Remove empty lines before docstrings in async functions (#4132)

CHANGES.md

@@ -17,6 +17,7 @@
 - Format module docstrings the same as class and function docstrings (#4095)
 - Fix bug where spaces were not added around parenthesized walruses in subscripts,
   unlike other binary operators (#4109)
+- Remove empty lines before docstrings in async functions (#4132)
 - Address a missing case in the change to allow empty lines at the beginning of all
   blocks, except immediately before a docstring (#4130)
 

src/black/lines.py

@@ -24,7 +24,6 @@
     TEST_DESCENDANTS,
     child_towards,
     is_docstring,
-    is_funcdef,
     is_import,
     is_multiline_string,
     is_one_sequence_between,
@@ -708,13 +707,8 @@ def _maybe_empty_lines(self, current_line: Line) -> Tuple[int, int]:
         is_empty_first_line_ok = (
             Preview.allow_empty_first_line_in_block in current_line.mode
             and (
-                not is_docstring(current_line.leaves[0], current_line.mode)
+                not current_line.is_docstring
-                or (
+                or (self.previous_line and not self.previous_line.is_def)
-                    self.previous_line
-                    and self.previous_line.leaves[0]
-                    and self.previous_line.leaves[0].parent
-                    and not is_funcdef(self.previous_line.leaves[0].parent)
-                )
             )
         )
 

src/black/nodes.py

@@ -742,10 +742,6 @@ def is_multiline_string(leaf: Leaf) -> bool:
     return has_triple_quotes(leaf.value) and "\n" in leaf.value
 
 
-def is_funcdef(node: Node) -> bool:
-    return node.type == syms.funcdef
-
-
 def is_function_or_class(node: Node) -> bool:
     return node.type in {syms.funcdef, syms.classdef, syms.async_funcdef}
 

tests/data/cases/preview_allow_empty_first_line.py

@@ -63,6 +63,17 @@ def method(self):
         pass
 
 
+async def async_fn():
+
+    """Docstring."""
+
+
+@decorated
+async def async_fn():
+
+    """Docstring."""
+
+    
 def top_level(
     a: int,
     b: str,
@@ -138,6 +149,15 @@ def method(self):
         pass
 
 
+async def async_fn():
+    """Docstring."""
+
+
+@decorated
+async def async_fn():
+    """Docstring."""
+
+
 def top_level(
     a: int,
     b: str,