plugin manager: use system env paths for discovery

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

@@ -40,12 +40,10 @@ def _system_project_handle(self) -> int:
             }
         )
 
-        entry_points = (
-            PluginManager(ApplicationPlugin.group).get_plugin_entry_points()
-            + PluginManager(Plugin.group).get_plugin_entry_points()
-        )
-
         system_env = EnvManager.get_system_env(naive=True)
+        entry_points = PluginManager(ApplicationPlugin.group).get_plugin_entry_points(
+            env=system_env
+        ) + PluginManager(Plugin.group).get_plugin_entry_points(env=system_env)
         installed_repository = InstalledRepository.load(
             system_env, with_dependencies=True
         )

src/poetry/plugins/plugin_manager.py

@@ -1,15 +1,22 @@
 from __future__ import annotations
 
 import logging
+import sys
 
-from typing import Any
+from typing import TYPE_CHECKING
 
 import entrypoints
 
 from poetry.plugins.application_plugin import ApplicationPlugin
 from poetry.plugins.plugin import Plugin
 
 
+if TYPE_CHECKING:
+    from typing import Any
+
+    from poetry.utils.env import Env
+
+
 logger = logging.getLogger(__name__)
 
 
@@ -23,17 +30,21 @@ def __init__(self, group: str, disable_plugins: bool = False) -> None:
         self._disable_plugins = disable_plugins
         self._plugins: list[Plugin] = []
 
-    def load_plugins(self) -> None:
+    def load_plugins(self, env: Env | None = None) -> None:
         if self._disable_plugins:
             return
 
-        plugin_entrypoints = self.get_plugin_entry_points()
+        plugin_entrypoints = self.get_plugin_entry_points(env=env)
 
         for entrypoint in plugin_entrypoints:
             self._load_plugin_entrypoint(entrypoint)
 
-    def get_plugin_entry_points(self) -> list[entrypoints.EntryPoint]:
-        return entrypoints.get_group_all(self._group)
+    def get_plugin_entry_points(
+        self, env: Env | None = None
+    ) -> list[entrypoints.EntryPoint]:
+        return entrypoints.get_group_all(
+            self._group, path=env.sys_path if env else sys.path
+        )
 
     def add_plugin(self, plugin: Plugin) -> None:
         if not isinstance(plugin, (Plugin, ApplicationPlugin)):