From 604b8053279b01e6781ba7d27740a115c95ee9d8 Mon Sep 17 00:00:00 2001
From: Yilei Yang <yileiyang@google.com>
Date: Tue, 4 Oct 2022 20:39:24 -0700
Subject: [PATCH] Fix an issue where empty lines were added between comments
 inside decorators.

---
 src/black/lines.py              | 2 ++
 tests/data/preview/comments9.py | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/src/black/lines.py b/src/black/lines.py
index 9f0471f9413..f7c8b5fec13 100644
--- a/src/black/lines.py
+++ b/src/black/lines.py
@@ -513,6 +513,8 @@ def maybe_empty_lines(self, current_line: Line) -> LinesBlock:
         if current_line.is_comment:
             if self.previous_line is None or (
                 not self.previous_line.is_decorator
+                # `or before` means this comment already has an empty line before
+                and (not self.previous_line.is_comment or before)
                 and (self.semantic_leading_comment is None or before)
             ):
                 self.semantic_leading_comment = block
diff --git a/tests/data/preview/comments9.py b/tests/data/preview/comments9.py
index 1919a97fe45..359d1412158 100644
--- a/tests/data/preview/comments9.py
+++ b/tests/data/preview/comments9.py
@@ -37,6 +37,7 @@ class MyClassAfterAnotherClassWithDocstring:
 # leading 1
 @deco1
 # leading 2
+# leading 2 extra
 @deco2(with_args=True)
 # leading 3
 @deco3
@@ -158,6 +159,7 @@ class MyClassAfterAnotherClassWithDocstring:
 # leading 1
 @deco1
 # leading 2
+# leading 2 extra
 @deco2(with_args=True)
 # leading 3
 @deco3