Improve performance by caching entry points

src/docc/__init__.py

@@ -1,4 +1,4 @@
-# Copyright (C) 2022-2025 Ethereum Foundation
+# Copyright (C) 2022-2026 Ethereum Foundation
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -17,5 +17,5 @@
 The documentation compiler.
 """
 
-__version__ = "0.4.0"
+__version__ = "0.4.1"
 "Current version of docc"

src/docc/plugins/html/__init__.py

@@ -1,4 +1,4 @@
-# Copyright (C) 2022-2023 Ethereum Foundation
+# Copyright (C) 2022-2026 Ethereum Foundation
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -62,7 +62,7 @@
     Visitor,
 )
 from docc.plugins import references
-from docc.plugins.loader import PluginError
+from docc.plugins.loader import PluginError, entry_points_by_group
 from docc.plugins.references import Index, ReferenceError
 from docc.plugins.resources import ResourceSource
 from docc.plugins.search import Search
@@ -71,9 +71,9 @@
 from docc.transform import Transform
 
 if sys.version_info < (3, 10):
-    from importlib_metadata import EntryPoint, entry_points
+    from importlib_metadata import EntryPoint
 else:
-    from importlib.metadata import EntryPoint, entry_points
+    from importlib.metadata import EntryPoint
 
 
 RenderResult = Optional[Union["HTMLTag", "HTMLRoot"]]
@@ -425,8 +425,7 @@ class HTMLVisitor(Visitor):
 
     def __init__(self, context: Context) -> None:
         # Discover render functions.
-        found = entry_points(group="docc.plugins.html")
-        self.entry_points = {entry.name: entry for entry in found}
+        self.entry_points = entry_points_by_group("docc.plugins.html")
         self.root = HTMLRoot(context)
         self.stack = [self.root]
         self.renderers = {}

src/docc/plugins/loader.py

@@ -18,6 +18,7 @@
 """
 
 import sys
+from functools import cache
 from inspect import isabstract
 from typing import Callable, Dict, Type, TypeVar
 
@@ -33,6 +34,18 @@ class PluginError(Exception):
     """
 
 
+@cache
+def entry_points_by_group(group: str) -> Dict[str, EntryPoint]:
+    """
+    Find [entry points][p] belonging to `group`, permanently caching the
+    result.
+
+    [p]: https://packaging.python.org/en/latest/specifications/entry-points/
+    """
+    found = entry_points(group=group)
+    return {entry.name: entry for entry in found}
+
+
 L = TypeVar("L")
 
 
@@ -47,8 +60,7 @@ def __init__(self) -> None:
         """
         Create an instance and populate it with the discovered plugins.
         """
-        found = set(entry_points(group="docc.plugins"))
-        self.entry_points = {entry.name: entry for entry in found}
+        self.entry_points = entry_points_by_group("docc.plugins")
 
     def load(self, base: Type[L], name: str) -> Callable[..., L]:
         """