⚡️ Speed up function deselect_by_mark by 5%

src/_pytest/mark/__init__.py

@@ -239,11 +239,14 @@ def deselect_by_mark(items: "List[Item]", config: Config) -> None:
     expr = _parse_expression(matchexpr, "Wrong expression passed to '-m'")
     remaining: List[Item] = []
     deselected: List[Item] = []
+    remaining_append = remaining.append
+    deselected_append = deselected.append
+
     for item in items:
         if expr.evaluate(MarkMatcher.from_item(item)):
-            remaining.append(item)
+            remaining_append(item)
         else:
-            deselected.append(item)
+            deselected_append(item)
     if deselected:
         config.hook.pytest_deselected(items=deselected)
         items[:] = remaining

src/_pytest/mark/expression.py

@@ -28,6 +28,9 @@
 from typing import Sequence
 
 
+_EMPTY_BUILTINS = {"__builtins__": {}}
+
+
 __all__ = [
     "Expression",
     "ParseError",
@@ -46,7 +49,7 @@ class TokenType(enum.Enum):
 
 @dataclasses.dataclass(frozen=True)
 class Token:
-    __slots__ = ("type", "value", "pos")
+    __slots__ = ("pos", "type", "value")
     type: TokenType
     value: str
     pos: int
@@ -68,7 +71,7 @@ def __str__(self) -> str:
 
 
 class Scanner:
-    __slots__ = ("tokens", "current")
+    __slots__ = ("current", "tokens")
 
     def __init__(self, input: str) -> None:
         self.tokens = self.lex(input)
@@ -219,5 +222,5 @@ def evaluate(self, matcher: Callable[[str], bool]) -> bool:
 
         :returns: Whether the expression matches or not.
         """
-        ret: bool = eval(self.code, {"__builtins__": {}}, MatcherAdapter(matcher))
+        ret: bool = eval(self.code, _EMPTY_BUILTINS, MatcherAdapter(matcher))
         return ret