Correct bug in parser

The prefix of class declarations should never belong to the `kind`, but the `J.ClassDeclaration`.

Author: knutwannheden

rewrite/rewrite/python/_parser_visitor.py

@@ -222,7 +222,7 @@ def visit_AsyncFunctionDef(self, node):
         return self.visit_FunctionDef(node)
 
     def visit_ClassDef(self, node):
-        prefix = self.__whitespace() if node.decorator_list else Space.EMPTY
+        prefix = self.__whitespace()
         decorators = [self.__map_decorator(d) for d in node.decorator_list]
         kind_prefix = self.__source_before('class')
         name = self.__convert_name(node.name)

rewrite/rewrite/python/format/normalize_format.py

@@ -22,6 +22,8 @@ def visit_class_declaration(self, cd: ClassDeclaration, p: P) -> J:
             cd = cd.with_leading_annotations(Space.format_first_prefix(cd.leading_annotations, Space.EMPTY))
             return cd
 
+        cd = _concatenate_prefix(cd, cd.padding.kind.prefix)
+        cd = cd.padding.with_kind(cd.padding.kind.with_prefix(Space.EMPTY))
         return cd
 
     def visit_method_declaration(self, md: MethodDeclaration, p: P) -> J:

rewrite/tests/python/all/format/blank_lines_test.py

@@ -1,5 +1,5 @@
 from rewrite.java import Space
-from rewrite.python import IntelliJ
+from rewrite.python import IntelliJ, NormalizeFormatVisitor
 from rewrite.python.format import BlankLinesVisitor
 from rewrite.test import rewrite_run, python, RecipeSpec, from_visitor
 
@@ -19,3 +19,35 @@ def test_remove_leading_module_blank_lines():
         spec=RecipeSpec()
         .with_recipe(from_visitor(BlankLinesVisitor(IntelliJ.blank_lines())))
     )
+
+
+def test_blank_lines_between_top_level_declarations():
+    rewrite_run(
+        # language=python
+        python(
+            """\
+            class Foo:
+                pass
+            class Bar:
+                pass
+            def f():
+                pass
+            """,
+            """\
+            class Foo:
+                pass
+
+
+            class Bar:
+                pass
+
+
+            def f():
+                pass
+            """
+        ),
+        spec=RecipeSpec()
+        .with_recipes(
+            from_visitor(BlankLinesVisitor(IntelliJ.blank_lines()))
+        )
+    )