
             for dep in packages[name].requires:
-                transients += find_transients(dep.name)
+                transients += find_deps_of_deps(dep.name)
             return transients
 
-        return find_transients(top_level.name)
+        return set(find_deps_of_deps(top_level.name))
 
     except KeyError:
         if any(
             delimiter in dependency_name for delimiter in _PEP508_VERSION_DELIMITERS
         ):
-            message = "specifying a version in the tox environment definition is incompatible with installing from a lockfile"
+            raise LockedDepVersionConflictError(
-        else:
+                f"Locked dependency '{dependency_name}' cannot include version specifier"
-            message = (
+            ) from None
-                "no version of the package was found in the current project's lockfile"
+        raise LockedDepNotFoundError(
-            )
+            f"No version of locked dependency '{dependency_name}' found in the project lockfile"
-
-        raise NoLockedDependencyError(
-            f"Cannot install requirement '{dependency_name}': {message}"
         ) from None
 
 
+def _install_env_dependencies(venv: ToxVirtualEnv, poetry: Poetry):
+    env_deps = _sort_env_deps(venv)
+
+    dependencies: List[PoetryPackage] = []
+    for dep in env_deps.locked_deps:
+        try:
+            dependencies += _find_transients(poetry, dep.name)
+        except ToxPoetryInstallerException as err:
+            venv.status = "lockfile installation failed"
+            reporter.error(f"{_REPORTER_PREFIX} {err}")
+            raise err
+
+    reporter.verbosity1(
+        f"{_REPORTER_PREFIX} identified {len(dependencies)} actual dependencies from {len(venv.envconfig.deps)} specified env dependencies"
+    )
+
+    reporter.verbosity1(
+        f"{_REPORTER_PREFIX} updating env config with {len(env_deps.unlocked_deps)} unlocked env dependencies for installation using the default backend"
+    )
+    venv.envconfig.deps = env_deps.unlocked_deps
+
+    reporter.verbosity0(
+        f"{_REPORTER_PREFIX} ({venv.name}) installing {len(dependencies)} env dependencies from lockfile"
+    )
+    _install_to_venv(poetry, venv, dependencies)
+
+
+def _install_package_dependencies(venv: ToxVirtualEnv, poetry: Poetry):
+    reporter.verbosity1(
+        f"{_REPORTER_PREFIX} performing installation of project dependencies"
+    )
+
+    primary_dependencies = poetry.locker.locked_repository(False).packages
+
+    reporter.verbosity1(
+        f"{_REPORTER_PREFIX} identified {len(primary_dependencies)} dependencies of project '{poetry.package.name}'"
+    )
+
+    reporter.verbosity0(
+        f"{_REPORTER_PREFIX} ({venv.name}) installing {len(primary_dependencies)} project dependencies from lockfile"
+    )
+    _install_to_venv(poetry, venv, primary_dependencies)
+
+
 @hookimpl
-def tox_testenv_install_deps(
+def tox_addoption(parser: ToxParser):
-    venv: ToxVirtualEnv, action: ToxAction
+    """Add required configuration options to the tox INI file
-) -> Optional[List[PoetryPackage]]:
+
+    Adds the ``require_locked_deps`` configuration option to the venv to check whether all
+    dependencies should be treated as locked or not.
+    """
+
+    parser.add_testenv_attribute(
+        name="require_locked_deps",
+        type="bool",
+        default=False,
+        help="Require all dependencies in the environment be installed using the Poetry lockfile",
+    )
+
+
+@hookimpl
+def tox_testenv_install_deps(venv: ToxVirtualEnv, action: ToxAction):
     """Install the dependencies for the current environment
 
     Loads the local Poetry environment and the corresponding lockfile then pulls the dependencies
@@ -109,34 +257,34 @@ def tox_testenv_install_deps(
     :param action: Tox action object
     """
 
-    logger = logging.getLogger(__name__)
-
     if action.name == venv.envconfig.config.isolated_build_env:
-        logger.debug(
+        # Skip running the plugin for the packaging environment. PEP-517 front ends can handle
-            f"Environment {action.name} is isolated build environment; skipping Poetry-based dependency installation"
+        # that better than we can, so let them do their thing. More to the point: if you're having
+        # problems in the packaging env that this plugin would solve, god help you.
+        reporter.verbosity1(
+            f"{_REPORTER_PREFIX} skipping isolated build env '{action.name}'"
         )
-        return None
+        return
 
-    poetry = _make_poetry(venv)
+    poetry = PoetryFactory().create_poetry(venv.envconfig.config.toxinidir)
 
-    logger.debug(f"Loaded project pyproject.toml from {poetry.file}")
+    reporter.verbosity1(
-
+        f"{_REPORTER_PREFIX} loaded project pyproject.toml from {poetry.file}"
-    dependencies: List[PoetryPackage] = []
-    for env_dependency in venv.envconfig.deps:
-        dependencies += _find_locked_dependencies(poetry, env_dependency.name)
-
-    logger.debug(
-        f"Identified {len(dependencies)} dependencies for environment {action.name}"
     )
 
-    installer = PoetryPipInstaller(
+    # Handle the installation of any locked env dependencies from the lockfile
-        env=PoetryVirtualEnv(path=Path(venv.envconfig.envdir)),
+    _install_env_dependencies(venv, poetry)
-        io=PoetryNullIO(),
-        pool=poetry.pool,
-    )
 
-    for dependency in dependencies:
+    # Handle the installation of the package dependencies from the lockfile if the package is
-        logger.info(f"Installing environment dependency: {dependency}")
+    # being installed to this venv; otherwise skip installing the package dependencies
-        installer.install(dependency)
+    if not venv.envconfig.skip_install and not venv.envconfig.config.skipsdist:
-
+        _install_package_dependencies(venv, poetry)
-    return dependencies
+    else:
+        if venv.envconfig.skip_install:
+            reporter.verbosity1(
+                f"{_REPORTER_PREFIX} env specifies 'skip_install = true', skipping installation of project package"
+            )
+        elif venv.envconfig.config.skipsdist:
+            reporter.verbosity1(
+                f"{_REPORTER_PREFIX} config specifies 'skipsdist = true', skipping installation of project package"
+            )