Fix E301 not triggering on decorated methods.

crates/ruff_linter/resources/test/fixtures/pycodestyle/E30.py

@@ -466,6 +466,29 @@ def fn2():
 # end
 
 
+# E301
+class Class:
+    """Class for minimal repo."""
+
+    columns = []
+    @classmethod
+    def cls_method(cls) -> None:
+        pass
+# end
+
+
+# E301
+class Class:
+    """Class for minimal repo."""
+
+    def method(cls) -> None:
+        pass
+    @classmethod
+    def cls_method(cls) -> None:
+        pass
+# end
+
+
 # E302
 """Main module."""
 def fn():

crates/ruff_linter/src/rules/pycodestyle/rules/blank_lines.rs

@@ -658,7 +658,9 @@ impl BlankLinesChecker {
         if self.is_not_first_logical_line {
             if line.preceding_blank_lines == 0
                 // Only applies to methods.
-                && matches!(line.kind,  LogicalLineKind::Function)
+                && matches!(line.kind,  LogicalLineKind::Function | LogicalLineKind::Decorator)
+                // Allow groups of one-liners.
+                && !(matches!(self.follows, Follows::Def) && !matches!(line.last_token, TokenKind::Colon))
                 && matches!(self.class_status, Status::Inside(_))
                 // The class/parent method's docstring can directly precede the def.
                 // Allow following a decorator (if there is an error it will be triggered on the first decorator).

crates/ruff_linter/src/rules/pycodestyle/snapshots/ruff_linter__rules__pycodestyle__tests__E301_E30.py.snap

@@ -41,4 +41,43 @@ E30.py:464:5: E301 [*] Expected 1 blank line, found 0
 464 465 |     def fn2():
 465 466 |         pass
 
+E30.py:474:5: E301 [*] Expected 1 blank line, found 0
+    |
+473 |     columns = []
+474 |     @classmethod
+    |     ^ E301
+475 |     def cls_method(cls) -> None:
+476 |         pass
+    |
+    = help: Add missing blank line
+
+ℹ Safe fix
+471 471 |     """Class for minimal repo."""
+472 472 | 
+473 473 |     columns = []
+    474 |+
+474 475 |     @classmethod
+475 476 |     def cls_method(cls) -> None:
+476 477 |         pass
+
+E30.py:486:5: E301 [*] Expected 1 blank line, found 0
+    |
+484 |     def method(cls) -> None:
+485 |         pass
+486 |     @classmethod
+    |     ^ E301
+487 |     def cls_method(cls) -> None:
+488 |         pass
+    |
+    = help: Add missing blank line
+
+ℹ Safe fix
+483 483 | 
+484 484 |     def method(cls) -> None:
+485 485 |         pass
+    486 |+
+486 487 |     @classmethod
+487 488 |     def cls_method(cls) -> None:
+488 489 |         pass
+