Project plugins and forcing a minimum poetry version

docs/plugins.md

@@ -255,6 +255,28 @@ You can also list all currently installed plugins by running:
 poetry self show plugins
 ```
 
+### Project plugins
+
+You can also specify that a plugin is required for your project
+in the `tool.poetry.requires-plugins` section of the pyproject.toml file:
+
+```toml
+[tool.poetry.requires-plugins]
+my-application-plugin = ">1.0"
+```
+
+If the plugin is not installed in Poetry's own environment when running `poetry install`,
+it will be installed only for the current project under `.poetry/plugins`
+in the project's directory.
+
+The syntax to specify `plugins` is the same as for [dependencies]({{< relref "managing-dependencies" >}}).
+
+{{% warning %}}
+You can even overwrite a plugin in Poetry's own environment with another version.
+However, if a plugin's dependencies are not compatible with packages in Poetry's own
+environment, installation will fail.
+{{% /warning %}}
+
 
 ## Maintaining a plugin
 

docs/pyproject.md

@@ -843,6 +843,29 @@ any custom url in the `urls` section.
 
 If you publish your package on PyPI, they will appear in the `Project Links` section.
 
+## `requires-poetry`
+
+A constraint for the Poetry version that is required for this project.
+If you are using a Poetry version that is not allowed by this constraint,
+an error will be raised.
+
+```toml
+[tool.poetry]
+requires-poetry = ">=2.0"
+```
+
+## `requires-plugins`
+
+In this section, you can specify that certain plugins are required for your project:
+
+```toml
+[tool.poetry.requires-plugins]
+my-application-plugin = ">=1.0"
+my-plugin = ">=1.0,<2.0"
+```
+
+See [Project plugins]({{< relref "plugins#project-plugins" >}}) for more information.
+
 ## Poetry and PEP-517
 
 [PEP-517](https://www.python.org/dev/peps/pep-0517/) introduces a standard way

src/poetry/console/application.py

@@ -4,7 +4,9 @@
 import re
 
 from contextlib import suppress
+from functools import cached_property
 from importlib import import_module
+from pathlib import Path
 from typing import TYPE_CHECKING
 from typing import cast
 
@@ -111,20 +113,13 @@ def __init__(self) -> None:
 
     @property
     def poetry(self) -> Poetry:
-        from pathlib import Path
-
         from poetry.factory import Factory
 
         if self._poetry is not None:
             return self._poetry
 
-        project_path = Path.cwd()
-
-        if self._io and self._io.input.option("directory"):
-            project_path = Path(self._io.input.option("directory")).absolute()
-
         self._poetry = Factory().create_poetry(
-            cwd=project_path,
+            cwd=self._directory,
             io=self._io,
             disable_plugins=self._disable_plugins,
             disable_cache=self._disable_cache,
@@ -340,6 +335,7 @@ def _load_plugins(self, io: IO | None = None) -> None:
             from poetry.plugins.application_plugin import ApplicationPlugin
             from poetry.plugins.plugin_manager import PluginManager
 
+            PluginManager.add_project_plugin_path(self._directory)
             manager = PluginManager(ApplicationPlugin.group)
             manager.load_plugins()
             manager.activate(self)
@@ -382,6 +378,12 @@ def _default_definition(self) -> Definition:
 
         return definition
 
+    @cached_property
+    def _directory(self) -> Path:
+        if self._io and self._io.input.option("directory"):
+            return Path(self._io.input.option("directory")).absolute()
+        return Path.cwd()
+
 
 def main() -> int:
     exit_code: int = Application().run()

src/poetry/console/commands/install.py

@@ -6,6 +6,7 @@
 from cleo.helpers import option
 
 from poetry.console.commands.installer_command import InstallerCommand
+from poetry.plugins.plugin_manager import PluginManager
 
 
 if TYPE_CHECKING:
@@ -104,6 +105,8 @@ def handle(self) -> int:
 
         from poetry.masonry.builders.editable import EditableBuilder
 
+        PluginManager.ensure_project_plugins(self.poetry, self.io)
+
         if self.option("extras") and self.option("all-extras"):
             self.line_error(
                 "<error>You cannot specify explicit"

src/poetry/console/commands/self/show/plugins.py

@@ -70,9 +70,7 @@ def _system_project_handle(self) -> int:
         }
 
         for group in [ApplicationPlugin.group, Plugin.group]:
-            for entry_point in PluginManager(group).get_plugin_entry_points(
-                env=system_env
-            ):
+            for entry_point in PluginManager(group).get_plugin_entry_points():
                 assert entry_point.dist is not None
 
                 package = packages_by_name[canonicalize_name(entry_point.dist.name)]

src/poetry/factory.py

@@ -10,9 +10,12 @@
 
 from cleo.io.null_io import NullIO
 from packaging.utils import canonicalize_name
+from poetry.core.constraints.version import Version
+from poetry.core.constraints.version import parse_constraint
 from poetry.core.factory import Factory as BaseFactory
 from poetry.core.packages.dependency_group import MAIN_GROUP
 
+from poetry.__version__ import __version__
 from poetry.config.config import Config
 from poetry.exceptions import PoetryError
 from poetry.json import validate_object
@@ -56,6 +59,15 @@ def create_poetry(
 
         base_poetry = super().create_poetry(cwd=cwd, with_groups=with_groups)
 
+        if version_str := base_poetry.local_config.get("requires-poetry"):
+            version_constraint = parse_constraint(version_str)
+            version = Version.parse(__version__)
+            if not version_constraint.allows(version):
+                raise PoetryError(
+                    f"This project requires Poetry {version_constraint},"
+                    f" but you are using Poetry {version}"
+                )
+
         poetry_file = base_poetry.pyproject_path
         locker = Locker(poetry_file.parent / "poetry.lock", base_poetry.pyproject.data)
 
@@ -99,9 +111,10 @@ def create_poetry(
             )
         )
 
-        plugin_manager = PluginManager(Plugin.group, disable_plugins=disable_plugins)
-        plugin_manager.load_plugins()
-        plugin_manager.activate(poetry, io)
+        if not disable_plugins:
+            plugin_manager = PluginManager(Plugin.group)
+            plugin_manager.load_plugins()
+            plugin_manager.activate(poetry, io)
 
         return poetry