Add __slots__ to most classes

A bit more efficient, and prevents typo mistakes.

Author: bluetech

src/pluggy/_hooks.py

@@ -58,6 +58,8 @@ class HookspecMarker:
     if the :py:class:`.PluginManager` uses the same project_name.
     """
 
+    __slots__ = ("project_name",)
+
     def __init__(self, project_name: str) -> None:
         self.project_name = project_name
 
@@ -127,6 +129,8 @@ class HookimplMarker:
     if the :py:class:`.PluginManager` uses the same project_name.
     """
 
+    __slots__ = ("project_name",)
+
     def __init__(self, project_name: str) -> None:
         self.project_name = project_name
 
@@ -263,9 +267,9 @@ def varnames(func: object) -> Tuple[Tuple[str, ...], Tuple[str, ...]]:
 
 class _HookRelay:
     """hook holder object for performing 1:N hook calls where N is the number
-    of registered plugins.
+    of registered plugins."""
 
-    """
+    __slots__ = ("__dict__",)
 
     if TYPE_CHECKING:
 
@@ -274,6 +278,15 @@ def __getattr__(self, name: str) -> "_HookCaller":
 
 
 class _HookCaller:
+    __slots__ = (
+        "name",
+        "spec",
+        "_hookexec",
+        "_wrappers",
+        "_nonwrappers",
+        "_call_history",
+    )
+
     def __init__(
         self,
         name: str,
@@ -282,9 +295,9 @@ def __init__(
         spec_opts: Optional["_HookSpecOpts"] = None,
     ) -> None:
         self.name = name
+        self._hookexec = hook_execute
         self._wrappers: List[HookImpl] = []
         self._nonwrappers: List[HookImpl] = []
-        self._hookexec = hook_execute
         self._call_history: Optional[
             List[Tuple[Mapping[str, object], Optional[Callable[[Any], None]]]]
         ] = None
@@ -439,6 +452,19 @@ def _maybe_apply_history(self, method: "HookImpl") -> None:
 
 
 class HookImpl:
+    __slots__ = (
+        "function",
+        "argnames",
+        "kwargnames",
+        "plugin",
+        "opts",
+        "plugin_name",
+        "hookwrapper",
+        "optionalhook",
+        "tryfirst",
+        "trylast",
+    )
+
     def __init__(
         self,
         plugin: _Plugin,
@@ -461,6 +487,16 @@ def __repr__(self) -> str:
 
 
 class HookSpec:
+    __slots__ = (
+        "namespace",
+        "function",
+        "name",
+        "argnames",
+        "kwargnames",
+        "opts",
+        "warn_on_impl",
+    )
+
     def __init__(self, namespace: _Namespace, name: str, opts: "_HookSpecOpts") -> None:
         self.namespace = namespace
         self.function: Callable[..., object] = getattr(namespace, name)

src/pluggy/_manager.py

@@ -99,6 +99,16 @@ class PluginManager:
     which will subsequently send debug information to the trace helper.
     """
 
+    __slots__ = (
+        "project_name",
+        "_name2plugin",
+        "_plugin2hookcallers",
+        "_plugin_distinfo",
+        "trace",
+        "hook",
+        "_inner_hookexec",
+    )
+
     def __init__(self, project_name: str) -> None:
         self.project_name = project_name
         self._name2plugin: Dict[str, _Plugin] = {}

src/pluggy/_result.py

@@ -38,6 +38,8 @@ class HookCallError(Exception):
 
 
 class _Result(Generic[_T]):
+    __slots__ = ("_result", "_excinfo")
+
     def __init__(self, result: Optional[_T], excinfo: Optional[_ExcInfo]) -> None:
         self._result = result
         self._excinfo = excinfo